TY - RPRT N1 - WCRP Informal Report No. 7/2009 ID - soton68701 UR - https://eprints.soton.ac.uk/68701/ Y1 - 2009/09// PB - International CLIVAR Project Office T3 - 139 KW - CLIVAR KW - WCRP KW - climate change KW - atlantic M1 - project_report TI - Report of the Ninth Meeting of the Atlantic Implementation Panel, 18 - 19 September 2008, Woods Hole Oceanographic Institution, U.S.A. AV - public EP - 27 ER - TY - RPRT N1 - WCRP Informal Report No. 1/2008 ID - soton50121 UR - https://eprints.soton.ac.uk/50121/ Y1 - 2008/01// PB - International CLIVAR Project Office T3 - 125 KW - CLIVAR KW - WCRP KW - Workshop Report KW - South Atlantic KW - Meridional Overturning Circulation KW - mass transports M1 - project_report TI - Workshop Report: A monitoring system for heat and mass transports in the South Atlantic as a component of the Meridional Overturning Circulation, Estancia San Ceferino, Buenos Aires, Argentina, May 8, 9, and 10, 2007 AV - public EP - 38 ER - TY - RPRT N1 - WCRP Informal Report No. 13/2007 ID - soton47975 UR - https://eprints.soton.ac.uk/47975/ Y1 - 2007/07// PB - International CLIVAR Project Office T3 - 120 KW - CLIVAR KW - WCRP KW - atlantic KW - climate change M1 - project_report TI - Report of the eighth meeting of the Atlantic Implementation Panel, 21-22 March 2007, Kiel, Germany AV - public EP - 36 ER - TY - RPRT ID - soton46324 UR - https://eprints.soton.ac.uk/46324/ Y1 - 2007/06// PB - International CLIVAR Project Office T3 - 114 KW - CLIVAR KW - WCRP KW - OOPC KW - IAI KW - Workshop KW - South Atlantic KW - Climate observing system KW - SACOS M1 - project_report TI - Report of the CLIVAR/OOPC/IAI Workshop on the South Atlantic Climate Observing System (SACOS), February 6-8, 2003, Hotel Portogalo, Angra dos Reis - Brazil. AV - public EP - 123 ER - TY - RPRT N1 - WCRP Informal Report No. 10/2006 ID - soton28965 UR - https://eprints.soton.ac.uk/28965/ Y1 - 2006/05// PB - International CLIVAR Project Office T3 - 87 KW - CLIVAR KW - WCRP KW - Atlantic KW - North Atlantic KW - Thermohaline Circulation M1 - project_report TI - Report of the CLIVAR Workshop on North Atlantic Thermohaline Circulation Variability AV - public EP - 62 ER - TY - RPRT N1 - WCRP Informal Report No. 1/2006 ID - soton19362 UR - https://eprints.soton.ac.uk/19362/ Y1 - 2006/01// PB - International CLIVAR Project Office T3 - 99 KW - CLIVAR KW - WCRP KW - Atlantic M1 - project_report TI - Report of the 7th Session of the CLIVAR Atlantic Implementation Panel (AIP), 20-21 October 2005 AV - public EP - 22 ER - TY - RPRT N1 - WCRP Informal Report No. 7/2005 ID - soton18763 UR - https://eprints.soton.ac.uk/18763/ Y1 - 2005/05// PB - International CLIVAR Project Office T3 - 91 KW - CLIVAR KW - WCRP KW - Atlantic KW - TACE KW - Tropical M1 - project_report TI - Report of the TACE Implementation Workshop, 3rd February 2005, Miami USA AV - public EP - 22 ER - TY - RPRT N1 - WCRP Informal Report No. 21/2004 ID - soton18766 UR - https://eprints.soton.ac.uk/18766/ Y1 - 2004/12// PB - International CLIVAR Project Office T3 - 86 KW - CLIVAR KW - WCRP KW - Atlantic M1 - project_report TI - Report of the 6th Meeting of the CLIVAR Atlantic Implementation Panel, 20 June 2004 Baltimore, USA AV - public EP - 22 ER - TY - RPRT N1 - WCRP Informal Report No. 11/2004 ID - soton18771 UR - https://eprints.soton.ac.uk/18771/ Y1 - 2004/10// PB - International CLIVAR Project Office T3 - 81 KW - clivar KW - wcrp KW - atlantic KW - climate KW - predictability M1 - project_report TI - Report on the Proceedings of the CLIVAR Workshop on Atlantic Climate Predictability, 19-22 April 2004, Reading, UK AV - public EP - 290 ER - TY - RPRT N1 - WCRP Informal Report No. 16/2003 ID - soton18823 UR - https://eprints.soton.ac.uk/18823/ Y1 - 2003/11// PB - International CLIVAR Project Office T3 - 73 KW - CLIVAR KW - WCRP KW - Atlantic M1 - project_report TI - Report of the 5th meeting of the CLIVAR Atlantic Implementation Panel, 13-14 April 2003, Villefranche-sur-Mer, France AV - public EP - 35 ER - TY - RPRT N1 - WCRP Informal Report No. 20/2002 ID - soton19175 UR - https://eprints.soton.ac.uk/19175/ Y1 - 2002/11// PB - International CLIVAR Project Office T3 - 69 KW - CLIVAR KW - WCRP KW - Atlantic M1 - project_report TI - Report of the 4th meeting of the CLIVAR Atlantic Implementation Panel, 10-12 July 2002, Bermuda AV - public EP - 33 ER - TY - RPRT ID - soton19182 UR - https://eprints.soton.ac.uk/19182/ Y1 - 2001/12// PB - International CLIVAR Project Office T3 - 58 KW - CLIVAR KW - WCRP KW - Atlantic M1 - project_report TI - Report of the Third Session of the CLIVAR Atlantic Implementation Panel AV - public EP - 20 ER - TY - RPRT ID - soton19186 UR - https://eprints.soton.ac.uk/19186/ Y1 - 2001/01// PB - International CLIVAR Project Office T3 - 38 KW - clivar KW - wcrp KW - atlantic M1 - project_report TI - Report of the 2nd meeting of the CLIVAR Atlantic Implementation Panel, 1-2 December 2000, Orense, Spain AV - public EP - 17 ER - TY - JOUR ID - soton8714 UR - https://eprints.soton.ac.uk/8714/ IS - 3/4 A1 - Aiken, J. A1 - Rees, N. A1 - Hooker, S. A1 - Holligan, P. A1 - Bale, A. A1 - Robins, D. A1 - Moore, G. A1 - Harris, R. A1 - Pilgrim, D. Y1 - 2000/// N2 - The Atlantic Meridional Transect programme uses the twice-annual passage of the RRS James Clark Ross between the UK and the Falkland Islands, before and after the Antarctic research programme in the Austral Summer (see Aiken, J., & Bale, A. J. (2000). An introduction to the Atlantic Meridional Transect (AMT) Programme. Progress in Oceanography, this issue). This paper examines the scientific rationale for a spatially-extensive time and space series programme and reviews the relevant physical and biological oceanography of the Atlantic Ocean. The main scientific observations from the research programme are reported. These are set in the context of historical and contemporary observations pertinent to the principal objectives of the cruise, notably the satellite remotely sensed observations of ocean properties. The extent to which the programme goals have been realised by the research to date is assessed and discussed. New bio-optical signatures, which can be related to productivity parameters, have been derived. These can be used to interpret remotely sensed observations of ocean colour in terms of productivity and production processes such as the air/sea exchange of biogenic gases, which relate to the issues of climate change and the sustainability of marine ecosystems. JF - Progress in Oceanography VL - 45 KW - AMT KW - RESEARCH PROGRAMMES KW - ATLANTIC MERIDIONAL TRANSECT KW - ATLANTIC OCEAN KW - CTD OBSERVATIONS KW - OCEANOGRAPHIC DATA KW - OPTICAL PROPERTIES KW - REMOTE SENSING KW - SEAWIFS KW - PIGMENTS KW - PRIMARY PRODUCTION SN - 0079-6611 TI - The Atlantic Meridional Transect: overview and synthesis of data SP - 257 AV - none EP - 312 ER - TY - JOUR ID - soton69763 UR - https://eprints.soton.ac.uk/69763/ IS - 1-2 A1 - Aksenov, Yevgeny A1 - Bacon, Sheldon A1 - Coward, Andrew C. A1 - Nurser, A.J. George Y1 - 2010/01// N2 - North Atlantic Water (NAW) plays a central role in the ocean climate of the Nordic Seas and Arctic Ocean. Whereas the pathways of the NAW in the Nordic Seas are mostly known, those into the Arctic Ocean are yet to be fully understood. To elucidate these routes the results of a high-resolution global coupled ice?ocean model are used. We demonstrate that in 1989?2004 the NAW inflow was equally divided between the Fram Strait and Barents Sea. We find that salt influx within the branches is comparable but that most of the heat entered the Arctic Ocean through Fram Strait. The model shows complex NAW circulation patterns in the Barents Sea. Two mode waters in the Barents Sea branch are identified: a halocline water produced by surface cooling at shallow convective sites in the northern Barents Sea, and bottom water formed from NAW in the southeastern Barents Sea via full-depth convection and mixing. These two modes continue into the Nansen Basin along two separate routes: one through the northern Barents Sea shelf, and the other through the southeastern Barents Sea with halocline mode water dominating the outflow. Overall, less than half of the NAW coming into the Nordic Seas reaches the Arctic Ocean relatively unmodified, and the rest of it will have been modified in the Barents and Kara Seas with a large fraction re-circulating into the North Atlantic.

JF - Journal of Marine Systems VL - 79 KW - Arctic Ocean KW - Nordic Seas KW - North Atlantic Water KW - Ocean modelling KW - Oceanic transports KW - Water mass transformation SN - 0924-7963 TI - The North Atlantic inflow to the Arctic Ocean: high-resolution model study SP - 1 AV - none EP - 22 ER - TY - JOUR ID - soton439687 UR - https://eprints.soton.ac.uk/439687/ IS - 2 A1 - Almodóvar, Ana A1 - Nicola, Graciela G A1 - Ayllón, Daniel A1 - Trueman, Clive N A1 - Davidson, Ian A1 - Kennedy, Richard A1 - Elvira, Benigno Y1 - 2020/03/01/ N2 -

Historical data on the oceanic distribution and migration routes of southernmost Atlantic salmon Salmo salar populations from Europe are almost non-existent, as no rigorous tagging initiatives have been conducted. Here, we used stable isotope data (? 13C and ? 15N) of historic scale collections to identify the potential marine feeding areas of the largest salmon population in the Iberian Peninsula. Data were compared with published datasets from Northern Ireland, Wales, south England, and northeast UK coast, which correspond to series between 15-and 33-year long within the time period from 1958 to 2009. Temporal covariation in sea surface temperature, primary productivity, and ? 13C values suggests that feeding areas of Iberian salmon are located around Greenland, both in the Labrador and the Irminger seas. Furthermore, ? 13C values of Atlantic salmon from Canadian rivers reported in the literature are similar to those found in individuals from Spanish rivers. Our results suggest that Iberian salmon follow a westerly migration route towards Greenland instead of following the easterly branch of the North Atlantic current into the Norwegian Sea. Characterization of feeding patterns and migration routes might help to understand the causes of ongoing population decline and establish targeted conservation programmes for threatened Iberian salmon.

JF - ICES Journal of Marine Science VL - 77 KW - North Atlantic KW - Salmo salar KW - migration KW - scales KW - time series SN - 1054-3139 TI - Stable isotopes suggest the location of marine feeding grounds of South European Atlantic salmon in Greenland SP - 593 AV - public EP - 603 ER - TY - JOUR ID - soton360969 UR - https://eprints.soton.ac.uk/360969/ A1 - Alt, Claudia H.S. A1 - Rogacheva, Antonina A1 - Boorman, Benjamin A1 - Hughes, Alan J. A1 - Billett, David S.M. A1 - Gooday, Andrew J. A1 - Jones, Daniel O.B. Y1 - 2013/12/15/ N2 - We investigated the effects of contrasting surface primary production on the benthic invertebrate megafauna at four sites on the Mid-Atlantic Ridge. The sites, designated NW, NE, SW and SE, were located to the west and east of the Ridge axis and to the north and south of the Charlie?Gibbs Fracture Zone. Benthic megafauna were sampled in 2007 and 2009 with a semi-balloon otter trawl, at a target depth of 2,500 m. The total biomass and density of major taxonomic groups did not differ significantly between sites, despite those to the north being characterised by greater surface productivity than those to the south. However, the density and biomass of individual taxonomic groups, as well as diversity and body size, all showed significant differences between sites. Diversity was highest at the SE, and lowest at the NE site. Most species were larger to the north. Community composition was significantly different between all sites, with the greatest number of unique species found at the SE, and noticeably fewer unique species at the northern sites. There was no clear correlation between the surface productivity and community structure, suggesting complex ecological controls on the communities. It is speculated that, in addition to the energy supply, drivers such as strong currents and sediment characteristics, play an important role in shaping the communities at the different sites. To what extent the ridge acts as a dispersal barrier for benthic invertebrate fauna remains unclear. However, high numbers of species unique to the southern site suggest a limited dispersal between the northern and southern areas. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 98 KW - Benthic megafauna KW - Diversity KW - Community composition KW - Size KW - ECOMAR KW - Mid-Atlantic Ridge KW - Charlie?Gibbs Fracture Zone SN - 0967-0645 TI - Trawled megafaunal invertebrate assemblages from bathyal depth of the Mid-Atlantic Ridge (48°?54°N) SP - 326 AV - none EP - 340 ER - TY - JOUR ID - soton35593 UR - https://eprints.soton.ac.uk/35593/ IS - 3-4 A1 - Altenbach, A.V. A1 - Lutze, G. A1 - Schiebel, R. A1 - Schonfeld, J. Y1 - 2003/// N2 - Living and dead benthic foraminiferal assemblages from two size fractions, 63?250 ?m and >250 ?m, were studied at 128 stations from the shelves down to abyssal plains of the Gulf of Guinea in the eastern equatorial Atlantic. The sample size ranged between 300 and 400 cm2 of the sediment/water interface, with a penetration depth of 1 cm. Environmental parameters were quantified for sediment composition, food webs, bottom-water oxygen concentrations, and benthic oxygen respiration. Seven major station groupings (named G1?G7) are subdivided by factor analysis. The three most abundant species therein are discussed with respect to their ecological requirements, for both size classes and for living and dead counts. For 49 living species, the range of environmental gradients is established, and for five species live observations are reported. Five station groupings can be attributed toward stepwise ranges scaled by bathymetry and flux rates of organic carbon (G4, 27?75 m; G5, 68?269 m; G6, 250?740 m; G2, 674?2007 m; G1, 1475?4970 m). Two geographically restricted station groupings locally interfinger with other groupings in the upper bathyal and abyssal water depths (G7, 82?451 m; G3, 1002?4658 m). G7 shows lowered oxygen concentrations and benthic oxygen respirations, whereas hemipelagic sediments are typical of G3. The interfingering of G7 and G3, however, is not purely a result of the increasing number of species most perfectly adapted to these environments but rather that these groupings are structured by the decrease of species with lower tolerance towards environmental perturbation. In fact, the more common species have an environmental range much broader than the environmental frame of the groupings they dominate. This observation holds for all size classes and for live and dead counts. We conclude that species-specific preferences and thresholds provide a more valuable and more consistent tool in environmental research than the environmental ranges observed for assemblages.
JF - Palaeogeography, Palaeoclimatology, Palaeoecology VL - 197 KW - eastern equatorial Atlantic KW - shelf KW - slope KW - deep sea KW - environment KW - neontology SN - 0031-0182 TI - Impact of interrelated and interdependent ecological controls on benthic foraminifera: an example from the Gulf of Guinea SP - 213 AV - none EP - 238 ER - TY - JOUR ID - soton6104 UR - https://eprints.soton.ac.uk/6104/ IS - 2 A1 - Alvarez, M. A1 - Bryden, H.L. A1 - Perez, F.F. A1 - Rios, A.F. A1 - Roson, G. Y1 - 2002/// N2 - A transoceanic hydrographic section across the North Atlantic Subpolar gyre from Vigo (northwestern Iberian Peninsula) to Cape Farewell (south of Greenland) was sampled in summer 1997 as part of the World Ocean Circulation Experiment program (WOCE A25, 4x cruise). The circulation pattern across the 4x section is diagnosed using inverse methods. The flow is constrained with measured mass transports at specific sites, while conserving mass and salt for the region north of the section and forcing the silicate flux to a reasonable value. The fluxes of physical (heat and freshwater) and chemical (nutrients and oxygen) properties are estimated and decomposed into barotropic, baroclinic and horizontal components. The heat transport amounts to 0.65 ± 0.1 PW poleward, with 54% and 45% of the flux due to the baroclinic (or overturning) and horizontal circulation, respectively. From the salt conservation, an equatorward freshwater transport of-0.4 ± 1.5 Sv is estimated, resulting from net precipitation plus runoff over the North Atlantic Ocean north of the section. The Subpolar gyre exports nutrients and oxygen southward toward the Subtropical ocean at rates of -50 ± 19, -6 ± 2, -26 ± 15 and -1992 ± 440 kmol s-1 for nitrate, phosphate, silicate and oxygen, respectively. The main mechanism responsible for the nutrient transport is the overturning cell, whereas oxygen is mainly transported southward due to the large-scale horizontal circulation. Combining our fluxes with those from the 36N section (Rintoul and Wunsch, 1991) allows us to examine budgets of physical (heat and freshwater) and chemical (nitrogen and oxygen) properties for an enclosed area of the Subpolar and Temperate North Atlantic. The tentative nitrogen budget for the box between the 4x and the 36N sections suggests that the Temperate North Atlantic is exporting organic nitrogen toward the Subtropical and the Subpolar provinces, which is consistent with indirect evidence. JF - Journal of Marine Research VL - 60 KW - NORTH ATLANTIC KW - ATLN KW - CIRCULATION PATTERNS KW - HEAT FLUX KW - FRESHWATER FLUX KW - NITROGEN CYCLE KW - OXYGEN SN - 0022-2402 TI - Physical and biogeochemical fluxes and net budgets in the subpolar and temperate North Atlantic SP - 191 AV - none EP - 226 ER - TY - JOUR ID - soton19093 UR - https://eprints.soton.ac.uk/19093/ IS - C9 A1 - Alvarez, M. A1 - Perez, F.F. A1 - Shoosmith, D.R. A1 - Bryden, H.L. Y1 - 2005/// N2 - A three-sided box, MedBox, comprising the Strait of Gibraltar, 24°?41°N east of 22°W, was constructed using hydrographic and chemical data from three World Ocean Circulation Experiment cruises in 1997?1998. An extended optimum multiparameter (OMP) analysis resolves the water mass structure in the MedBox. The mass transport is estimated from data and models warranting mass conservation and no deep water formation within the region. Combining the mass transport, the OMP analysis, and the spatial distribution of anthropogenic carbon (CANT), some relevant questions about the Mediterranean Water (MW) formation, transport, and role in the global CO2 cycle are resolved. MW is produced at a rate of 2.7 ± 0.2 Sv in the eastern North Atlantic. It entrains 2.3 Sv of central waters during its formation, including also remnants of Antarctic Intermediate Water. The main advection route of MW is northward, close to the Iberian margin (2.2 Sv), while about 0.5 Sv are exported into the subtropical eastern North Atlantic. The eastern North Atlantic within the MedBox is a strong region of air-sea CANT uptake, 0.7 ± 0.7 mmol m-2 d-1, where CANT is accumulated at a rate of 66 ± 21 kmol s-1 (0.025 GtC yr-1), 17% are taken up through the air-sea interface, and the rest is advected into the area by the circulation. The entrainment of central waters to form MW drives a drawdown of 151 ± 14 kmol s-1 (0.06 GtC yr-1) from the surface to intermediate levels, and 88 ± 8 kmol s-1 (0.03 GtC yr-1) are exported with MW into the North Atlantic, mainly by the horizontal/eddy circulation. JF - Journal of Geophysical Research: Oceans VL - 110 KW - eastern North Atlantic KW - mixing analysis KW - circulation KW - anthropogenic carbon KW - Mediterranean Water TI - Unaccounted role of Mediterranean Water in the drawdown of anthropogenic carbon AV - none ER - TY - JOUR ID - soton2217 UR - https://eprints.soton.ac.uk/2217/ IS - 1 A1 - Alvarez, M. A1 - Rios, A.F. A1 - Perez, F.F. A1 - Bryden, H.L. A1 - Roson, G. Y1 - 2003/// N2 - Transports of Total Inorganic Carbon (TIC), Total Alkalinity (TA) and Anthropogenic Carbon (CANT) are calculated across a densely sampled World Ocean Circulation Experiment (WOCE) section at the southern boundary of the subpolar North Atlantic (WOCE A25, 4x cruise). The circulation pattern was approximated using an inverse model constrained with measured mass transports at specific sites, while conserving the mass and salt transports, and forcing the silicate flux to equal the river input north of the section. The mass and chemical fluxes are decomposed into their barotropic, baroclinic and horizontal components. The TA transport is negligible (transport ± maximum estimate of uncertainty, ~135 ± 507 kmol s-1), while TIC is transported southwards (?1015 ± 490 kmol s?1) and CANT northwards (116 ± 125 kmol s-1). Combining our results with those from Rosón et al. [2002] across 24.5°N (WOCE A5) we examine the contemporary and preindustrial TIC budgets in the subpolar and temperate North Atlantic based on two different approximations for the budget definitions. Initially, river input, biological production of TIC, along with sedimentation of calcium carbonate are ignored. Then, extended contemporary and preindustrial TIC budgets are discussed including rough estimates of the former processes, mainly based on values from the literature. Our findings point to the North Atlantic Ocean north of 24.5°N as a strong sink for atmospheric CO2 both today (2932 ± 2057 kmol s-1) and preindustrially (2439 ± 1721 kmol s-1). Only 17% of the contemporary CO2 air-sea uptake corresponds to CANT, which is mainly taken up in the temperate North Atlantic (between the 4x and 24.5°N sections). North of 24.5°N the Atlantic Ocean stores CANT at a rate of 1123 ± 200 kmol s-1. This CANT is mainly advected into the area in the upper limb of the overturning circulation, while 44% is directly introduced by air-sea uptake. JF - Global Biogeochemical Cycles VL - 17 KW - North Atlantic KW - transports and budgets of inorganic carbon KW - transport and storage of anthropogenic carbon KW - air-sea CO2 fluxes. SN - 0886-6236 TI - Transports and budgets of total inorganic carbon in the subpolar and temperate North Atlantic AV - none ER - TY - JOUR ID - soton67567 UR - https://eprints.soton.ac.uk/67567/ IS - 10 A1 - Amaro, Teresa A1 - Witte, Harry A1 - Herndl, Gerhard J. A1 - Cunha, Marina R. A1 - Billett, David S.M. Y1 - 2009/10// N2 - Deposit-feeding holothurians often dominate the megafauna in bathyal deep-sea settings, in terms of both abundance and biomass. Molpadia musculus is particularly abundant at about 3400 m depth in the Nazaré Canyon on the NE Atlantic Continental Margin. However, these high abundances are unusual for burrowing species at this depth. The objective of this research was to understand the reasons of the massive occurrence of these molpadiid holothurians in the Nazaré Canyon. To address this question we investigated possible trophic interactions with bacteria at sites where the organic content of the sediment was different (Setúbal and Cascais Canyons, NE Atlantic Continental Margin). The molecular fingerprinting technique of Denaturing Gradient Gel Electrophoresis (DGGE) with band sequencing, combined with non-metric multi-dimensional scaling and statistical analyses, was used to compare the bacterial community diversity in canyon sediments and holothurian gut contents. Our results suggest that M. musculus does not need to develop a specialised gut bacterial community to aid digestion where the sediment is rich in organic matter (Nazaré Canyon); in contrast, such a community may be developed where the sediment is poorer in organic matter (Cascais Canyon).
JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 56 KW - Molpadia musculus KW - Holothurian KW - Bacteria KW - Portuguese Canyons KW - DGGE KW - NE Atlantic SN - 0967-0637 TI - Deep-sea bacterial communities in sediments and guts of deposit-feeding holothurians in Portuguese canyons (NE Atlantic) SP - 1834 AV - none EP - 1843 ER - TY - JOUR ID - soton357258 UR - https://eprints.soton.ac.uk/357258/ A1 - Andersson, Andreas J. A1 - Krug, Lilian A. A1 - Bates, Nicholas R. A1 - Doney, Scott C. Y1 - 2013/07// N2 - The uptake of atmospheric carbon dioxide (CO2) into the mid-latitudes of the North Atlantic Ocean through the production of wintertime Sub-Tropical Mode Water (STMW) also known as Eighteen Degree Water (EDW) is poorly quantified and constrained. Nonetheless, it has been proposed that the EDW could serve as an important short-term sink of anthropogenic CO2. The objective of the present investigation was to determine sea?air CO2 gas exchange rates and seawater CO2 dynamics during wintertime formation of EDW in the North Atlantic Ocean. During 2006 and 2007, several research cruises were undertaken as part of the CLIMODE project across the northwest Atlantic Ocean with the intent to study the pre-conditioning, formation, and the evolution of EDW. Sea?air CO2 exchange rates were calculated based on measurements of atmospheric pCO2, surface seawater pCO2 and wind speed with positive values denoting a net flux from the surface ocean to the atmosphere. Average sea?air CO2 flux calculated along cruise tracks in the formation region equaled ?18±6 mmol CO2 m?2 d?1 and ?14±9 mmol CO2 m?2 d?1 in January of 2006 and March of 2007, respectively. Average sea?air CO2 flux in newly formed outcropping EDW in February and March of 2007 equaled ?28±10 mmol CO2 m?2 d?1. These estimates exceeded previous flux estimates in this region by 40?185%. The magnitude of CO2 flux was mainly controlled by the observed variability in wind speed and ?pCO2 with smaller changes owing to variability in sea surface temperature. Small but statistically significant difference (4.1±2.6 ?mol kg?1) in dissolved inorganic carbon (DIC) was observed in two occurrences of newly formed EDW in February and March of 2007. This difference was explained either by differences in the relative contribution from different water masses involved in the initial formation process of EDW or temporal changes owing to sea?air CO2 exchange (?25%) and vertical and/or lateral mixing (?75%) with water masses high in DIC from the cold side of the Gulf Stream and/or from below the permanent thermocline. Based on the present estimate of sea?air CO2 flux in newly formed EDW and a formation rate of 9.3 Sv y (Sverdrup year=106 m3 s?1 flow sustained for 1 year), CO2 uptake by newly formed EDW may constitute 3?6% of the total North Atlantic CO2 sink. However, advection of surface waters that carry an elevated burden of anthropogenic CO2 that are transported to the formation region and transformed to mode water may contribute additional CO2 to the total net uptake and sequestration of anthropogenic CO2 to the ocean interior. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 91 KW - Carbon dioxide KW - Sea?air CO2 flux KW - Gas exchange KW - Sub-Tropical Mode Water KW - STMW KW - Eighteen degree water KW - EDW KW - North Atlantic Ocean SN - 0967-0645 TI - Sea?air CO2 flux in the North Atlantic subtropical gyre: Role and influence of Sub-Tropical Mode Water formation SP - 57 AV - none EP - 70 ER - TY - JOUR ID - soton49659 UR - https://eprints.soton.ac.uk/49659/ IS - 1 A1 - Angel, M. A1 - Blachowiak-Samolyk, K. A1 - Drapun, I. A1 - Castillo, R. Y1 - 2007/09// N2 - A large database representing the bathymetric distribution of 117 species of halocyprid ostracods has been compiled from seven stations forming a transect from the equator to 60°N along 20°W, plus an additional station at 32°N, 65°W. This data base is analysed to examine the latitudinal and bathymetric changes in species composition and diversity of assemblages of this important, yet neglected, holoplanktonic group. At each station stratified sampling of the complete water column from the surface down mostly to 2000 m was carried out both day and night. Each sample resulted from the filtration of at least 2500 m3 of water and was analysed using a consistent protocol. The differences between the day and night profiles are attributable to diel vertical migrations, to local-scale heterogeneity, and possibly to a degree of net avoidance. There is a gradient of increasing species richness and diversity from high to low latitudes. By day, halocyprids are either infrequent or absent from the upper 50 m of the water column, but at night after diel vertical migration they become quite abundant in the epipelagic zone, particularly at low latitudes. Bathymetric profiles show ostracod abundances increase rapidly below the thermocline, reaching maxima at 200?400 m and then declining by at least an order of magnitude at 2000 m. Diversity (both species richness, H? and evenness, J) also increases below the thermocline and thereafter is either maintained or declines only slightly to 2000 m. There are no relationships among diversity, abundance and productivity, but analysis of the whole database shows that the changes in community structure are consistent with Longhurst?s [Longhurst, A.R., 1998. Ecological Geography of the Sea. Academic Press, San Diego, pp. xiv, 398.] biogeochemical provinces. JF - Progress in Oceanography VL - 73 KW - North Atlantic KW - Zoogeography KW - Diversity KW - Zooplankton KW - Ostracoda KW - Bathymetry SN - 0079-6611 TI - Changes in the composition of planktonic ostracod populations across a range of latitudes in the North-east Atlantic SP - 60 AV - none EP - 78 ER - TY - JOUR ID - soton352048 UR - https://eprints.soton.ac.uk/352048/ IS - 2 A1 - Angel, Martin A1 - Graves, Carol Y1 - 2013/// N2 - Species of the genera Bathyconchoecia and Scottoecia are currently classified in the subfamily Euconchoeciinae together with species of the genus Euconchoecia. The morphological and ecological characteristics of many of the species currently attributable to these two taxa are compared with a range of Euconchoecia species and are shown to differ extensively. These differences are sufficient to separate these taxa at the subfamily level. Therefore, a new subfamily, the Bathyconchoeciinae is proposed to accommodate all the species currently classified in the genera Bathyconchoecia and Scottoecia. JF - Zootaxa VL - 3630 KW - Myodocopa KW - Euconchoecia KW - Bathyconchoecia KW - Scottoecia KW - systematics KW - oceanic KW - abyssopelagic KW - morphology KW - Atlantic KW - Euconchoeciinae SN - 1175-5334 TI - Bathyconchoeciinae, a new subfamily of deep oceanic planktonic halocyprid Ostracod (Myodocopa, Ostracoda) SP - 243 AV - none EP - 269 ER - TY - JOUR ID - soton2161 UR - http://iris.ingentaselect.com/vl=2361897/cl=38/nw=1/rpsv/cw/jmr/00222402/v60n6/s4/p835 IS - 6 A1 - Anschutz, P. A1 - Jorissen, F.J. A1 - Chaillou, G. A1 - Abu-Zied, R. A1 - Fontanier, C. Y1 - 2002/// N2 - An interface core taken in Capbreton canyon shows a succession of sedimentary facies interpreted as classical Bouma turbiditic sequences. Activities of 234Th and 210Pb suggest that the deposition of the most recent turbidite was triggered by the violent storm that affected the Atlantic coast of southern France on the 27th of December 1999, about four months before the sampling of the core. This turbidite allows us to study the ongoing diagenesis of the new sediment layer and of the previous sediment-water interface, which has been buried and only slightly eroded. A study of benthic foraminiferal populations informs us about the rate of benthic ecosystem recovery after such a major ecosystem disturbance event. The composition of the benthic foraminiferal fauna suggests that the benthic ecosystem in Capbreton canyon remains in an early stage of colonization. The rare agglutinant taxon Technitella melo appears to be the first colonizing species. It is suggested that Technitella melo is advantaged by the food-impoverished conditions in the days following turbidite deposition. Almost all of the turbidite layer and the previous oxic sediment-water interface contain reduced dissolved metal species and were anoxic. The buried interface contains Fe- and Mn-oxides inherited from its recent oxic past. The reduction of manganese oxides was in progress at the time of core collection. The reduced Mn remained trapped in the sediment as Mn-containing carbonates. Iron-oxides did not undergo significant reductive dissolution. The top of the newly deposited turbidite formed an oxic layer, which was rapidly enriched in metal-oxides. The enrichment of manganese oxides was mostly due to the oxidation of dissolved Mn2+, which diffused from below. The enrichment of iron oxides is explained both by the oxidation of the upward flux of dissolved Fe2+, and by the input of detrital iron oxide after, or as a result of the turbidite deposition. JF - Journal of Marine Research VL - 60 KW - TURBIDITES KW - ATLANTIC OCEAN KW - DIAGENESIS KW - THORIUM ISOTOPES KW - LEAD ISOTOPES KW - SEDIMENT GRAVITY FLOWS SN - 0022-2402 TI - Recent turbidite deposition in the eastern Atlantic: early diagnesis and biotic recovery SP - 835 AV - none EP - 854 ER - TY - JOUR N1 - Funding Information: French Ministry of Higher Education, Research and Innovation (MESRI) public funding awarded to Lise Artigue (University of Toulouse). Funding Information: French National Centre for Scientific Research (CNRS) public funding awarded to François Lacan (LEGOS). Publisher Copyright: © 2020 Elsevier Ltd ID - soton438740 UR - https://eprints.soton.ac.uk/438740/ A1 - Artigue, Lise A1 - Lacan, François A1 - Van Gennip, Simon A1 - Lohan, Maeve C. A1 - Wyatt, Neil J. A1 - Woodward, E. Malcolm S. A1 - Mahaffey, Claire A1 - Hopkins, Joanne A1 - Drillet, Yann Y1 - 2020/04// N2 - This study presents a water mass analysis along the JC150 section in the subtropical North Atlantic, based on hydrographic and nutrient data, by combining an extended optimum multiparameter analysis (OMPA) with a Lagrangian particle tracking experiment (LPTE). This combination, which was proposed for the first time, aided in better constraining the OMPA end-member choice and providing information about their trajectories. It also enabled tracing the water mass origins in surface layers, which cannot be achieved with an OMPA. The surface layers were occupied by a shallow type of Eastern South Atlantic Central Water (ESACW) with traces of the Amazon plume in the west. Western North Atlantic Central Water dominates from 100 to 500 m, while the 13 °C-ESACW contribution occurs marginally deeper (500?900 m). At approximately 700 m, Antarctic Intermediate Water (AAIW) dominates the west of the Mid-Atlantic Ridge (MAR), while Mediterranean Water dominates the east with a small but non-negligible contribution down to 3500 m. Below AAIW, Upper Circumpolar Deep Water (UCDW) is observed throughout section (900?1250 m). Labrador Sea Water (LSW) is found centered at 1500 m, where the LPTE highlights an eastern LSW route from the eastern North Atlantic to the eastern subtropical Atlantic, which was not previously reported. North East Atlantic Deep Water (encompassing a contribution of Iceland-Scotland Overflow Water) is centered at ~2500 m, while North West Atlantic Bottom Water (NWABW, encompassing a contribution of Denmark Strait Overflow Water) is principally localized in the west of the MAR in the range of 3500?5000 m. NWABW is also present in significant proportions (>25%) in the east of the MAR, suggesting a crossing of the MAR possibly through the Kane fracture zone. This feature has not been investigated so far. Finally, Antarctic Bottom Water is present in deep waters throughout the section, mainly in the west of the MAR. Source waters have been characterized from GEOTRACES sections, which enables estimations of trace elements and isotope transport within water masses in the subtropical North Atlantic. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 158 KW - GEOTRACES KW - JC150 KW - Lagrangian particle tracking experiment KW - Optimum multiparameter analysis (OMPA) KW - Subtropical north Atlantic KW - Water mass SN - 0967-0637 TI - Water mass analysis along 22 °N in the subtropical North Atlantic for the JC150 cruise (GEOTRACES, GApr08) AV - public ER - TY - JOUR N1 - Funding Information: The authors thank K. Kunde and D. G. Santana for sampling alongside the Captain and crew of the RRS James Cook during GApr08. The authors thank J. Gaillardet for his help about the Lesser Antilles erosion and weathering. The authors thank J. K. Klar for the GA06 dAl data and for the helpful scientific discussion. The authors thank A. Carret for the help with MATLAB. The authors thank J. D. Milliman, R. Middag, and K. Kunde for the helpful scientific discussion. The authors thank the reviewers of this study, one anonymous, and J. Resing for constructive comments that helped improve the manuscript. The French Ministry of Higher Education, Research and Innovation (MESRI) funded through the University Toulouse III the Ph.D. fellowship of L. Artigue. The French National Centre for Scientific Research (CNRS) funded F. Lacan. NERC funded C. Mahaffey (NE/N001979/1) and M.C. Lohan (NE/N001125/1). Funding Information: The authors thank K. Kunde and D. G. Santana for sampling alongside the Captain and crew of the RRS James Cook during GApr08. The authors thank J. Gaillardet for his help about the Lesser Antilles erosion and weathering. The authors thank J. K. Klar for the GA06 dAl data and for the helpful scientific discussion. The authors thank A. Carret for the help with MATLAB. The authors thank J. D. Milliman, R. Middag, and K. Kunde for the helpful scientific discussion. The authors thank the reviewers of this study, one anonymous, and J. Resing for constructive comments that helped improve the manuscript. The French Ministry of Higher Education, Research and Innovation (MESRI) funded through the University Toulouse III the Ph.D. fellowship of L. Artigue. The French National Centre for Scientific Research (CNRS) funded F. Lacan. NERC funded C. Mahaffey (NE/N001979/1) and M.C. Lohan (NE/N001125/1). Publisher Copyright: © 2021. American Geophysical Union. All Rights Reserved. ID - soton450680 UR - https://eprints.soton.ac.uk/450680/ IS - 5 A1 - Artigue, Lise A1 - Wyatt, Neil J. A1 - Lacan, François A1 - Mahaffey, Claire A1 - Lohan, Maeve C. Y1 - 2021/05/08/ N2 -

New dissolved aluminum (dAl) data from the 2017 GEOTRACES process study GApr08 along 22°N in the subtropical North Atlantic are presented. They show an east to west increase in dAl concentration in the surface waters. Simulation of these data with a 1D advection-dust deposition revealed that, (a) advection and dust dissolution are equally important dAl sources, (b) scavenging plays a minor role compared to advection in dAl removal, and (c) in addition to dust dissolution, another dAl source is required at the westernmost stations to fully explain our observations. We attribute this additional source to the dissolution of erosion products delivered to the western subtropical North Atlantic by the Lesser Antilles. For waters deeper than ?200?300 m, an optimum multi-parameter analysis allowed to separate the component of the dAl signal derived from water mass transport from its biogeochemical component. This revealed, (a) a major role played by water mass transport, (b) a net dAl removal between 200 and 800 m, attributed to scavenging at the subtropical North Atlantic scale, and (c) internal dAl inputs between 800 m and the seafloor, attributed to reversible scavenging. While the dAl oceanic distribution is usually considered to be dominated by the atmospheric dust input and removal by particle scavenging, this study highlights the important role played by advection, and the need to explicitly take this into account in order to quantitatively reveal the impact of external sources and dissolved-particulate interactions on the Al cycle in the North Atlantic Ocean.

JF - Global Biogeochemical Cycles VL - 35 KW - GEOTRACES KW - OMPA KW - dissolved aluminum KW - geochemical modeling KW - reversible scavenging KW - subtropical North Atlantic SN - 0886-6236 TI - The importance of water mass transport and dissolved?particle interactions on the aluminum cycle in the subtropical North Atlantic AV - public ER - TY - JOUR N1 - Funding Information: We thank Dr Ellen Kenchington (Bedford Institute of Oceanography, Canada) for providing the Canadian and Spanish fishery research survey trawl data required for the kernel density estimation analysis of VME-indicator taxa distributions. This study was undertaken as part of the "NAFO potential vulnerable marine ecosystems-impacts of deep-sea fisheries" (NEREIDA) programme, which is supported by Spain's General Secretary of the Sea, Spain's Ministry for the Rural and Marine Environment, the Spanish Institute of Oceanography, the Geological Survey of Canada, the Canadian Hydrographic Service, Fisheries and Oceans Canada, the United Kingdom's Centre for the Environment Fisheries and Aquaculture Science, the Russian Polar Research Institute of Marine Fisheries and Oceanography, and the Russian P.P. Shirshov Institute of Oceanology. We thank the crew and scientists aboard the Spanish research vessel Miguel Oliver who collected the box core samples analysed in this study. We are grateful to the two reviewers and the editor AG for generously providing their time and offering insightful, constructive comments. ID - soton433678 UR - https://eprints.soton.ac.uk/433678/ A1 - Ashford, Oliver S. A1 - Kenny, Andrew J. A1 - Barrio Froján, Christopher R.S. A1 - Downie, Anna Leena A1 - Horton, Tammy A1 - Rogers, Alex D. Y1 - 2019/07/11/ N2 - Vulnerable marine ecosystems (VMEs) are considered hotspots of biodiversity and ecosystem functioning in the deep sea, but are also characterised by a high vulnerability to disturbance and a low recovery potential. Since 2006, a series of United Nations General Assembly (UNGA) resolutions have been developed, attempting to ensure the protection of VMEs in international waters. In the Northwest Atlantic Fisheries Organisation (NAFO) Regulatory Area, large areas of seabed have been closed to bottom-contact fishing to protect VMEs. However, knowledge of the influence of VME-indicator taxa on macrofaunal assemblages, and the appropriateness of current fishery closures for protecting macrofaunal biodiversity in this area is limited. Here we investigate relationships between the prevalence of VME-indicator taxa [poriferans (sponges), gorgonian corals, and pennatulaceans (sea pens)] and an extensive suite of peracarid crustacean biodiversity metrics in the NAFO Regulatory Area. We also examine whether the current NAFO VME closures protect areas of significantly elevated peracarid diversity. Of the VME-indicator taxa analysed, poriferans were found to have by far the greatest influence over peracarid assemblages. Assemblage structure was altered, and peracarid abundance, biomass, richness, diversity, and variability were enhanced in areas of elevated poriferan biomass, whilst assemblage evenness was slightly depressed in these areas. These findings reaffirm the perception of poriferans as crucial components of VMEs. In contrast, gorgonian coral density had little influence over the faunal assemblages investigated, perhaps reflecting their relatively low prevalence in the study area. Similarly, pennatulaceans were found to influence peracarid assemblages only weakly. This too may reflect a moderately low density of Pennatulacea in the study area. Our results highlight that the application of taxon distribution model outputs to ecological investigations and management decisions in data-limited environments should be treated with caution. Finally, our results indicate that the current system of fishery closures in the NAFO Regulatory Area may not be optimal in terms of providing adequate protection to VMEs against the impacts of bottom trawling. JF - Frontiers in Marine Science VL - 6 KW - coral KW - macrofauna KW - Northwest Atlantic Fisheries Organisation KW - peracarida KW - porifera KW - Species distribution modelling KW - deep sea KW - vulnerable marine ecosystem SN - 2296-7745 TI - On the influence of vulnerable marine ecosystem habitats on peracarid crustacean assemblages in the Northwest Atlantic Fisheries Organisation regulatory area AV - public EP - 14 ER - TY - RPRT ID - soton42442 UR - https://eprints.soton.ac.uk/42442/ A1 - Bacon, S. Y1 - 2006/// N2 - This report describes scientific activities during RRS Discovery cruise 298 in the vicinity of Cape Farewell, southern Greenland, during early autumn 2005. A Deep Western Boundary Current array of seven moorings was deployed, and two IFREMER moorings were recovered, serviced and redeployed; also, a WHOI mooring was recovered. Hydrographic work comprised an area survey of 63 CTD/LADCP stations; up to 24 water samples were captured on each station for the measurement of salinity, dissolved oxygen, nutrients, CFCs (CFC-11, CFC-12, CFC-113 and CCl4), and oxygen isotope fraction (?18O). Continuous underway measurements comprised: navigation; currents, using ship-mounted ADCPs (75 and 150 kHz); meteorology; sea surface temperature and salinity; 3.5 kHz sub-bottom sediment profiling; and bathymetry. Three sediment cores were obtained. Six floats / drifters were launched. D298 (CFER-1) is a part of the project ?Cape Farewell and Eirik Ridge: Interannual to Millennial Thermohaline Circulation Variability?, funded by the UK Natural Environment Research Council as part of its ?Rapid Climate Change? Directed Research Programme. PB - National Oceanography Centre T3 - 10 KW - ADCP KW - Atlantic Ocean KW - Cape Farewell KW - CFC KW - cruise D298 2005 KW - CTD KW - deep western boundary current KW - Discovery KW - dissolved oxygen KW - Eirik Ridge KW - Lowered ADCP KW - meteorology KW - moorings KW - nutrients KW - oxygen isotopes KW - sediment cores KW - shipboard ADCP KW - sub-bottom profiler M1 - project_report TI - RRS Discovery Cruise 298, 23 Aug-25 Sep 2005. Cape Farewell and Eirik Ridge (CFER-1) AV - public EP - 113 ER - TY - RPRT ID - soton42446 UR - https://eprints.soton.ac.uk/42446/ A1 - Bacon, S. Y1 - 2006/// N2 - This report describes scientific activities during RRS Discovery cruise 309-310 in the vicinity of Cape Farewell, southern Greenland, during late summer 2006. A Deep Western Boundary Current array of seven moorings was recovered and a replacement array of five moorings was deployed. For IFREMER, one mooring and one glider were recovered; one IfM-GEOMAR and three NIOZ moorings were recovered, serviced and redeployed. Hydrographic work comprised 25 CTD/LADCP stations, and three tows of the Moving Vessel Profiler (MVP); water samples were captured on each station for the measurement of salinity. Continuous underway measurements comprised: navigation; currents, using ship-mounted ADCPs (75 and 150 kHz); meteorology; sea surface temperature and salinity; and bathymetry. D309-310 (CFER-2) is a part of the project ?Cape Farewell and Eirik Ridge: Interannual to Millennial Thermohaline Circulation Variability?, funded by the UK Natural Environment Research Council as part of its ?Rapid Climate Change? Directed Research Programme. PB - National Oceanography Centre T3 - 11 KW - ADCP KW - Atlantic Ocean KW - Cape Farewell KW - cruise D309-310 2006 KW - CTD KW - deep western boundary current KW - Discovery KW - Eirik Ridge KW - Lowered ADCP KW - meteorology KW - moorings KW - Moving Vessel Profiler KW - MVP KW - shipboard ADCP M1 - project_report TI - RRS Discovery Cruise 309-310, 18 Aug-05 Sep 2006. Cape Farewell and Eirik Ridge (CFER-2) AV - public EP - 112 ER - TY - JOUR ID - soton2034 UR - https://eprints.soton.ac.uk/2034/ A1 - Bacon, S. Y1 - 2002/// JF - ICES Marine Science Symposia VL - 215 KW - ATLANTIC OCEAN KW - ATLN KW - GREENLAND ICELAND RIDGE KW - NORDIC SEAS KW - OVERFLOW 60 KW - OVERFLOW 73 KW - MONA KW - NANSEN TI - The dense overflows from the Nordic Seas into the deep North Atlantic SP - 148 AV - none EP - 155 ER - TY - RPRT ID - soton306 UR - https://eprints.soton.ac.uk/306/ A1 - Bacon, S. Y1 - 1998/// N2 - This report describes RRS Discovery Cruise 230, designed as a repeat of the International Geophysical Year (IGY) survey section 4, roughly from Cape Finisterre (Spain) to Cape Farewell (Greenland). IGY 4 was first surveyed in 1957, so this repeat gives a 40?year look at decadal variability in the North Atlantic from the eastern boundary regime via the junction of subtropical and subpolar gyres to the western boundary regime. Additional short sections were measured (a) midway between Cape Farewell and Denmark Strait, (b) across Denmark Strait and (c) from Iceland to Scotland in order (i) to assess the spatial variability of the western boundary regime up the east Greenland coast to Denmark Strait, (ii) to assess the exchange between the northern North Atlantic and the Nordic Seas, (iii) to create a large scale North Atlantic closed box for evaluation of the circulation, and (iv) to continue the long time series of Rockall Trough sections. Sections were measured with stations for CTD, LADCP and tracer chemistry (CFCs, oxygen, nutrients, CO2). Continuous measurements of high precision position and heading navigation data were made; also of VM?ADCP, depth and TSG. Continuous high?quality meteorological measurements were made, with a view to assessing Ekman fluxes, and comparing with fluxes inferred from Irminger Basin float data. This cruise is a UK contribution to the World Ocean Circulation Experiment. PB - Southampton Oceanography Centre, University of Southampton T3 - 16 KW - ADCP KW - ATLN KW - carbon dioxide KW - CFC KW - Charlie-Gibbs Fracture Zone KW - CO2 KW - cruise 230 1997 KW - CTD observations KW - Denmark Strait KW - Discovery KW - Iberian Abyssal Plain KW - Iceland Basin KW - International Geophysical Year KW - IGY KW - Irminger Basin KW - LADCP KW - North Atlantic KW - nutrients KW - oxygen KW - Rockall Trough KW - water exchange KW - WOCE M1 - project_report TI - RRS Discovery Cruise 230, 07 Aug-17 Sep 1997. Two hydrographic sections across the boundaries of the subpolar gyre: FOUREX AV - public EP - 104 ER - TY - RPRT ID - soton43302 UR - https://eprints.soton.ac.uk/43302/ Y1 - 2007/01// PB - International CLIVAR Project Office T3 - No. 40 (Vol. 12(1) KW - CLIVAR KW - WCRP KW - ICES KW - climate KW - North Atlantic KW - Exchanges ED - Bacon, S. ED - Holliday, P. ED - Cattle, H. M1 - project_report TI - CLIVAR Exchanges - The Oceanography of the North Atlantic and adjacent Seas AV - public EP - 32 ER - TY - RPRT ID - soton165429 UR - https://eprints.soton.ac.uk/165429/ A1 - Bacon, S. A1 - et al, Y1 - 2010/10// N2 - This report describes scientific activities on RRS Discovery cruise 332, ?Arctic Gateway?, in
the vicinity of WOCE hydrographic section AR7 between Canada, Greenland and Scotland
during late summer 2008. Hydrographic work comprised 74 CTD/LADCP stations and one
tow of the Moving Vessel Profiler. Water samples were captured for on-board measurement of
salinity, dissolved oxygen, inorganic nutrients, calcite, particulate organic carbon and
chlorophyll. Samples were also captured for storage for later on-shore analysis of oxygen
isotope fraction, chlorofluorocarbons, sulphur hexafluoride and alkalinity / total carbon
dioxide. Continuous underway measurements comprised: navigation; currents, using vesselmounted
ADCPs (75 and 150 kHz); meteorology; sea surface temperature and salinity; and
bathymetry. Mooring operations comprised the recovery of two current meter moorings off
Cape Farewell; two other moorings were deemed lost; an instrument from a fifth mooring, not
recovered at the time, was later found intact in west Scotland. Additionally, a party from the
Royal NIOZ were engaged in a programme of recovery and redeployment of Dutch moorings.
UK funding for D332 was provided by the Natural Environment Research Council under its
Oceans2025 programme.
KEYWORDS PB - National Oceanography Centre T3 - 53 KW - ADCP KW - Atlantic Ocean KW - Cape Farewell KW - cruise D309-310 2006 KW - CTD KW - deep western boundarycurrent KW - Discovery KW - Eirik Ridge KW - Lowered ADCP KW - meteorology KW - moorings KW - Moving VesselProfiler KW - MVP KW - shipboard ADCP M1 - project_report TI - RSS Discovery Cruise 332, 21 Aug ? 25 Sep 2008. Arctic Gateway (WOCE AR7) AV - public EP - 129 ER - TY - JOUR ID - soton340006 UR - https://eprints.soton.ac.uk/340006/ IS - 1 A1 - Baczewska, Anna A1 - Blachowiak-Samolyk, Katarzyna A1 - Angel, Martin V. Y1 - 2012/// N2 - Although, pelagic Ostracoda are locally abundant component of the mesozooplankton in the waters around Svalbard, the group remains poorly characterised both taxonomically and ecologically. Herein, the spatial and vertical variations in abundances and species composition of the pelagic osstracoda assemblages are examined and related to the water masses. The study is based on a series of zooplankton samples collected with a multinet plankton sampler (MPS; HydroBios, Kiel), consisting of five nets fitted with a 180- m mesh net. Samples were collected from deep stations (i.e., with bottom depths [300 m) around Svalbard and included localities influenced by the West Spitsbergen Current and the East Spitsbergen Current and to the north of Svalbard, between years 2001 and 2006. Throughout all the samples studied Discoconchoecia elegans was the numerically dominant species. The other species found were Boroecia maxima, Boroecia borealis, Obtusoecia obtusata, and a rare novel Boroecia species. Analyses of the pelagic Ostracoda assemblages showed that their variability was predominantly influenced by four factors: water temperature, geographical position, bottom depth and season. The highest densities of D. elegans were correlated with salinities[35 PSU whereas B. maxima distribution was dependent on latitude. Highest concentrations of B. borealis were determined by longitude. Abundances of O. obtusata were positively correlated with warmer water temperatures. Thus this work suggests that halocyprids have the potential to be good indicators of environmental changes associated with shifts in climate at high latitudes in the North Atlantic. JF - Hydrobiologia VL - 688 KW - factors KW - ? Horizontal and vertical distribution KW - Atlantic Waters SN - 0018-8158 TI - Distribution of pelagic Ostracoda (Crustacea) inhabiting the waters around Svalbard (Arctic Ocean: 76°36?81°50N) SP - 75 AV - none EP - 92 ER - TY - JOUR ID - soton376931 UR - https://eprints.soton.ac.uk/376931/ A1 - Bale, Nicole J. A1 - Airs, Ruth L. A1 - Martin, Patrick A1 - Lampitt, Richard S. A1 - Llewellyn, Carole A. Y1 - 2015/05/20/ N2 - A research cruise in the North Atlantic during the annual diatom bloom provided an ideal platform to study chlorophyll-a (chl-a) transformations associated with a large scale diatom bloom and export below the photic zone. On one deployment, Lagrangian sediment traps captured a significant flux of aggregated diatom cells produced during the termination of the main bloom. We examined the distribution of chl-a transformation products in sinking particles from the sediment traps and in suspended particles from the water column using high-resolution HPLC with multistage mass spectrometry (LC?MSn). There was a dramatic change in the distribution of chl-a and its transformation products between the pre-sinking period, when the average chl-a concentration integrated over the upper 50 m was 68 ± 36 mg m? 2, and the post-sinking period, when it was 30 ± 11 mg m? 2. Before the diatom bloom left the euphotic zone (pre-sinking), suspended particles contained a considerably higher percentage of pheophorbide-a and other chl-a transformation products (27%) than during the post-sinking period (10%). Despite high levels of spatial variability in the chl-a concentration, and despite sampling from both within and outside a main bloom patch, the chl-a transformation products in suspended particles did not exhibit spatial variability. Sinking particles associated with the diatom bloom export had low POC:chl-a ratios (52?97), suggesting undegraded phytoplankton cells. However, the samples with especially low POC:chl-a ratios exhibited similar distributions of chl-a transformation products to those with a higher ratio. The proportions of demetalated and de-esterified transformation products increased with depth of suspended particles, although significant levels of these products were also found in the uppermost 20 m during the bloom. This suggests processes in both surface waters and through the water column led to the formation of these products. JF - Marine Chemistry VL - 172 KW - Chlorophyll-a transformation products KW - Diatom bloom KW - Bloom termination KW - Sinking particles KW - Suspended particles KW - North Atlantic SN - 0304-4203 TI - Chlorophyll-a transformations associated with sinking diatoms during termination of a North Atlantic spring bloom SP - 23 AV - none EP - 33 ER - TY - RPRT ID - soton51297 UR - https://eprints.soton.ac.uk/51297/ A1 - Baringer, M.O. A1 - Kanzow, T. Y1 - 2008/05// N2 - This report describes the mooring operations conducted during RV Ronald H. Brown Cruise RB0701 conducted
between 21 March 2007 and 10 April 2007.
These mooring operations were completed as part of the United Kingdom Natural Environment Research Council
(NERC) funded RAPID Programme to monitor the Atlantic Meridional Overturning Circulation at 26.5ºN. The
primary purpose of this cruise was to service the Western Boundary section of the 26.5ºN mooring array first
deployed in 2004 during RRS Discovery cruises D277 and D278 (SOC cruise report number 53), and serviced in
2005 during RRS Charles Darwin Cruise CD170 and RV Knorr Cruise KN182-2 (NOCS cruise report number 2),
RRS Charles Darwin Cruise CD177 (NOCS cruise report number 5), and in 2006 on RV Ronald H. Brown Cruise
RB0602, RRS Discovery Cruise D304 (NOCS cruise report number 16) and FS Poseidon Cruises P343 and P345
(NOCS cruise report number 28).
Cruise RB0701 was from Charleston, SC to San Juan, Puerto Rico, and covered the Western Boundary moorings
deployed on RB0602 (along with two landers deployed on KN182-2). This cruise is the third annual refurbishment
of the Western Boundary section of an array of moorings deployed across the Atlantic in order to set up a preoperational
prototype system to continuously observe the Atlantic Meridional Overturning Circulation (MOC).
This array will be further refined and refurbished during subsequent years.
The instrumentation deployed on the array consists of a variety of current meters, bottom pressure recorders, CTD
loggers and Inverted Echosounders, which, combined with time series measurements of the Florida Channel
Current and wind stress estimates, will be used to determine the strength and structure of the MOC at 26.5ºN.
(http://www.noc.soton.ac.uk/rapidmoc) PB - National Oceanography Centre T3 - 29 KW - Atlantic Ocean KW - bottom pressure recorder KW - BPR KW - cruise RB0701 2007 KW - CTD KW - current meter KW - Ronald H. Brown KW - Meridional Overturning Circulation KW - MOC KW - mooring array KW - Moorings KW - North Atlantic KW - RAPID KW - RAPIDMOC KW - THC KW - thermohaline circulation ED - Rayner, D. M1 - project_report TI - RV Ronald H. Brown Cruise RB0701, 21 Mar-10 Apr 2007. RAPID mooring cruise report AV - public EP - 60 ER - TY - RPRT ID - soton48093 UR - https://eprints.soton.ac.uk/48093/ A1 - Baringer, M.O. A1 - Kanzow, T. Y1 - 2007/09/26/ N2 - This report describes the mooring operations conducted during RV Ronald H. Brown Cruise RB0602 and RRS Discovery Cruise D304. Cruise RB0602 was conducted between 9 March 2006 and 28 March 2006, and Cruise D304 was conducted between 12 May 2006 and 6 June 2006.

These mooring operations were completed as part of the United Kingdom Natural Environment Research Council (NERC) funded RAPID Programme to monitor the Atlantic Meridional Overturning Circulation at 26.5ºN. The primary purpose of these cruises was to service the 26.5ºN mooring array first deployed in 2004 during RRS Discovery cruises D277 and D278 (SOC cruise report number 53), and serviced in 2005 during RRS Charles Darwin Cruise CD170 and RV Knorr Cruise KN182-2 (NOCS cruise report number 2), and RRS Charles Darwin Cruise CD177 (NOCS cruise report number 5).

Cruise RB0602 was from Barbados to Charleston, SC, and covered the Western Boundary moorings deployed on KN182-2. Cruise D304 was to and from Tenerife and covered the Eastern Boundary and Mid-Atlantic Ridge moorings deployed on cruises CD170 and CD177. These cruises are the second annual refurbishment of an array of moorings deployed across the Atlantic in order to set up a pre-operational prototype system to continuously observe the Atlantic Meridional Overturning Circulation (MOC). Cruise CD177 was an intermediate service cruise to obtain data from the two principal Eastern Boundary moorings six months after deployment. This array will be further refined and refurbished during subsequent years.

The instruments deployed on the array consists of a variety of current meters, bottom pressure recorders, CTD loggers and Inverted Echosounders, which, combined with time series measurements of the Florida Channel Current and wind stress estimates, will be used to determine the strength and structure of the MOC at 26.5ºN. (http://www.noc.soton.ac.uk/rapidmoc)
PB - National Oceanography Centre T3 - 16 KW - Atlantic Ocean KW - bottom pressure recorder KW - BPR KW - cruise RB0602 2006 KW - cruise D304 2006 KW - CTD KW - current meter KW - Discovery KW - Meridional Overturning Circulation KW - MOC KW - mooring array KW - Moorings KW - North Atlantic KW - RAPID KW - RAPIDMOC KW - Ronald H. Brown KW - THC KW - thermohaline circulation KW - Pressure Inverted Echosounder KW - PIES KW - IES ED - Rayner, D. M1 - project_report TI - RV Ronald H. Brown Cruise RB0602 and RRS Discovery Cruise D304, Rapid Mooring Cruise Report March and May 2006 AV - public EP - 165 ER - TY - JOUR ID - soton6000 UR - https://eprints.soton.ac.uk/6000/ IS - 2 A1 - Barker, N.D. A1 - Sinha, M.C. A1 - MacGregor, L.M. A1 - ISO-, 3d Group Y1 - 2001/// JF - InterRidge News VL - 10 KW - HYDROTHERMAL SOLUTIONS. MID ATLANTIC RIDGE KW - ELECTROMAGNETISM TI - Hydrothermal fluids at the Mid-Atlantic Ridge: preliminary results from sub-seafloor electromagnetic sounding SP - 36 AV - none EP - 39 ER - TY - JOUR ID - soton6099 UR - https://eprints.soton.ac.uk/6099/ IS - 4 A1 - Barlow, R.G. A1 - Aiken, J. A1 - Holligan, P.M. A1 - Cummings, D.G. A1 - Maritorena, S. A1 - Hooker, S. Y1 - 2002/// N2 - Pigment patterns and associated absorption properties of phytoplankton were investigated in the euphotic zone along two meridional transects in the Atlantic Ocean, between the UK and the Falkland Islands, and between South Africa and the UK. Total chlorophyll a (TChla=MVChla+DVChla+chlorophyllide a) concentrations and the biomarker pigments for diatoms (fucoxanthin), nanoflagellates and cyanobacteria (zeaxanthin) appeared to have similar distribution patterns in the spring and in the autumn in the temperate NE Atlantic and the northern oligotrophic gyre. Divinyl chlorophyll a levels (prochlorophytes) were greater in spring at the deep chlorophyll maximum in the oligotrophic gyre, however. Marked seasonal differences were observed in the NW African upwelling region. TChla concentrations were twice as high in the upper mixed layer in the spring, with the community dominated by diatoms and prymnesiophytes (19?-hexanoyloxyfucoxanthin). A layered structure was prevalent in the autumn where cyanobacteria, diatoms and prymnesiophytes were located in the upper water column and diatoms and mixed nanoflagellates at the sub-surface maximum. In the South Atlantic, the Benguela upwelling ecosystem and the Brazil-Falklands Current Confluence Zone (BFCCZ) were the most productive regions with the TChla levels being twice as high in the Benguela. Diatoms dominated the Benguela system, while nanoflagellates were the most ubiquitous group in the BFCCZ. Pigment concentrations were greater along the eastern boundary of the southern oligotrophic gyre and distributed at shallower depths. Deep chlorophyll maxima were a feature of the western boundary oligotrophic waters, and cyanobacteria tended to dominate the upper water column along both transects with a mixed group of nanoflagellates at the chlorophyll maximum.
Absorption coefficients were estimated from spectra reconstructed from pigment data. Although absorption was greater in the productive areas, the TChla-specific coefficients were higher in oligotrophic regions. In communities that were dominated by diatoms or nanoflagellates, pigment absorption was generally uniform with depth and attenuating irradiance, with TChla being the major absorbing pigment at 440 nm and photosynthetic carotenoids (PSC) at 490 nm. Absorption by chlorophyll c and photoprotective carotenoids (PPC) was much lower. Populations where cyanobacteria were prevalent were characterized by high PPC absorption, particularly at 490 nm, throughout most of the euphotic zone. The data suggested that the effect of pigments on the variability of phytoplankton absorption was due primarily to the variations in absorption by PPC. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 49 KW - PHYTOPLANKTON KW - PIGMENTS KW - ABSORPTION KW - ATLANTIC OCEAN SN - 0967-0637 TI - Phytoplankton pigment and absorption characteristics along meridional transects in the Atlantic Ocean SP - 637 AV - none EP - 660 ER - TY - JOUR ID - soton479569 UR - https://eprints.soton.ac.uk/479569/ IS - 2 A1 - Barrio Froján, Christopher R.S. A1 - MacIsaac, Kevin G. A1 - McMillan, Andrew K. A1 - Del Mar Sacau Cuadrado, María A1 - Large, Philip A. A1 - Kenny, Andrew J. A1 - Kenchington, Ellen A1 - De Cárdenas González, Enrique N2 -

The benthic macrofaunal community structure is investigated within and around a closed area at Sackville Spur in the Northwest Atlantic to ascertain whether continued exclusion of bottom fishing can be justified. This and other similar closed areas have been introduced by the Northwest Atlantic Fisheries Organisation (NAFO) to protect areas of likely occurrence of taxa that are indicative of vulnerable marine ecosystems (VMEs) from the damaging effects of bottom-contact fishing gear. Results reveal subtle yet significant differences in macrofaunal assemblage composition and community structure between inside and outside the closed area, between above and below the 1200-m depth contour (i.e. the historical depth limit of fishing), and between areas where dense sponge spicule mats are either present or absent. Differences were observed in many assemblage metrics; however, the most revealing was the greater abundance, biomass, diversity, and number of VME indicative taxa inside the closed area than outside. Overall community composition is also significantly different between treatments. Depth, sediment temperature, and the proportion of clay within sediments are important in shaping the faunal assemblage. The importance of the effects of fishing is discussed, although it is not possible to ascertain if fishing is the direct cause behind observed differences in the macrofaunal assemblage. A continued closure of the area is recommended, as well as options for streamlining the evaluation process of other closed areas.

VL - 69 TI - An evaluation of benthic community structure in and around the Sackville Spur closed area (Northwest Atlantic) in relation to the protection of vulnerable marine ecosystems AV - none EP - 222 N1 - Funding Information: The present investigation was undertaken as part of the NAFO Potential Vulnerable Marine Ecosystems?Impacts of Deep-sea Fisheries project (NEREIDA). The project is supported by Spain?s General Secretary of the Sea (SGM), Spain?s Ministry for the Rural and Marine Environment, the Spanish Institute of Oceanography, the Geological Survey of Canada, the Canadian Hydrographic Service, the Ecosystem Research Division of Fisheries and Ocean Canada, the UK?s Centre for the Environment Fisheries and Aquaculture Science (Cefas), the Russian Polar Research Institute of Marine Fisheries and Oceanography, and the Russian P.P. Shirshov Institute of Oceanology (RAS). The authors would like to acknowledge the hard work of the crew and scientists aboard the research vessel ?Miguel Oliver? who collected the samples for this study, as well as staff at the Bedford Institute of Oceanography (Canada) for their assistance in generating the data. Y1 - 2012/01/01/ JF - ICES Journal of Marine Science KW - Fishing exclusion zone KW - NAFO KW - Northwest Atlantic KW - Sackville Spur KW - Vulnerable marine ecosystem (VME) SN - 1054-3139 SP - 213 ER - TY - JOUR ID - soton425353 UR - https://eprints.soton.ac.uk/425353/ A1 - Barry, James A1 - Coghlan, Brian A1 - Cullagh, Alan A1 - Kerr, James R. A1 - King, James J. Y1 - 2018/09/27/ N2 -

Man-made barriers have led to river fragmentation, restricting fish migrations to critical habitat. Fragmentation is relevant to the Water Framework and Habitats (Annex II fish) Directives of the European Union. SNIFFER (Water Framework Directive 111) is a United Kingdom-developed fish passability assessment method with passability scores based on published data describing the physiological abilities of different fish species/life stages. SNIFFER is an objective protocol, but final scores require assessor opinion on specific nonquantified elements. The French ICE fish passability assessment protocol covers a larger number of fish species/life stages and removes the requirement for velocity readings (except in a few situations) and expert opinion with assessors following a decision tree process. In most situations, fewer direct measurements are required for the ICE protocol, and the evaluation process is quicker and simpler. Both protocols utilize a similar passability scoring system (0 = total barrier, 0.3 = high impact, 0.6 = low impact, 1 = no risk). Comparison of outcomes for species categories for both protocols was made in paired comparisons for 112 transversal sections (fish passage routes) recorded at 52 barriers (in-river structures) of varying complexity in Irish rivers. Overall scores were found to be in high agreement for species groups at impassable (Score 0) and no risk (Score 1) barriers. Protocol agreement dropped significantly for high-impact (Score 0.3) and low-impact (Score 0.6) barriers. Results are discussed in the context of barrier passability at the 52 structures examined, primarily in the context of Atlantic salmon (Salmo salar L.) and of sea lamprey (Petromyzon marinus L.). In total, 22 of the structures had one or more fishways or fish passage solutions built into them as part of the original design. Both protocols identified substantial problems for sea lamprey and adult salmon at the majority of the fish passage solutions surveyed. The merits and shortcomings of both protocols, for managers assessing fish passability at complex riverine structures, are discussed.

JF - River Research and Applications KW - Atlantic salmon KW - hydromorphology KW - river connectivity KW - sea lamprey SN - 1535-1459 TI - Comparison of coarse-resolution rapid methods for assessing fish passage at riverine barriers: ICE and SNIFFER protocols AV - public ER - TY - JOUR ID - soton444434 UR - https://eprints.soton.ac.uk/444434/ A1 - Bassoi, M. A1 - Shepherd, J.g. A1 - Secchi, E.r. A1 - Moreno, I.b. A1 - Danilewicz, D. Y1 - 2020/10/01/ N2 - The franciscana (Pontoporia blainvillei) is a coastal dolphin endemic to the south-western Atlantic Ocean. Incidental captures in fishing gillnets are the greatest conservation concern for this species. The present study examines the biophysical interactions between the franciscana prey composition and the marine environment. The feeding regime of franciscana was investigated from stomach contents of incidentally caught animals along the southern Brazilian coast. The characteristics of the franciscana habitat may reveal potential factors affecting the distribution and abundance of marine species, thus the franciscana prey (species number and size) was treated as a function of the oceanographic variables (sea surface temperature and chlorophyll-a), and the spatial (latitude and water depth), and temporal (season) parameters, through Linear and Generalized Linear Models (LM and GLM). Season and latitude were important predictors of the franciscana diet, followed by water temperature and depth. Chla parameter only influenced one fish species and therefore was not useful as an explanatory variable for our study. The influence of the predictors and prey distribution of the franciscana diet are similar to that found in the habitat by research cruise data. Some structures analysed (e.g. squid beaks) may remain longer in the stomachs. Therefore, the findings not only suggest a fairly opportunistic behaviour but it is likely that franciscana may occupy, and possibly for long periods, small spatial ranges. This behaviour might be a strategy for minimizing energetic costs by restricting movements to short distance areas, which can be an important factor for conservation planning along the southern Brazilian coast. JF - Continental Shelf Research VL - 201 KW - Cetacean KW - Environmental processes KW - Feeding ecology KW - Franciscana dolphin KW - GLM KW - Southwestern Atlantic ocean SN - 0278-4343 TI - Oceanographic processes driving the feeding ecology of franciscana dolphin off Southern Brazilian coast AV - none ER - TY - JOUR ID - soton357435 UR - https://eprints.soton.ac.uk/357435/ IS - C9 A1 - Bates, Nicholas R. Y1 - 2007/09// N2 - Between 1983 and 2005, continuous oceanic CO2 observations at two time series sites in the North Atlantic Ocean near Bermuda indicate that surface seawater dissolved inorganic carbon (DIC) and pCO2 increased annually at rates similar to that expected from oceanic equilibration with increasing CO2 in the atmosphere. In addition, seawater pH, CO32? ion concentrations, and CaCO3 saturation states have also decreased over time. There was considerable seasonal asymmetry in the oceanic CO2 sink or source rates, with wintertime air-to-sea CO2 influx greater than the summertime sea-to-air CO2 efflux. On an annual basis, the region was an oceanic sink for CO2, with a mean net annual air-sea CO2 flux rate of ?815 ± 251 and ?1295 ± 294 mmol CO2 m?2 yr?1, respectively, estimated using different synoptic and data assimilation model wind speed data sets. Peak-to-peak variability of ?850?1950 mmol CO2 m?2 yr?1 represented an interannual variability of ?0.2?0.3 Pg C yr?1 in the oceanic CO2 sink scaled to the subtropical gyre of North Atlantic Ocean. The long-term trend over the 1983?2005 period was a slight increase in the oceanic CO2 sink, associated primarily with a gradual increase in wind speed over the same period. Interannual variability of summertime (June?September) and fall (October?December) air-sea CO2 flux rates were correlated to the North Atlantic Oscillation (NAO) and strongly influenced by wind events such as hurricanes. Wintertime (January?May) air-sea CO2 flux rates were poorly correlated with the NAO and Arctic Oscillation (AO), although gas exchange rates were ?11?40% higher during concurrent El Niño periods compared to La Niña periods. JF - Journal of Geophysical Research: Oceans VL - 112 KW - carbon dioxide KW - oceanic sink KW - North Atlantic SN - 2169-9275 TI - Interannual variability of the oceanic CO2sink in the subtropical gyre of the North Atlantic Ocean over the last 2 decades AV - none ER - TY - JOUR ID - soton358311 UR - https://eprints.soton.ac.uk/358311/ IS - 3-4 A1 - Bates, Nicholas R. A1 - Hansell, Dennis A. Y1 - 2004/01// N2 - A dichotomy exists between rates of nitrogen fixation directly measured by biological techniques, and rates inferred from the geochemical distributions of excess nitrate within the thermocline of the North Atlantic Ocean. Part of the dichotomy relates to the temporal and spatial uncoupling between the event (i.e., nitrogen fixation by diazotrophs) and signal (i.e., excess nitrate (DINxs) in the thermocline), as well as the interannual variability of both. Here, temporal variability of excess nitrate in the subtropical mode water (STMW) of the North Atlantic Ocean is evaluated for the 1988?2001 period. The excess nitrate signal has a maximum in this water mass, and it is by far the largest volumetric component of thermocline waters in the subtropical gyre. DINxs variability and excess nitrate production rates in the STMW layer were well correlated with the North Atlantic Oscillation (NAO). For example, DINxs values (?1.5?2.8 ?mol kg?1) and excess nitrate production rates (?3.7 Tg N year?1) were generally high during positive phases of the NAO (e.g., 1989?1994; 1997?2000) and coincident with periods of higher atmospheric mineral dust input to the ocean. When the NAO was in its negative phase and dust inputs lower (e.g., 1995?1996; 2001), DINxs values (?0?1.0 ?mol kg?1) and excess nitrate production rates were generally low (up to ?0.6 Tg N year?1). The NAO potentially influences DINxs variability by modulating the extent and magnitude of STMW formation, thereby changing the fate of accumulated DINxs during circulation of STMW in the subtropical gyre, and the variability of nitrogen fixers through changes in dust inputs to the subtropical gyre. JF - Marine Chemistry VL - 84 KW - Temporal variability KW - Excess nitrate KW - North Atlantic Ocean SN - 0304-4203 TI - Temporal variability of excess nitrate in the subtropical mode water of the North Atlantic Ocean SP - 225 AV - none EP - 241 ER - TY - JOUR ID - soton358350 UR - https://eprints.soton.ac.uk/358350/ IS - 1-2 A1 - Bates, Nicholas R. A1 - Hansell, Dennis A. Y1 - 1999/10// N2 - Surface hydrographic and biogeochemical properties were measured contemporaneously at high spatial density during a transit from Chesapeake Bay, across the Middle Atlantic Bight [MAB] and Gulf Stream to the Sargasso Sea near Bermuda from 28 September?2 October 1996. Discrete samples were collected for total organic carbon [TOC], dissolved organic carbon [DOC], total organic nitrogen [TON], dissolved organic nitrogen [DON], total carbon dioxide [TCO2] and alkalinity [TA]. Continuous measurements of temperature, salinity, fluorescence, seawater pCO2 and atmospheric pCO2 were also collected. Estuarine waters of Chesapeake Bay (salinity>20) had high pCO2 (>600 ?atm) and high TOC (>200 ?M), DOC (>190 ?M) and TON (>20 ?M) concentrations reflecting the riverine input of terrestrial organic matter. Low seawater pCO2 concentrations (?350 ?atm), compared to MAB waters (?370?430 ?atm), were observed in the offshore plume of the Chesapeake. High TOC, TON, TCO2 and alkalinity concentrations were observed within a filament of low salinity shelf water abutting the western wall of the Gulf Stream. These filaments are apparently advected off the shelf near Cape Hatteras and subducted beneath the Gulf Stream. We estimate that this process will export shelf organic carbon into the North Atlantic basin at a rate ?3?31×1012 g C year?1, depending on the amount of water advected off the shelf. JF - Marine Chemistry VL - 67 KW - inorganic carbon KW - organic carbon KW - organic nitrogen KW - Middle Atlantic Bight KW - Gulf Stream KW - Sargasso Sea SN - 0304-4203 TI - A high resolution study of surface layer hydrographic and biogeochemical properties between Chesapeake Bay and Bermuda SP - 1 AV - none EP - 16 ER - TY - JOUR ID - soton1304 UR - https://eprints.soton.ac.uk/1304/ IS - 3 A1 - Bayon, G. A1 - German, C.R. A1 - Nesbitt, R.W. A1 - Bertrand, P. A1 - Schneider, R.R. Y1 - 2003/// N2 - Analysis of radiogenic isotopes in marine sediments can provide useful information on the provenance and transport of detrital material, directly relevant to paleoceanographic investigations. Here we show that the detrital Nd isotopic composition of recent SE Atlantic marine sediments matches the complex modern-day hydrography. In these same cores, glacial-interglacial isotopic variations are consistent with previous investigations (using different paleoceanographic proxies), which have shown that the relative influence of North Atlantic Deep Water (NADW) into the South Atlantic was reduced during glacial periods. In a novel departure, however, we also calculate the mass accumulation rates of terrigenous material delivered by each of Circumpolar Deep Water (CDW) and NADW to demonstrate that the accumulation of detritus delivered by CDW was enhanced significantly in the glacial South Atlantic. This enhanced transport flux could be explained by an increased flow of CDW into the glacial South Atlantic and/or an increased concentration of suspended terrigenous material transported by glacial CDW. JF - Geochemistry, Geophysics, Geosystems VL - 4 KW - Neodymium isotopes KW - detrital fractions KW - South Atlantic KW - deep water circulation KW - IMAGES. SN - 1525-2027 TI - Increased input of circumpolar deep water-borne detritus to the glacial SE Atlantic Ocean AV - none ER - TY - JOUR ID - soton360972 UR - https://eprints.soton.ac.uk/360972/ A1 - Bell, James B. A1 - Jones, Daniel O.B. A1 - Alt, Claudia H.S. Y1 - 2013/12/15/ N2 - The extent of megafaunal bioturbation was characterised at flat sedimented sites on the Mid-Atlantic Ridge (MAR) at 2500 m depth. This study investigated the properties of and spatial variation in surficial bioturbation at the MAR. Lebensspuren assemblages were assessed at four superstations either side of the MAR and in two different surface productivity regimes, north and south of the sub-polar front. High-definition ROV videos from these superstations were used to quantify area and abundance of 58 lebensspuren types. Lebensspuren area was lowest at the SW with 4.12% lebensspuren coverage and the SE & NW had the greatest area coverage of lebensspuren (9.69% for both). All stations except the SW were dominated by epifaunal, particularly track-style, lebensspuren. Infaunal mounds were more significant in the southern superstations, particularly in the SW. In terms of lebensspuren assemblage composition, all superstations were significantly different from one another, which directly corresponded with the composition of lebensspuren-forming epifauna. Lebensspuren assemblages appeared to have been primarily influenced by local-scale environmental variation and were independent of detrital flux. This investigation presented a novel relationship between lebensspuren and faunal density that conflicted with the traditionally held view of inverse proportionality and suggests that, at the MAR, megafaunal reworking was not the only significant control on lebensspuren assemblages. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 98 KW - Bioturbation KW - Megafaunal lebensspuren KW - Mid-Atlantic Ridge KW - Sub-Polar Front KW - ECOMAR SN - 0967-0645 TI - Lebensspuren of the Bathyal Mid-Atlantic Ridge SP - 341 AV - public EP - 351 ER - TY - JOUR ID - soton49656 UR - http://www.springerlink.com/content/l6298536p7u8v207/?p=717fb19827ec48debba3c73df928accb&pi=3 IS - 3 A1 - Bell, T.G. A1 - Malin, G. A1 - Kim, Y-N. A1 - Steinke, M. Y1 - 2007/09// N2 - In vitro DMSP-lyase activity (DLA) measurements were made during an Atlantic Meridional Transect (AMT) cruise in May 2004, which travelled through the southern and northern oligotrophic gyres. Along the transect, twice-daily measurements were taken from the surface (0.5 ? 8.0 m) and the chlorophyll maximum (chl max; 47 ? 150 m). Surface samples showed a large variation in DLA (0 ? 58.6 nmol L?1 h?1), while values for the chl max were lower and less variable (0 ? 8.7 nmol L?1 h?1). A negative correlation was observed between DLA:TChl a and primary production (carbon fixation rate) in surface samples (Spearman?s ? = ?0.57, p < 0.05, n = 17). Nitracline depth and the ratio of photo-protective to photosynthetic accessory pigments indicate that, as expected, surface phytoplankton communities in the gyres experience low nutrient concentrations and high light levels in comparison to communities from the chl max. Comparing pre-dawn and late-morning surface DLA values provides a pseudo time-series for each day and, in areas with elevated DLA, values for the late-morning samples were consistently higher than those taken at pre-dawn. Our field data set covers a geographically extensive area and includes the first DLA analyses from the oligotrophic South Atlantic gyre. JF - Aquatic Sciences VL - 69 KW - DMSP-lyase activity KW - DMSP KW - DMS KW - Oxidative Stress KW - Oligotrophic KW - Atlantic Meridional Transect SN - 1015-1621 TI - Spatial variability in DMSP-lyase activity along an Atlantic meridional transect SP - 320 AV - none EP - 329 ER - TY - JOUR ID - soton435414 UR - https://eprints.soton.ac.uk/435414/ A1 - Benoist, Noëlie M.A. A1 - Bett, Brian J. A1 - Morris, Kirsty J. A1 - Ruhl, Henry A. Y1 - 2019/11// N2 -

Biomass is a key variable for understanding the stocks and flows of carbon and energy in the environment. The quantification of megabenthos biomass (body size ? 1 cm) has been limited by their relatively low abundance and the difficulties associated with quantitative sampling. Developments in robotic technology, particularly autonomous underwater vehicles, offer an enhanced opportunity for the quantitative photographic assessment of the megabenthos. Photographic estimation of biomass has typically been undertaken using taxon-specific length-weight relationships (LWRs) derived from physical specimens. This is problematic where little or no physical sampling has occurred and/or where key taxa are not easily sampled. We present a generalised volumetric method (GVM) for the estimation of biovolume as a predictor of biomass. We validated the method using fresh trawl-caught specimens from the Porcupine Abyssal Plain Sustained Observatory (northeast Atlantic), and we demonstrated that the GVM has a higher predictive capability and a lower standard error of estimation than the LWR method. GVM and LWR approaches were tested in parallel on a photographic survey in the Celtic Sea. Among the 75% of taxa for which LWR estimation was possible, highly comparable biomass values and distribution patterns were determined by both methods. The biovolume of the remaining 25% of taxa increased the total estimated standing stock by a factor of 1.6. Additionally, we tested inter-operator variability in the application of the GVM, and we detected no statistically significant bias. We recommend the use of the GVM where LWRs are not available, and more generally given its improved predictive capability and its independence from the taxonomic, temporal, and spatial, dependencies known to impact LWRs.

JF - Progress in Oceanography VL - 178 KW - Benthos KW - Biovolume KW - Body size KW - Celtic Sea KW - Ecology KW - Image analysis KW - Northeast Atlantic KW - Photography KW - Porcupine Abyssal Plain SN - 0079-6611 TI - A generalised volumetric method to estimate the biomass of photographically surveyed benthic megafauna AV - public ER - TY - JOUR ID - soton469012 UR - https://eprints.soton.ac.uk/469012/ IS - 5 A1 - Bester, Marthán N. A1 - Reisinger, R. R. Y1 - 2010/05// N2 -

The Antarctic fur seal Arctocephalus gazella at Gough Island (40°20?S, 09°54?W) in the South Atlantic Ocean, first seen in October/November 2005, was recorded again in September-October 2009. Up to three different individual Antarctic fur seals were sighted on a single day, on a particular beach. A total of seven different individuals were recorded over a 3-week period, well before the onset of the breeding (pupping) season of the resident population of Subantarctic fur seals A. tropicalis. Positively identified individuals were all male, mostly subadult and lean. Only a fraction (~20%) of the available beaches was searched, and it is unknown if the Antarctic fur seals were still present at Gough Island during the austral summer breeding season of southern fur seals.

JF - Polar Biology VL - 33 KW - Antarctic fur seals KW - Gough Island KW - South Atlantic Ocean KW - Subantarctic fur seals SN - 0722-4060 TI - Vagrant Antarctic fur seals at Gough Island in 2009 SP - 709 AV - none EP - 711 ER - TY - RPRT N1 - Abstract deposited at the request of B.J.Bett. Any request to view the whole document should be directed to him - contact details included in abstract. ID - soton48593 UR - https://eprints.soton.ac.uk/48593/ A1 - Bett, B.J. Y1 - 2007/10/02/ N2 - This report is based on initial (at sea) observations of the seabed environment and fauna of Angola Blocks 18 and 31 as assessed during the MV Ocean Endeavour environmental survey (13 Oct-06 Nov, 2005). The report draws on the appearance and other physical characteristics of core samples and on photographic observations of the seafloor from deployments of the NOCS WASP system and the BP ROBIO lander. The megabenthos and fish populations appear to be consistent with a quiescent, fine-sedimented, bathyal region. No living cold seep (or comparable) communities were encountered during the survey. However, site ME1 (Block 31, large pockmark) has cemented sediments, both within the sediment column and at the sediment surface, and the fragmented shell remains of what appear to be large cold seep mussels; an extant community may be present in this vicinity. Other bivalve molluscs (both living and dead) of possible chemosynthetic nature were recovered from other sites (Block 31, on the periphery of diapiric features).

Should you wish to consult or cite this report please contact the author directly (Brian Bett, bjb@noc.soton.ac.uk, +44 (0)23 80596355).
PB - National Oceanography Centre T3 - 28 KW - Angola KW - Angolan Margin KW - Baited time-lapse camera KW - Bathyal KW - Benthic communities KW - BP KW - Chemosynthetic communities KW - Continental slope KW - Megacorer KW - Photography KW - Pockmarks KW - ROBIO lander KW - Salt diapirs KW - SE Atlantic KW - Seabed KW - Sediments KW - Videotape recording KW - WASP M1 - project_report TI - Interim report on the seabed environmental survey of Angola Blocks 18 and 31 (MV Ocean Endeavour cruise 2005) AV - none EP - 14 ER - TY - RPRT N1 - Abstract deposited at the request of B.J.Bett. Any request to view the whole document should be directed to him - contact details included in abstract. ID - soton48581 UR - https://eprints.soton.ac.uk/48581/ A1 - Bett, B.J. Y1 - 2007/10/01/ N2 - This cruise was carried out on behalf of BP Angola and comprised a seabed environmental
survey of Angola Blocks 18 and 31 (bathyal SE Atlantic). Seabed sampling was undertaken by
Megacorer to provide samples for macrobenthos, hydrocarbon, heavy metal and particle size
analysis. Seabed photography (still and video) was undertaken with the NOC WASP vehicle.
Baited, time-lapse camera deployments were undertaken using the BP ROBIO system
(Oceanlab, Aberdeen). The survey spanned water depths of 1300-2050m over the Angolan
Margin and included studies in and around seabed pockmarks and salt diapirs. Some
indications of fluid flow and chemosynthetic communities were encountered.

Should you wish to consult or cite this report please contact the author directly (Brian Bett,
bjb@noc.soton.ac.uk, +44 (0)23 80596355). PB - National Oceanography Centre T3 - 27 KW - Amphipods KW - Angola KW - Angolan Margin KW - baited-camera KW - bathyal KW - benthos KW - BP KW - chemosynthetic communities KW - continental slope KW - cruise 2005 KW - heavy metals KW - hydrocarbons KW - macrobenthos KW - Megacorer KW - Ocean Endeavour KW - particle size KW - photography KW - pockmarks KW - ROBIO KW - salt diapirs KW - SE Atlantic KW - seabed KW - sediments KW - videotape recording KW - WASP M1 - project_report TI - MV Ocean Endeavour cruise 13 Oct-06 Nov 2005. Seabed environmental survey of Angola Blocks 18 and 31 AV - none EP - 56 ER - TY - RPRT ID - soton48424 UR - https://eprints.soton.ac.uk/48424/ A1 - Bett, B.J. Y1 - 2007/09// N2 - This cruise formed part of the continuing Atlantic Margin Environmental Survey (AMES).
The objectives of the cruise were: 1) to continue the AMES process in the deep waters to the
north and west of Scotland on behalf of the Department of Trade and Industry (DTI); 2) to
carry out a seabed sampling programme in the Fladen Ground area of the North Sea on behalf
of the DTI; and 3) to conduct commercially funded seabed surveys in areas adjacent to those
addressed in objectives 1 and 2.
The cruise encompassed a number of survey areas: Ymir Ridge, Wyville Thomson Ridge
(including Darwin Mounds area), Faroe Bank Channel, Faroe-Shetland Channel (axial
transect), West Shetland Slope (bathymetric transect), West Shetland Slope (contourite body),
Enterprise survey (northwest of Shetland), Texaco survey (deep Faroe-Shetland Channel),
North of Shetland slope (Tranches 65-67), Statoil / BP survey (North of Shetland slope),
Marathon survey (Brae oil field, central North Sea), and the Fladen Ground (central North
Sea). In each of these areas seabed samples were obtained (Day grab, box core, Megacore,
gravity corer) to study various environmental parameters (hydrocarbons, heavy metals,
particle size) and macrobenthos communities. In the deep-water survey areas photographic
and video observations (SOC WASP system) of the seabed and its fauna were also
undertaken. PB - National Oceanography Centre T3 - 20 KW - AMES KW - Atlantic Margin Environmental Survey KW - benthic communities KW - barchans KW - box core KW - Charles Darwin KW - continental slope KW - contourites KW - coral KW - cruise 123C3-4 2000 KW - Darwin Mounds KW - Day grab KW - Faroe Bank Channel KW - Faroe Plateau KW - Faroe-Shetland Channel KW - Fladen Ground KW - gravity core KW - heavy metals KW - hydrocarbons KW - Lophelia pertusa KW - macrobenthos KW - megacorer KW - NE Atlantic KW - North of Shetland KW - North Sea KW - particle size KW - photography KW - Rockall Trough KW - seabed KW - sediments KW - videotape recording KW - WASP KW - West of Shetland KW - Wyville Thomson Ridge KW - Ymir Ridge M1 - project_report TI - RRS Charles Darwin Cruise 123C3-4, 19 Jul - 15 Sep 2000. Atlantic Margin Environmental Surveys and North Sea Environmental Surveys AV - public EP - 221 ER - TY - RPRT ID - soton48425 UR - https://eprints.soton.ac.uk/48425/ A1 - Bett, B.J. Y1 - 2007/09// N2 - This cruise formed part of the continuing Atlantic Margin Environmental Survey (AMES). The
general objective of this cruise was to carry out a seabed environmental survey of the deep
waters to the North of Shetland within the UKCS (United Kingdom Continental Shelf) area. The
cruise carried out seabed sampling and photography:

(a) To describe and characterise the ?iceberg ploughmark zone? on the North Shetland Slope.

(b) To assess alongslope variation in sediments and associated fauna on the North Shetland
Slope.

(c) To examine the potential contourite deposit and its associated fauna at the foot of the North
Shetland Slope.

(d) To investigate the seabed environment and fauna of the ?Pilot Whale Diapirs?.

(e) To describe and characterize ?hard ground? areas of the NE Faroe Plateau.

(f) To investigate the Tampen Slide area in the extreme north of the UKCS.

In each of these areas seabed samples were obtained (Day grab, box corer, Megacorer, gravity
corer) to study various environmental parameters (hydrocarbons, heavy metals, particle size)
and macrobenthos communities. Photographic and video observations (SOC WASP system) of
the seabed and its fauna were also undertaken. PB - National Oceanography Centre T3 - 21 KW - AMES KW - Atlantic Margin Environmental Survey KW - benthos KW - box cores KW - Charles Darwin KW - continental slope KW - contourites KW - cruise 2002 leg 2 KW - Day grab KW - Faroe Plateau KW - gravity cores KW - heavy metals KW - hydrocarbons KW - Kommandor Jack KW - macrobenthos KW - Megacorer KW - NE Atlantic KW - North Shetland Slope KW - ocean floor KW - particle size KW - photography KW - Pilot Whale Diapirs KW - ploughmarks KW - sediments KW - Tampen Slide KW - videotape recordings KW - WASP M1 - project_report TI - SV Kommandor Jack cruise Leg 2, 26 Jul-21 Aug 2002. DTI ?Northern Triangle? Environmental Survey: seabed survey of the deep waters to the north of Shetland AV - public EP - 92 ER - TY - RPRT N1 - Abstract deposited at the request of B.J.Bett. Any request to view the whole document should be directed to him - contact details included in abstract. ID - soton48399 UR - https://eprints.soton.ac.uk/48399/ A1 - Bett, B.J. Y1 - 2007/// N2 - RRS Charles Darwin cruise 123C3-4 formed part of the Atlantic Margin Environmental Survey
(AMES) and also carried out commercially funded deep-water seabed surveys. This contribution details
those activities and comprises four sections:
Part A. Report of seagoing operations and seabed observations undertaken in Tranche 4 (West of
Shetland) on behalf of Enterprise. This report addresses a survey of the deep (1030-1275m) Faroe-
Shetland Channel (61°36´N 001°55´W) encompassing a range of habitats (open slope; lineated slope,
contourite band; basin floor). These habitats are readily distinguished in terms of their megabenthic
communities; example photographs of the seafloor and its associated fauna are provided.
Part B. Report of seagoing operations and seabed observations undertaken in Tranches 65-67 (North
of Shetland) on behalf of Statoil and BP. This report addresses a survey of the deep (900-1000m) slope
North of Shetland (62°20´N 000°10´E) in a region of silty sand contourite deposit. The megabenthic
communities are dominated by cerianthid anemones and stalked sponges and also notable for the
occurrence of ?giant? seapens (Umbellula sp.). An intriguing observation is made of two occurrences (at
separate sites some 7km apart) of fabric bags on the seafloor that appear to have attracted (scavenging)
gastropods and prompted the deposition of numerous egg masses. Example photographs of the seafloor
and its associated fauna are provided.
Part C. Report of seabed observations made in the vicinity of Texaco site TX1: observation of a
?tubeworm? patch. This report addresses a survey of the deep (1550m) Faroe-Shetland Channel floor
(61°55´N 003°00´W). The survey is notable for recording what appeared to be small (c. 20m across)
discrete patch of what appeared to be tubeworms (Siboglinidae). Example photographs of the seafloor
and its associated fauna are provided.
Part D. Assessment of Texaco site TX1 environmental data. This report addresses a survey of the deep
(1550m) Faroe-Shetland Channel floor (61°55´N 003°00´W) and provides an analysis of physicochemical
(hydrocarbons, heavy metals, sediments) and biological parameters (macrobenthos) at the
survey site compared with 35 other sites in the deep Faroe-Shetland Channel obtained during the
Atlantic Frontier Environmental Network surveys of 1996 and 1998.

Should you wish to consult or cite this report or any of its constituent parts please contact the author directly
(Brian Bett, bjb@noc.soton.ac.uk, +44 (0)23 80596355). PB - National Oceanography Centre T3 - 26 KW - AMES KW - Atlantic Margin Environmental Survey KW - benthos KW - box cores KW - BP KW - Charles Darwin KW - continental slope KW - contourites KW - cruise 123C3-4 2000 KW - Enterprise KW - Faroe-Shetland Channel KW - gastropods KW - gravity core KW - habitats KW - heavy metals KW - hydrocarbons KW - macrobenthos KW - megabenthos KW - megacorer KW - NE Atlantic KW - North of Shetland KW - particle size KW - photography KW - seabed sediments KW - Siboglinidae KW - Statoil KW - Texaco KW - tubeworms KW - Umbellula KW - videotape recordings KW - WASP KW - West of Shetland M1 - project_report TI - Collected reports of commercial deep-water surveys carried out north and west of Shetland during RRS Charles Darwin cruise 123C3-4 AV - none EP - 124 ER - TY - RPRT ID - soton14405 UR - https://eprints.soton.ac.uk/14405/ A1 - Bett, B.J. Y1 - 2004/// N2 - The general aim of the cruise is to undertake a range of physical, chemical and biological investigations on and around Seine and Sedlo Seamounts. Specific objectives for the cruise included: a) the recovery of two current meter moorings from Seine Seamount (originally deployed from FS Poseidon in March 2004); b) to make underway observations of upper water column currents and zooplankton migrations (using ADCPs and 10 kHz echosounder); c) to assess water column hydrography, primary production and biogeochemistry through deployments of a CTD and water bottle rosette; d) to assess the biochemistry and biogeochemistry of suspended particulate matter by the use of SAPS (stand alone pumping system); e) to investigate the taxonomy, ecology and biogeochemistry of zooplankton communities using a multiple opening and closing net system (MOCNESS); f) to make photographic (stills and video) observations of the seabed and its larger fauna (megabenthos) using the SOC SHRIMP system (Seabed High Resolution Imaging Platform); and g) to carry out a suite of seabed sampling (coring, dredging and trawling) to investigate the taxonomy, ecology and biogeochemistry of seabed communities. The latter objective was immediately precluded by the unavailability of either the coring or trawl winches for the duration of this cruise. Only limited SHRIMP operations and no MOCNESS operations were undertaken at Sedlo Seamount as a result of the failure of the electro-optical tow winch. All other cruise objectives were fully achieved. PB - Southampton Oceanography Centre, University of Southampton T3 - 52 KW - benthic communities KW - biochemistry KW - biogeochemistry KW - circulation KW - cruise 282 2003 KW - CTD observations KW - current meters KW - currents KW - Discovery KW - hydrodynamics KW - hydrography KW - megabenthos KW - MOCNESS KW - moorings KW - NE Atlantic KW - organic matter KW - primary production KW - SAPS KW - seabed KW - seamounts KW - Sedlo Seamount KW - Seine Seamount KW - SHRIMP KW - zooplankton M1 - project_report TI - RRS "Discovery" Cruise 282, 30 Jun - 01 Aug 2003. The environment and ecology of Seine and Sedlo Seamounts, NE Atlantic AV - public EP - 102 ER - TY - JOUR ID - soton8016 UR - https://eprints.soton.ac.uk/8016/ IS - 8/10 A1 - Bett, B.J. Y1 - 2001/// N2 - The recent expansion of the Oil and Gas Industry in to the deep waters of the UK Atlantic Frontier prompted the industry and its regulator to reappraise the needs and means of environmental monitoring. In concert, deep-sea academics, specialist contractors, the regulator and the Industry, through the Atlantic Frontier Environmental Network (AFEN), devised and implemented a large-scale environmental survey of the deep waters to the north and west of Scotland. The AFEN-funded survey was carried out during the summers of 1996 and 1998, and involved two steps; an initial sidescan sonar mapping of the survey areas, followed up with direct seabed investigations by coring and photography. This contribution deals with the latter step. Seabed samples were collected to assess sediment type, organic content, heavy metals, hydrocarbons and macrobenthos. Photographic and video observations were employed to provide both ?routine? seabed assessments and to investigate particular sidescan features of note. Although essentially intended as a ?baseline? environmental survey, anthropogenic impacts are already evident throughout the areas surveyed. Indications of the effects of deep-sea trawling were frequently encountered (seabed trawl marks and areas of disturbed sediments), being present in almost all of the areas studied and extending to water depths in excess of 1000 m. Evidence of localised contamination of the seabed by drilling muds was also detected, though background hydrocarbon contamination is predominantly of terrestrial origin or derived from shipping. The benthic ecology of the UK Atlantic Margin is dominated by the marked differences in the hydrography of the Faroe?Shetland Channel (FSC) and the Rockall Trough (RT). Comparatively warm North Atlantic Water is common to both areas; however, in the FSC, cold (subzero) waters occupy the deeper parts of the channel (>600 m). The extreme thermal gradient present on the West Shetland Slope has a substantial influence on the distribution and diversity of the macrobenthos. While there is continuous variation in the fauna with depth, warm and cold water faunas are nonetheless quite distinct. The boundary region, centred on 400 m water depth, may be best characterised as an ecotone, having a mixed warm and cold water fauna with a distinctly enhanced diversity. The Wyville?Thomson Ridge largely prevents the cold waters of the deep FSC from entering the RT (they certainly do not influence the areas of the Malin/Hebrides Slope assessed during the survey). Consequently, the deep-water faunas north and south of the ridge are highly distinct. There is also a very marked difference in the diversity of the two faunas: diversity declines with depth in the FSC but increases with depth in the RT. The distribution of macrobenthos in the RT is largely continuous with depth, with little indication of local variations but some evidence of enhanced rates of change at around 1200 m, possibly associated with the presence of Labrador Sea Water. Other observations made during the course of the survey include: (a) the occurrence of sponge dominated communities (?ostebund?) at mid-slope depths (ca. 500 m) north and west of Shetland; (b) the discovery of a population of sediment surface dwelling enteropneusts associated with a sandy contourite deposit at the base of the West Shetland Slope (ca. 900 m); (c) the widespread and abundant occurrence of phytodetritus in the RT but not the FSC; and (d) the discovery of the ?Darwin Mounds? at ca. 1000 m in the northern RT, a field of numerous, small seabed mounds that support significant growths of the coral Lophelia pertusa. These mounds also have ?acoustically visible tails? with dense populations of xenophyophores (Syringammina fragilissima), a species found to be common elsewhere in the RT. JF - Continental Shelf Research VL - 21 KW - ATLANTIC MARGIN KW - MARINE ECOLOGY KW - BATHYAL ZONE KW - AFEN KW - BENTHIC COMMUNITIES KW - BIOLOGY SN - 0278-4343 TI - UK Atlantic margin environmental survey: introduction and overview of bathyal benthic ecology SP - 917 AV - none EP - 956 ER - TY - RPRT ID - soton298 UR - https://eprints.soton.ac.uk/298/ A1 - Bett, B.J. Y1 - 1999/// N2 - This cruise formed part of the Atlantic Margin Environmental Survey (AMES) 1998. The primary objective of the cruise was to carry out a large-scale seabed sampling survey of six areas of continental slope variously located north and west of Shetland and west of the Hebrides. In total over 100 seabed stations were sampled using either megacorer, box corer or Day grab, generating samples for the subsequent analysis of macrobenthos, hydrocarbons, heavy metals, particle size, total organic carbon and nitrogen and geology. Additional survey operations included photographic observation of the seafloor using still and video cameras mounted on the SOC WASP and epibenthic sledge vehicles and limited sampling with a gravity corer (British Geological Survey). The cruise also re-sampled (primarily for macrobenthos) a bathymetric transect of stations to the west of Shetland previously established during RRS Charles Darwin Cruise 112 C leg 2 (AMES 1996). Shipboard observations of seabed samples and video footage collected in the various survey areas are summarised in the report. Other general observations include (a) the effects of deep-sea trawling, observed to the west of Shetland and the Hebrides; (b) the widespread and mass occurrence of phytodetritus in the deeper waters of the Rockall Trough; (c) numerous observations of, frequently dense, populations of xenophyophores (Syringammina fragilissima) at around 1000 m depth in the Rockall Trough; and (d) the discovery of a field of coral (Lophelia pertusa) topped seabed mounds in the Rockall Trough immediately to the south of the Wyville-Thomson Ridge.

PB - Southampton Oceanography Centre, University of Southampton T3 - 25 KW - AMES KW - Atlantic Margin Environmental Survey KW - benthic communities KW - box corer KW - Charles Darwin KW - continental slope KW - coral KW - cruise 112C 1998 KW - CTD KW - day grab KW - deepwater trawling KW - Faeroe-Shetland Channel KW - gravity corer KW - Hebrides KW - heavy metals KW - hydrocarbons KW - Lophelia Pertusa KW - macrobenthos KW - megacorer KW - NE Atlantic KW - nitrogen KW - photography KW - photosledge KW - phytodetritus KW - pock marks KW - Rockall Trough KW - seabed mounds KW - sediments KW - Shetland Waters KW - Syringammina Fragilissima KW - TOC KW - total orgranic carbon KW - videotape recording KW - WASP KW - West of Shetland KW - xenophyophores M1 - project_report TI - RRS Charles Darwin Cruise 112C, 19 May-24 Jun 1998. Atlantic Margin Environmental Survey: seabed survey of deep-water areas (17th round Tranches) to the north and west of Scotland AV - public EP - 171 ER - TY - RPRT N1 - Temporary file loaded. Report awaiting rescanning. ID - soton17297 UR - https://eprints.soton.ac.uk/17297/ A1 - Bett, B.J. Y1 - 1998/// N2 - RRS Discovery Cruise 229 was the fourth in a series of cruises within a 3-year contract (MAS3 CT950018), BENGAL, funded under the MAST III programme of the EU, running from February 1996 to January 1999. The overall objective of the contract is to monitor the influence of the seasonal sedimentation of phytodetritus on the benthic biology and chemistry of a study site on the Porcupine Abyssal Plain.

Cruise 229 was timed to follow the expected deposition of phytodetritus on the seafloor in May/June. Although little phytodetritus was apparent, the cruise recovered a very comprehensive set of water column and seafloor samples. Successful operations included: multiple corer, box corer and Kasten core seabed sampling; CTD, rosette multi-sampler, marine snow profiler, stand-alone-pumping system and bottom water sampler studies of the water column; WASP seabed photography; semi-balloon otter trawl, chalut á perche (beam trawl) and epibenthic sledge megabenthos sampling; recovery and redeployment of long-term sediment trap, Bathysnap and Module Autonome de Colonisation moorings; and short-term operations of other landers and moorings, NIOZ benthic lander, BIOFEED enrichment experiment rig, DEMAR benthic amphipod trap and a moored stand-alone-pumping system. PB - University of Southampton T3 - 15 KW - ATLNE KW - bengal KW - benthic communities KW - bioturbation KW - coring KW - cruise 229 1997 KW - current meters KW - detritus KW - discovery KW - lander KW - microbiology KW - northeast atlantic KW - photography KW - respirometry KW - sediment chemistry KW - sediment traps KW - trawling KW - water sampling M1 - project_report TI - RRS "Discovery" Cruise 229, 02 Jul - 31 Jul 1997. BENGAL: high resolution and spatial study of the BENthic biology and Geochemistry of a north-eastern Atlantic abyssal Locality AV - public EP - 69 ER - TY - RPRT ID - soton314 UR - https://eprints.soton.ac.uk/314/ A1 - Bett, B.J. Y1 - 1997/// N2 - This was the second of two cruises, the overall objective of which was to undertake an integrated baseline environmental survey of the continental slope west of Shetland. The primary objective of this cruise was to carry out a large-scale seabed sampling survey of the area to the west of Shetland. In total some 200 seabed stations were sampled using either a Megacorer, Box corer or Day grab, and samples collected for the subsequent analysis of macrobenthos, hydrocarbons, heavy metals, particle size and total organic carbon and nitrogen. Additional survey operations included photographic reconnaissance of the seafloor using the SOC WASP system and the collection of demersal fish using pop up fish traps. Shipboard observation of seabed samples suggests that the survey region is very heterogeneous in terms of both sediments (as observed by TOBI sidescan sonar during the preceding cruise) and benthos. Particular features of note include highly developed epifaunal communities on the numerous ice rafted rocks in the 300 - 600m depth range and an abundant population of, apparently, sediment surface dwelling enteropneusts on a sandy contourite sheet located in the mid to north reaches of the survey at depths of 800 - 1000m. PB - Southampton Oceanography Centre, University of Southampton T3 - 7 KW - Atlantic Margin Environmental Survey KW - benthic communities KW - box corer KW - Charles Darwin KW - cruise 101C leg 2 1996 KW - day grab KW - demersal fish KW - Faeroe-Shetland Channel KW - fish trap KW - heavy metals KW - hydrocarbons KW - macrobenthos KW - megacorer KW - NE Atlantic KW - photography KW - photosledge KW - sediments KW - Shetland KW - trawl KW - WASP KW - West Shetland Shelf M1 - project_report TI - RRS Charles Darwin Cruise 101C Leg 2, 14 Jul-20 Aug 1996. Atlantic Margin Environmental Survey: seabed survey of the shelf edge and slope west of Shetland AV - public EP - 127 ER - TY - RPRT ID - soton247 UR - https://eprints.soton.ac.uk/247/ A1 - Bett, B.J. A1 - Billett, D.S.M. A1 - Masson, D.G. A1 - Tyler, P.A. Y1 - 2001/// N2 - RRS Discovery Cruise 248 aimed to carry out a multidisciplinary study of the environment and ecology of deep-water coral ecosystems and associated seabed features in the northeast Atlantic. The study was primarily focused on the Darwin Mounds area, northern Rockall Trough (59° 49?N, 07° 22?W), but also examined a number of sites in the Porcupine Seabight area. The cruise was divided into two legs (Govan-Stornoway, 8 Jul-21 Jul 2000; Stornoway-Southampton, 22 Jul-10 Aug 2000). Leg 1 focused on the ecology of the Darwin Mounds area, with seabed photographic surveys (SOC SHRIMP system), coring (Box and Multiple cores) and trawling (Agassiz) forming the main activities. Leg 2 began with detailed geological investigations of the Darwin Mounds area, concentrating on piston coring and sidescan sonar surveys. Leg 2 concluded with combined ecological and geological studies of carbonate mound sites on the Porcupine Bank and in the Porcupine Seabight.
Observations in the Darwin Mounds area confirmed the common occurrence of deep-water corals on these Mounds. The mounds themselves do not appear to be carbonate formations but may be better characterised as sand volcanoes. Numerous xenophyophores were observed in association with the mounds; however, no live specimens were recovered in any of the samples collected. Sidescan sonar images and seabed photography both suggested that the Darwin Mounds area had been subject to considerable commercial trawling with resultant apparent damage to the deep-water coral ecosystems.
The various operations undertaken in the Porcupine Seabight area were also successful in imaging giant carbonate mounds and their associated coral communities with both sidescan sonar and seabed photography, and in recovering biological sample material from these areas. In common with the Darwin Mounds area, the observations made suggested that deep-water fishing impacts on coral ecosystems were also evident in this region. PB - Southampton Oceanography Centre, University of Southampton T3 - 36 KW - ACES KW - Agassiz trawl KW - ATLNE KW - bottom photography KW - box corer KW - BATHYSNAP KW - bathyal KW - bathysiphon KW - benthic communities KW - carbonate mounds KW - cruise 248 2000 KW - CTD observations KW - current meters KW - Darwin Mounds KW - deep-water corals KW - Discovery KW - dredge KW - ECOMOUND KW - fishing effects KW - foraminifera KW - gravity corer KW - In Situ Optical Recorder KW - Lophelia KW - macrobenthos KW - meiobenthos KW - megabenthos KW - mud volcanoes KW - multiple corer KW - Mini Profiler Vehicle KW - Northeast Atlantic KW - organic chemistry KW - piston corer KW - pockmarks KW - Porcupine Bank KW - Porcupine Seabight KW - Rockall Trough KW - sediments KW - SHRIMP KW - sidescan sonar KW - Stand Alone Pumping System KW - Syringammina KW - xenophyophores M1 - project_report TI - RRS Discovery Cruise 248, 07 Jul-10 Aug 2000. A multidisciplinary study of the environment and ecology of deep-water coral ecosystems and associated seabed facies and features (The Darwin Mounds, Porcupine Bank and Porcupine Seabight) AV - public EP - 108 ER - TY - RPRT N1 - Abstract deposited at the request of B.J.Bett. Any request to view the whole document should be directed to him - contact details included in abstract. ID - soton48603 UR - https://eprints.soton.ac.uk/48603/ A1 - Bett, B.J. A1 - Hughes, J.A. Y1 - 2007/10/02/ N2 - This report details the analysis and interpretation of seabed sample data carried out on behalf of BP
Angola for an environmental survey of Angola Blocks 18 and 31 (bathyal SE Atlantic). Seabed
sampling was undertaken with the NOC Megacorer to produce material for the assessment of
hydrocarbons, heavy metals, particle size, total organic carbon and nitrogen and macrobenthos. Seabed
sampling spanned water depths of 1300-2050m over the Angolan Margin and included sites on the open
continental slope and on and around seabed pockmarks and salt diapirs. Analysis of the resultant data
indicates that many physical / chemical parameters vary systematically with water depth and with
seabed type (background, diapir and pockmark habitats). Contrary to expectation, sediments coarsen
and organic matter (total organic carbon and total nitrogen) increases with depth, this, however, may be
a local rather then regional trend. A number of the sampled diapir and pockmark sites are notable for
possible indicators of fluid flow, elevated total hydrocarbon levels, unusual hydrocarbon compositions
and variant macrobenthos species composition, all potentially indicative of fluid escape from the seabed
(? seep sites). The macrobenthos are highly diverse and likely include a majority of species new to
science. There is a strong trend of increasing biodiversity, particularly species richness, with depth and
some indication that biodiversity is enhanced at diapir sites and somewhat reduced at pockmark sites.
Controls on the species composition of the macrobenthos are undoubtedly complex and include both a
suite of depth varying factors together with local habitat variation, which likely includes the influence of fluid flow.

Should you wish to consult or cite this report please contact the author directly (Brian Bett, bjb@noc.soton.ac.uk, +44 (0)23 80596355). PB - National Oceanography Centre T3 - 30 KW - Angola KW - Angolan Margin KW - bathyal KW - benthos KW - biodiversity KW - BP KW - chemosynthetic communities KW - continental slope KW - fluid flow KW - heavy metals KW - hydrocarbons KW - macrobethos KW - Megacorer KW - pockmarks KW - salt diapirs KW - SE Atlantic KW - seabed KW - sediment particle size KW - sediments KW - species diversity KW - total nitrogen KW - Total Organic Carbon M1 - project_report TI - Seabed environmental survey of Angola Blocks 18WAD and 31: analysis of seabed samples AV - none EP - 58 ER - TY - RPRT ID - soton48096 UR - https://eprints.soton.ac.uk/48096/ A1 - Bett, B.J. A1 - Jacobs, C.J. Y1 - 2007/08// N2 - This cruise formed part of the continuing Atlantic Margin Environmental Survey (AMES). The objectives of the cruise were: a) to complete TOBI sidescan sonar survey of the ?White Zone?, begun on RRS Charles Darwin cruise 119C Leg A; b) to carry out photographic surveys of the ?White Zone? to ground truth the sidescan sonar imagery and provide an assessment of the seabed fauna; and c) to carry out seabed sampling to further ground truth the sidescan sonar imagery and generate samples for the future analysis of selected environmental parameters (hydrocarbons, elements, particle size). The cruise was undertaken in three phases: I) seabed photography and sampling of the southern ?White Zone? area (Wyville Thomson Ridge and adjacent areas of the Faroe Bank Channel and Faroe-Shetland Channel) surveyed by TOBI during RRS Charles Darwin cruise 119C Leg A; II) TOBI survey of the central Faroe-Shetland Channel, Faroe Slope and an area north of Shetland; and III) seabed photography and sampling of the areas surveyed by TOBI during phase two. The survey encountered a very wide

variety of seafloor environments, including areas of extremely dense gravel cover, areas of near complete cobble / rock / boulder cover, and a field of small barchan sand dunes on the floor (1,200m) of the Faroe Bank Channel. Two other notable TOBI features were also examined: 1. A new field of ?Darwin Mounds?, in the northern Rockall Trough, with associated colonies of the coral Lophelia pertusa and populations of the xenophyophore Syringammina fragilissima. 2. Localised areas of complex seabed topography (mud diapirs), in the area north of

Shetland. PB - National Oceanography Centre T3 - 19 KW - box corer KW - Charles Darwin KW - continental slope KW - coral KW - Cruise 119C Leg B 1999 KW - Darwin Mounds KW - Faroe Bank Channel KW - Faroe Plateau KW - Faroe-Shetland Channel KW - heavy metals KW - hydrocarbons KW - Lophelia pertusa KW - megacorer KW - NE Atlantic KW - North of Shetland KW - photography KW - Rockall Trough KW - seabed sediments KW - sidescan sonar KW - Syringammina Fragilissima KW - TOBI KW - videotape recording KW - WASP KW - West of Shetland KW - White Zone KW - Xenophyophores M1 - project_report TI - RRS Charles Darwin Cruise 119C Leg B, 13 Aug - 14 Sep 1999. White Zone (WhiZ) environmental survey: seabed survey of the deep waters to the north and west of Shetland AV - public EP - 120 ER - TY - JOUR ID - soton8021 UR - https://eprints.soton.ac.uk/8021/ IS - 1/4 A1 - Bett, B.J. A1 - Malzone, M.G. A1 - Narayanaswamy, B.E. A1 - Wigham, B.D. Y1 - 2001/// N2 - We report a ten-year study of the abundance and activity of megabenthos on the Porcupine Abyssal Plain, northeast Atlantic, together with observations on the occurrence of phytodetritus at the deep-sea floor (4850 m). Using the Southampton Oceanography Centre time-lapse camera system, ?Bathysnap?, we have recorded a radical change in the abundance and activity of megabenthos between the two periods of study (1991?1994 and 1997?2000). In 1991?1994, the larger megabenthos occurred at an abundance of c. 71.6/ha and were dominated by large holothurians. In addition, there were very substantial populations of smaller megabenthic ophiuroids (c. 4979/ha). Together, the total megabenthos are estimated to track over some 17 cm2/m2/d (exploiting 100% of the surface of the seabed in c. 2.5 years). In 1997?2000, the larger megabenthos increased to an abundance of c. 204/ha and were joined by exceptional numbers of a small holothurian species (Amperima rosea, 6457/ha) and ophiuroids (principally Ophiocten hastatum, 53,539/ha). The total megabenthos population was tracking at an estimnated rate of c. 247 cm2/m2/d (exploiting 100% of seabed in just 6 weeks). Coincident with these increases in the abundance and activity of the megabenthos, there were apparently no mass depositions of aggregated phytodetritus to the seabed in the summers of 1997?1999. Mass occurrences of phytodetritus had been noted during the summer months of the three years previously studied (1991, 1993 and 1994), with covering between 50 and 96% of the sediment surface. There is a statistically significant (p<0.02) negative correlation between maximum extent of this seabed cover of phytodetritus and seabed tracking by megabenthos. Additional studies [Lampitt et al., Progr. Ocean. 50 (2001)], indicate that there were no substantial changes in surface ocean primary productivity, in export flux, or in the composition of the flux that might otherwise account for the apparent absence of observable concentrations of phytodetritus during the summers of 1997?1999. We postulate that the marked increase in megabenthic tracking activity resulted in the removal (via consumption, disaggregation, burial etc.) of the bulk of the incoming phytodetrital flux during these years. A simple conceptual model, based on the apparent phytodetrital fluxes observed in 1991 and 1993, suggests that the megabenthos tracking rates estimated for 1997?1999 are sufficient to account for near-total removal of this flux. However, we are not able to estimate other processes removing phytodetritus (i.e. other elements of the benthos) that may also have increased between 1991?1994 and 1997?1999. Other independent studies [e.g. Ginger et al., Progr. Ocean. 50 (2001)] of flux constituents support the possibility that just a few species of megabenthos (e.g. A. rosea, and O. hastatum) could well have consumed a major proportion of the incoming flux and so substantially modified the composition of the organic matter available to other components of the benthos. JF - Progress in Oceanography VL - 50 KW - MEGABENTHOS KW - NORTHEAST ATLANTIC OCEAN KW - HOLOTHURIANS KW - TEMPORAL VARIABILITY KW - BIOLOGY SN - 0079-6611 TI - Temporal variability in phytodetritus and megabenthic activity at the seabed in the deep northeast Atlantic SP - 349 AV - none EP - 368 ER - TY - JOUR ID - soton362278 UR - https://eprints.soton.ac.uk/362278/ IS - 4 A1 - Bett, Brian J. A1 - Narayanaswamy, Bhavani E. Y1 - 2014/12// N2 - The deep-sea floor is increasingly subject to anthropogenic impacts. Consequently, there are increasing efforts to develop appropriate management strategies. Species-level indicators and assessments are hampered in the deep sea by the high proportion of unknown species routinely encountered. If environmental management is to keep pace with exploitation, alternative approaches including higher taxon surrogacy (taxonomic sufficiency) must be considered. Here we compare genus- and species-level studies of the diversity and ecology of deep-sea macrobenthos on the West Shetland Slope (NE Atlantic). This is an environmentally complex region that encompasses a biogeographic transition from temperate North Atlantic to Arctic conditions, and so may be particularly challenging for any general relationship between species- and genus-level analyses. We ask two questions: (i) does genus diversity reflect species diversity and (ii) does genus-level ecology reflect species-level ecology? We conclude that among the West Shetland Slope macrobenthos: (i) genus-level ?- and ?-diversity measures are highly correlated with and good predictors of their species-level equivalents and (ii) that their ecology is very well described by genus-level data. We further note that, given the complexity of the West Shetland Slope environment, it may be reasonable to expect these conclusions to hold in other deep-sea environments. JF - Marine Ecology VL - 35 KW - Biodiversity KW - deep sea KW - higher taxon surrogacy KW - macrobenthos KW - Northeast Atlantic KW - species-genus ratio KW - taxonomic sufficiency SN - 0173-9565 TI - Genera as proxies for species ?- and ?-diversity: tested across a deep-water Atlantic-Arctic boundary SP - 436 AV - none EP - 444 ER - TY - JOUR ID - soton477420 UR - https://eprints.soton.ac.uk/477420/ IS - 3 A1 - Bigg, Grant R. A1 - Marsh, Robert N2 - The life history and oceanic impact of three very large icebergs that escaped together from the Weddell Sea sea ice, near the tip of the Antarctic Peninsula, are traced from March 2014. Despite the initial proximity of these three icebergs, they followed very different trajectories across the South Atlantic until their eventual break-up and melting 1 year later. The largest, giant iceberg, B17a, spent extensive periods grounded near two different islands. The triplet's gradual melting is examined through the impact on the icebergs' dimensions, but also the meltwater's oceanic influence on the local salinity and primary productivity. It is found that there was generally a significant local surface and mixed-layer freshening of a few tenths of a practical salinity unit, up to several hundred kilometres away from the 10?20 km-sized icebergs. In contrast, the chlorophyll impact was highly temporally variable, although it tended to be larger in the summer. Break-up of these large icebergs did not occur until near the end of their life. We also show that modelling the trajectories of individual very large icebergs can be reasonable for up to 2 weeks if the characteristics of the iceberg and the local ocean and atmospheric forcing are well known.

VL - 35 TI - The history of a cluster of large icebergs on leaving the Weddell Sea pack ice and their impact on the ocean AV - public EP - 193 N1 - Funding Information: Aspects of the original monitoring and modelling of the triplet of icebergs were funded by the Natural Environmental Research Council through grant NE/M007820/1 ?Iceberg forecasting - from days to decades (ICECAST)?. Publisher Copyright: Copyright © The Author(s), 2023. Published by Cambridge University Press on behalf of Antarctic Science Ltd. Y1 - 2023/06/24/ JF - Antarctic Science KW - South Atlantic KW - divergence KW - iceberg-island interaction KW - icebergs KW - ocean fertilization KW - ocean salinity SN - 0954-1020 SP - 176 ER - TY - JOUR ID - soton8713 UR - https://eprints.soton.ac.uk/8713/ A1 - Billett, D. A1 - Bett, B. A1 - Gooday, A. Y1 - 2000/// JF - Deep-Sea Newsletter VL - No.29 KW - ACES KW - PROJECT KW - ATLANTIC CORAL ECOSYSTEM STUDY KW - ECOMOUND KW - GEOMOUND KW - EUROPEAN ATLANTIC MARGIN KW - DEEP WATER KW - CONTINENTAL SLOPE TI - Atlantic Coral Ecosystem Study (ACES) AV - none ER - TY - RPRT ID - soton43104 UR - https://eprints.soton.ac.uk/43104/ A1 - Billett, D.S.M. Y1 - 2006/// N2 - RRS Charles Darwin Cruise 179 was one of a series of cruises studying the biology, geology, biogeochemistry and physical oceanography of the Portuguese margin canyons. The cruise contributed to the European Union Framework Programme VI Integrated Project HERMES (Hotspot Ecosystem Research on the Margins of European Seas). Four key canyon areas on the European margin are being studied in HERMES: the Portuguese margin, the Irish margin and the Western and Eastern Mediterranean. On the Portuguese margin four canyons had been selected for multidisciplinary studies by the HERMES community: the Nazaré Canyon, Setúbal Canyon, Lisbon Canyon and the Cascais Canyon.

RRS Charles Darwin cruise 179 was divided into two legs (Cartagena to Lisbon, 14 April to 1 May 2006; Lisbon to Falmouth, 1 to 17 May 2006). Leg 1 focused on the upper and middle parts of the Setúbal and Lisbon canyons, which join together at a depth of about 2000m, and the upper and middle Cascais Canyon. Leg 2 sampled the lower Cascais and Setúbal canyons and a wide variety of depths in the Nazaré Canyon. The principal sampling activities were seabed photographic and video imaging (NOCS SHRIMP system), deep-tow 30 kHz sidescan sonar imaging (NOCS TOBI system), coring (Megacorer, Piston Corer and Box Corer), trawling (Agassiz Trawl), and benthic boundary layer particulate biogeochemistry using CTD-mounted Stand Alone Pump Systems (SAPS).

Seabed photo-transects at depths between 300 and 4500m confirmed that large parts of all the canyons were covered in a sediment drape, with little evidence of epifaunal megafauna within the canyon axis, but with localised communities of suspension feeding sponges, cnidarians (soft and stony corals), crinoids and asteroids on rocky ledges around the thalweg (central channel) of the canyons. Photo-transects across the thalwegs of the canyons revealed fascinating changes in the nature of the seabed (e.g. ripple patterns) and fauna (e.g. xenophyophores (giant protozoans) on the flanks of the Nazaré Canyon thalweg). New sidescan sonar images were obtained of the Lisbon and Cascais canyons and the base of the continental slope in the vicinity of the Cascais and Setúbal canyons. Coring and trawling focused on comparable sites at c. 3400m and 4400m in the lower canyons. Burrowing holothurians were evident in all three canyons at c. 3400m, but only in the Nazaré Canyon were they superabundant.

This was the penultimate scientific cruise of RRS Charles Darwin. The ship has given UK and European marine science many years of excellent service. She will be greatly missed, and will be succeeded by RRS James Cook in 2006. PB - National Oceanography Centre T3 - 13 KW - abyssal KW - Agassiz Trawl KW - asteroid KW - box corer KW - bathyal KW - benthic communities KW - canyons KW - Cascais Canyon KW - Charles Darwin KW - coral KW - crinoid KW - cruise 179 2006 KW - CTD observations KW - HERMES KW - Lisbon Canyon KW - macrobenthos KW - meiobenthos KW - megabenthos KW - Megacorer KW - molpadiid holothurian KW - Nazaré Canyon KW - Northeast Atlantic KW - piston corer KW - Portuguese margin KW - SAPS KW - seabed photography KW - sediments KW - Setúbal canyon KW - SHRIMP KW - sidescan sonar KW - Stand Alone Pump System KW - submarine canyons KW - thalweg KW - TOBI KW - xenophyophores M1 - project_report TI - RRS Charles Darwin Cruise 179, 14 Apr - 17 May 2006. Hotspot ecosystem research in the Setúbal, Lisbon, Cascais and Nazaré canyons on the Portuguese continental margin AV - public EP - 66 ER - TY - RPRT N1 - Smaller version of pdf added Sept 2005 as original is slow to open ID - soton292 UR - https://eprints.soton.ac.uk/292/ A1 - Billett, D.S.M. Y1 - 2000/// N2 - RRS Challenger Cruise 142 aimed to study 1) long-term change in abyssal benthic communities (4850m, Porcupine Abyssal Plain) and 2) coral communities on carbonate mounds (c. 800m, Porcupine Seabight).

Sampling on the first leg was focussed at a central locality 48°50?N, 16°30?W) on the Porcupine Abyssal Plain. This locality had been sampled on 9 separate cruises over a 9-year period (1989-1998). A radical change in the composition of the benthic fauna had occurred in recent years and this cruise aimed to follow further long-term change in the benthic fauna and sediment biogeochemistry. In addition, in order to set the results from this central locality in a basin-wide context, further sampling was undertaken across the Porcupine Abyssal Plain.

Sampling on the second leg concentrated on the giant carbonate mounds discovered in recent years on the eastern and northern flanks of the Porcupine Seabight. The mounds had well-developed coral communities. Samples and video of the coral were collected. Other seabed features also noted in sidescan sonar records on previous cruises were imaged as well. PB - Southampton Oceanography Centre, University of Southampton T3 - 30 KW - BENGAL KW - benthic communities KW - bottom photography KW - carbonate deposits KW - Challenger KW - coral KW - corers KW - cruise 142 1999 KW - dredge KW - epibenthic sledge KW - geochemistry KW - holothurians KW - landers KW - megafauna KW - microbiology KW - Northeast Atlantic KW - photosledge KW - Porcupine Abyssal Plain KW - Porcupine Seabight KW - time series KW - trawls KW - videotape M1 - project_report TI - RRS Challenger Cruise 142, 19 Apr-19 May 1999. Temporal and spatial variability of benthic communities on the Porcupine Abyssal Plain and in the Porcupine Seabight AV - public EP - 79 ER - TY - RPRT ID - soton303 UR - https://eprints.soton.ac.uk/303/ A1 - Billett, D.S.M. Y1 - 1998/// N2 - Challenger Cruise 135 was the fourth of a series of cruises funded by the European Commission?s Marine Science and Technology III (MAST III) Programme as part of the BENGAL project (MAS3 CT 950018). Sampling commenced in September 1996 to assess changes in benthic systems over a period of one and a half years at a single, abyssal locality in the NE Atlantic (48° 50?N, 16° 30?W). It is hoped that changes within a year (seasonal) and between years (inter-annual) will be detected.

Challenger Cruise 135 replaced a longer cruise planned for the vessel Atalante, which had to be cancelled as a result of a strike by the crew of that vessel. Challenger Cruise 135 was planned at extremely short notice with the aim of undertaking a reduced sampling programme and recovering vital moorings that had been in place on the seabed for periods of up to 1 year. Samples of the benthos and overlying water column were collected using a multiple corer, box corer, trawl and CTD. Two activities planned for the Atalante cruise, sampling of benthopelagic fauna using the University of Hamburg MOCNESS net system and photographing the seabed using the Southampton Oceanography Centre WASP system, could not be undertaken. PB - Southampton Oceanography Centre, University of Southampton T3 - 19 KW - abyssal plains KW - BENGAL KW - benthic communities KW - bioturbation KW - bottom photography KW - Challenger KW - coring KW - cruise 135 1997 KW - CTD KW - current meters KW - microbiology KW - MOCNESS KW - moorings KW - Northeast Atlantic KW - respirometry KW - sediment geochemistry KW - sediment traps KW - thermistor chain KW - trawling KW - WASP KW - water sampling M1 - project_report TI - RRS Challenger Cruise 135, 15 Oct-30 Oct 1997. BENGAL: High resolution temporal and spatial study of the BENthic biology and Geochemistry of a north-eastern Atlantic abyssal Locality AV - public EP - 49 ER - TY - JOUR ID - soton7917 UR - https://eprints.soton.ac.uk/7917/ IS - 1/4 A1 - Billett, D.S.M. A1 - Bett, B.J. A1 - Rice, A.L. A1 - Thurston, M.H. A1 - Galéron, J. A1 - Sibuet, M. A1 - Wolff, G.A. Y1 - 2001/// N2 - A radical change in the abundance of invertebrate megafauna on the Porcupine Abyssal Plain is reported over a period of 10 years (1989?1999). Actiniarians, annelids, pycnogonids, tunicates, ophiuroids and holothurians increased significantly in abundance. However, there was no significant change in wet weight biomass. Two holothurian species, Amperima rosea and Ellipinion molle, increased in abundance by more than two orders of magnitude. Samples from the Porcupine Abyssal Plain over a longer period (1977?1999) show that prior to 1996 these holothurian species were always a minor component of the megafauna. From 1996 to 1999 A. rosea was abundant over a wide area of the Porcupine Abyssal Plain indicating that the phenomenon was not a localised event. Several dominant holothurian species show a distinct trend in decreasing body size over the study period. The changes in megafauna abundance may be related to environmental forcing (food supply) rather than to localised stochastic population variations. Inter-annual variability and long-term trends in organic matter supply to the seabed may be responsible for the observed changes in abundance, species dominance and size distributions. JF - Progress in Oceanography VL - 50 KW - megabenthos KW - northeast atlantic ocean KW - sampling KW - holothurians KW - abundance KW - biology SN - 0079-6611 TI - Long-term change in the megabenthos of the Porcupine Abyssal Plain (NE Atlantic) SP - 325 AV - none EP - 348 ER - TY - JOUR ID - soton55517 UR - https://eprints.soton.ac.uk/55517/ IS - 8-10 A1 - Black, Kevin S. A1 - Fones, Gary R. A1 - Peppe, Oli C. A1 - Kennedy, Hilary A. A1 - Bentaleb, Ilhem Y1 - 2001/05// N2 - A new, multi-purpose autonomous benthic lander is described, and preliminary experimental data are presented relating to deployments in the Atlantic Frontier (eastern north Atlantic) during the recent UK Thematic Programme ?BENBO?. The autonomous lander was deployed at two contrasting sites ? Site A (mouth of Rockall Trough; 3570 m) and Site B (Hatton-Rockall Bank; 1100 m) ? before and following the spring-time surface ocean phytoplankton bloom (May & July, 1998, respectively). Diffusive oxygen uptake and nutrient flux data were obtained using two interchangeable modules ? a profiling oxygen micro-electrode unit and a benthic chamber unit. Diffusive O2 uptake across the sediment?water interface and the O2 penetration depths within the sediment were determined from the oxygen micro-profiles. The shallower site, which had previously received phyto-detrital input, had a comparatively large diffusive oxygen uptake within the sediment (1.2 mmol m?2 d?1) and a maximum penetration depth of only 21 mm. The deeper site had greater oxygen penetration depths (80 mm) but a lower diffusive oxygen uptake of 0.6 mmol m?2 d?1, indicative possibly of little or no phyto-detrital input. Visual observations of retrieved sediment cores support this conclusion, however Site A has also displays generally lower organic content and lower macrobenthic biomass which may contribute to this observation. Nutrient pore water profile data indicated fluxes of nitrate of 0.161 mmol m?2 d?1 and phosphate 0.0008 mmol m?2 d?1 into the overlying water. However, the benthic chamber studies showed virtually no change in nutrient concentrations, due probably to the relatively short deployment time used.

JF - Continental Shelf Research VL - 21 KW - Oxygen KW - Nutrients KW - Sediments KW - Benthic lander KW - North Atlantic KW - Fluxes SN - 0278-4343 TI - An autonomous benthic lander: preliminary observations from the UK BENBO thematic programme SP - 859 AV - none EP - 877 ER - TY - JOUR ID - soton428614 UR - https://eprints.soton.ac.uk/428614/ A1 - Blake-Mizen, Keziah A1 - Hatfield, Robert G. A1 - Stoner, Joseph S. A1 - Carlson, Anders E. A1 - Xuan, Chuang A1 - Walczak, Maureen A1 - Lawrence, Kira T. A1 - Channell, James E.T. A1 - Bailey, Ian Y1 - 2019/04/01/ N2 -

We present new sedimentological and environmental magnetic records spanning ?3.2?2.2 Ma, during the intensification of Northern Hemisphere glaciation, from North Atlantic Integrated Ocean Drilling Program Site U1307 on Eirik Drift. Our new datasets and their high-fidelity age control demonstrate that while inland glaciers ? and potentially also at times restricted iceberg-calving margins ? have likely existed on southern Greenland since at least ?3.2 Ma, persistent and extensive iceberg-calving glacial margins were only established in this region at 2.72 Ma, ?300 kyr later than in northeastern and eastern Greenland. Despite a dramatic increase in Greenland-sourced ice-rafted debris deposition on Eirik Drift at this time, contemporaneous changes in the bulk magnetic properties of Site U1307 sediments, and a reduction in sediment accumulation rates, suggest a decrease in the delivery of Greenland-sourced glaciofluvial silt to our study site. We attribute these changes to a shift in depositional regime from bottom-current-dominated to glacial-IRD-dominated between ?2.9 and 2.7 Ma, in response to a change in the depth of the flow path of the Western Boundary Undercurrent relative to our study site.

JF - Quaternary Science Reviews VL - 209 KW - Greenland Ice Sheet KW - Ice-rafted debris KW - North Atlantic KW - Northern Hemisphere glaciation KW - Paleoceanography KW - Paleoclimatology KW - Paleomagnetism KW - Plio-Pleistocene transition KW - Relative paleointensity SN - 0277-3791 TI - Southern Greenland glaciation and Western Boundary Undercurrent evolution recorded on Eirik Drift during the late Pliocene intensification of Northern Hemisphere glaciation SP - 40 AV - public EP - 51 ER - TY - JOUR N1 - Funding Information: The authors would like to gratefully acknowledge the editor, Dr Kristopher B. Karnauskas, and three anonymous reviewers for their critical reviews that helped to improve this manuscript. The authors would also like to acknowledge funding from the Natural Environment Research Council (NE/M003507/1 and NE/K010654/1) and the European Research Council (GA 638665). The WAVEWATCH III infragravity wave height models, used in this study, are from the work of Ardhuin et al.?(2014) and downloaded from http://ftp://ftp.ifremer.fr/ifremer/ww3/HINDCAST/GLOBAL_IG, last accessed on October, 2019. Publisher Copyright: © 2020. The Authors. ID - soton441196 UR - https://eprints.soton.ac.uk/441196/ IS - 6 A1 - Bogiatzis, P. A1 - Karamitrou, A. A1 - Ward Neale, J. A1 - Harmon, N. A1 - Rychert, C. A. A1 - Srokosz, M. Y1 - 2020/06/01/ N2 -

Infragravity waves are generated along coasts, and some small fraction of their energy escapes to the open oceans and propagates with little attenuation. Due to the scarcity of deep-ocean observations of these waves, the mechanism and the extent of the infragravity waves energy leakage from the coasts remains poorly understood. Understanding the generation and pathways of infragravity wave energy is important among others for understanding the breakup of ice-shelves and the contamination of high-resolution satellite radar altimetry measurements of sea level. We examine data from 37 differential pressure gauges of Ocean Bottom Seismometers (OBS) near the equatorial mid-Atlantic ridge, deployed during the Passive Imaging of the Lithosphere-Asthenosphere Boundary (PI-LAB) experiment. We use the beamforming technique to investigate the incoming directions of infragravity waves. Next, we develop a graph-theory-based global back-projection method of noise cross-correlation function envelopes, which minimizes the effects of array geometry using an adaptive weighting scheme. This approach allows us to locate the sources of the infragravity energy. We assess our observations by comparing to a global model of infragravity wave heights. Our results reveal strong coherent energy from sources and/or reflected phases at the west coast of Africa and some sources from South America. These energy sources are in good agreement with the global infragravity wave model. In addition, we also observe infragravity waves arriving from North America during specific events that mostly occur during October?February 2016. Finally, we find indications of waves that propagate with little attenuation, long distances through sea ice, reflecting off Antarctica.

JF - Journal of Geophysical Research: Oceans VL - 125 KW - Africa KW - Antarctica KW - Atlantic Ocean KW - back-projection KW - beamforming KW - infragravity waves SN - 2169-9275 TI - Source regions of infragravity waves recorded at the bottom of the equatorial Atlantic Ocean, using OBS of the PI?LAB experiment AV - public EP - 27 ER - TY - JOUR ID - soton413476 UR - https://eprints.soton.ac.uk/413476/ IS - 7 A1 - Bourne, A.J. A1 - Davies, S.M. A1 - Abbott, P.M. A1 - Rasmussen, S.O. A1 - Steffensen, J.P. A1 - Svensson, A. Y1 - 2013/10// N2 -

Nineteen new Icelandic tephra layers are identified in NGRIP and NEEM ice spanning Greenland Interstadial-9 (GI-9) and the early phase of GI-8 (?38 000-40 500 b2k). Fourteen tephras are identified in the NGRIP record and five direct correlatives are identified in NEEM, thus indicating the occurrence of 14 separate volcanic events. With two exceptions, the tephras are tholeiitic basalt in composition and despite having very similar geochemical signatures can, in most cases, be discriminated from one another using their TiO2 values. All of these tephra layers fall within the compositional range of the Faroe Marine Ash Zone III (FMAZ III) deposit previously identified in ocean cores from the Faroes region and previously correlated to NGRIP 2066.95m by Davies et al. (). Thus, the FMAZ III in the marine realm is most likely a complex ash zone that represents a series of closely timed Grimsvötn eruptions that, as yet, can only be stratigraphically separated in the high-resolution ice-core records. The geochemical signatures and stratigraphic positions of the new ice-core layers means that the FMAZ III tephra deposit, as currently defined in the marine realm, cannot be correlated to NGRIP 2066.95m or any other ice-core tephra horizons preserved during this interval.

JF - Journal of Quaternary Science VL - 28 KW - Faroe Marine Ash Zone III KW - Greenland KW - North Atlantic KW - Synchronisation KW - Tephra SN - 0267-8179 TI - Revisiting the Faroe Marine Ash Zone III in two Greenland ice cores: Implications for marine-ice correlations SP - 641 AV - none EP - 646 ER - TY - JOUR ID - soton12534 UR - https://eprints.soton.ac.uk/12534/ IS - 1-2 A1 - Bowie, A.R. A1 - Achterberg, E.P. A1 - Blain, S. A1 - Boyé, M. A1 - Croot, P.L. A1 - Laan, P. A1 - Sarthou, G. A1 - De Baar, H.J.W. A1 - Worsfold, P.J. Y1 - 2003/// N2 - A shipboard analytical intercomparison of dissolved (<0.2 m) iron in the surface waters of the Atlantic Ocean was undertaken during October 2000. A single underway surface (1?2 m) seawater sampling and filtration protocol was used, in order to minimise differences from possible sample contamination. Over 200 samples (1/h) were collected over 12 days and analysed immediately using four different analytical methods, based on three variants of flow injection with luminol chemiluminescence (FI?CL) and cathodic stripping voltammetry (CSV). Dissolved iron concentrations varied between 0.02 and 1.61 nM during the intercomparison. On average, CSV [Electroanalysis 12 (2000) 565] measured 0.08 nM higher iron concentrations than one FI?CL method [Anal. Chim. Acta 361 (1998) 189], which measured 0.13 nM higher iron values than the other two [Anal. Chem. 65 (1993) 1524; Anal. Chim. Acta 377 (1998) 113]. Statistical analyses (paired two-tailed t-test) showed that each analytical method gave significantly different dissolved iron concentrations at the 95% confidence interval. These data however, represent a significant improvement over earlier intercomparison exercises for iron. The data have been evaluated with respect to accuracy and overall inter-laboratory replicate precision, which was generally better than the 95% confidence intervals reported for the NASS Certified Reference Materials. Systematic differences between analytical methods were probably due to the extraction of different physico-chemical forms of iron during preconcentration, either on the micro-column resin (in the FI methods) or with competing ligand equilibration (in the CSV method). Small systematic concentration differences may also have resulted from protocols used for quantification of the analytical blank and instrument calibration. JF - Marine Chemistry VL - 84 KW - Dissolved iron KW - Seawater KW - Analytical intercomparison KW - Atlantic Ocean SN - 0304-4203 TI - Shipboard analytical intercomparison of dissolved iron in surface waters along a north-south transect of the tropical Atlantic Ocean SP - 19 AV - none EP - 34 ER - TY - JOUR ID - soton12542 UR - https://eprints.soton.ac.uk/12542/ IS - 4 A1 - Bowie, A.R. A1 - Whitworth, D.J. A1 - Achterberg, E.P. A1 - Mantoura, R.F.C. A1 - Worsfold, P.J. Y1 - 2002/// N2 - Iron and other trace metals (Al, Co, Ni) were measured through the upper water column during two north?south transects of the Atlantic Ocean (approximately 50°N?50°S), from the United Kingdom (UK) to the Falkland Islands (September/October 1996) and from South Africa to the UK (May/June 1998). Total dissolvable iron (TD-Fe) concentrations in the surface layers (<200 m) of the open Atlantic Ocean averaged 0.95±0.67 nM (n=142) during the 1996 cruise and 1.08±0.59 nM (n=160) during the 1998 cruise, with increased values in shelf waters at both extremes of the transects. Iron enrichments, fingerprinted via correlation with other trace metals, macronutrients and hydrography, correlated well with dry aerosol deposition off the west African continent and wet deposition in the Inter-Tropical Convergence Zone (ITCZ), with levels >2.2 nM observed in surface waters in these regions. Benthic fluxes provided a significant amount of Fe (2?38 nM) to the base of the water column in coastal zones. In addition, samples collected from one Atlantic Meridional Transect (AMT) expedition were re-analysed after a 16 month acidification period and showed significant increases over shipboard analyses (average values increasing to 2.26±1.50 nM), indicating the extended release of Fe from leachable particulate material in the stored samples. Detailed profiling through the euphotic zone revealed TD-Fe distributions that exhibited strong relationships with biological uptake, regeneration and water column hydrography. In equatorial and tropical North Atlantic waters, trace elemental distributions showed evidence of recent atmospheric deposition through a history of stratified mixed layers. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 49 KW - iron KW - trace metals KW - atlantic ocean KW - distributions KW - atmospheric and benthic inputs KW - phytoplankton uptake SN - 0967-0637 TI - Distribution of Fe and other trace elements (Al, Co and Ni) in the Atlantic Ocean SP - 605 AV - none EP - 636 ER - TY - JOUR ID - soton49668 UR - http://www.agu.org/journals/gl/gl0716/2007GL030126/ IS - 16 A1 - Boyer, T. A1 - Levitus, S. A1 - Antonov, J. A1 - Locarnini, R. A1 - Mishonov, A. A1 - Garcia, H. A1 - Josey, S.A. Y1 - 2007/08// N2 - Freshwater content changes (FW) for the North Atlantic Ocean (NA) are calculated from in situ salinity profiles for the period 1955?2006 from the surface to 2,000 meters. Heat content (HC) is also calculated from in situ temperature profiles for comparison. A decrease in FW between 1955 and 2006 of ~30,000 km3 is found for the NA, despite an increase in FW of ~16,000 km3 in the subpolar North Atlantic (SNA) and Nordic Seas between the late 1960s and the early 1990s. Over the last two decades there is a pattern of decreasing FW in the upper 400 meters and increasing FW below 1,300 meters for the NA. FW and HC are strongly negatively correlated for both the SNA (r = ?0.93) and the NA (r = ?0.79). Net precipitation, from NCEP/NCAR, is found to have a strong influence on FW changes in the SNA but this relation is weaker elsewhere. JF - Geophysical Research Letters VL - 34 KW - freshwater KW - Atlantic KW - salinity SN - 0094-8276 TI - Changes in freshwater content in the North Atlantic Ocean 1955?2006 AV - none ER - TY - JOUR ID - soton8722 UR - https://eprints.soton.ac.uk/8722/ IS - 1/2 A1 - Briais, A. A1 - Sloan, H. A1 - Parson, L.M. A1 - Murton, B.J. Y1 - 2000/// N2 - We analyse TOBI side-scan sonar images collected during Charles Darwin cruise CD76 in the axial valley of the Mid-Atlantic Ridge (MAR) between 27° N and 30° N (Atlantis Transform Fault). Mosaics of the two side-scan sonar swaths provide a continuous image of the axial valley and the inner valley walls along more than six second-order segments of the MAR. Tectonic and volcanic analyses reveal a high-degree intra-segment and inter-segment variability. We distinguish three types of volcanic morphologies: hummocky volcanoes or volcanic ridges, smooth, flat-topped volcanoes, and lava flows. We observe that the variations in the tectonics from one segment to another are associated with variations in the distribution of the volcanic morphologies. Some segments have more smooth volcanoes near their ends and in the discontinuities than near their mid-point, and large, hummocky axial volcanic ridges. Their tectonic deformation is usually limited to the edges of the axial valley near the inner valley walls. Other segments have smooth volcanoes distributed along their length, small axial volcanic ridges, and their axial valley floor is affected by numerous faults and fissures. We propose a model of volcano-tectonic cycles in which smooth volcanoes and lava flows are built during phases of high magmatic flux. Hummocky volcanic ridges are constructed more progressively, by extraction of magma from pockets located preferentially beneath the centre of the segments, during phases of low magma input. These cycles might result from pulses in melt migration from the mantle. Melt arrival would lead to the rapid emplacement of smooth-textured volcanic terrains, and would leave magma pockets, mostly beneath the centre of the segments where most melt is produced. During the end of the volcanic cycle magma would be extracted from these reservoirs through dikes with a low magma pressure, building hummocky volcanic ridges at low effusion rates. In extreme cases, this volcanic phase would be followed by amagmatic extension until a new magma pulse arrives from the mantle. JF - Marine Geophysical Researches VL - 21 KW - TOBI KW - OCEAN CRUST KW - MID ATLANTIC RIDGE KW - "CHARLES DARWIN" KW - CRUISE 76 1993 KW - SIDE SCAN SONAR SN - 0025-3235 TI - Accretionary processes in the axial valley of the Mid-Atlantic Ridge 27 degrees N - 30 degrees N from TOBI side-scan sonar images SP - 87 AV - none EP - 119 ER - TY - JOUR ID - soton43984 UR - https://eprints.soton.ac.uk/43984/ IS - 1-2 A1 - Brown, L. A1 - Sanders, R. A1 - Savidge, G. Y1 - 2006/// N2 - The standing stocks and production rates of particulate organic carbon (POC) and biogenic silica (bSiO2) were measured in the upper water column at 10 stations in the North East Atlantic during the spring 2001 diatom bloom. The elemental composition of the particulate pool was rather homogeneous with depth, suggesting that any material being exported from the photic zone was generally similar in composition to the ambient pool. Pronounced vertical structure was observed in uptake ratios resulting from the strong light dependence of the carbon fixation and the weak light dependence of biogenic silica production. The integrated C/Si molar ratios of particulate material were found to be generally larger than the corresponding assimilation ratios. We interpret this discrepancy as implying a preferential mineralization of Si relative to C from particulate matter during the earliest stages of processing in the upper water column. The preferential mineralisation of Si relative to C in the early stages of particle processing contrasts with processes occurring deeper in the water column, where C is typically mineralised preferentially to Si, and particulate matter becomes enriched in bSiO2. In the northern North Atlantic, the balance of mineralisation of Si relative to C from sinking organic matter with depth is likely to strongly influence the role of diatoms in export production.
JF - Journal of Marine Systems VL - 63 KW - diatom blooms KW - biogenic silica KW - particulate organic carbon KW - euphotic zone KW - mineralization KW - North Atlantic SN - 0924-7963 TI - Relative mineralisation of C and Si from biogenic particulate matter in the upper water column during the North East Atlantic diatom bloom in spring 2001 SP - 79 AV - none EP - 90 ER - TY - JOUR ID - soton2258 UR - https://eprints.soton.ac.uk/2258/ IS - 5 A1 - Brown, Louise A1 - Sanders, Richard A1 - Savidge, Graham A1 - Lucas, Cathy H. Y1 - 2003/// N2 - A full understanding of the biogeochemical cycling of silica in the North Atlantic is hampered by a lack of estimates of silica uptake by phytoplankton. We applied the 32Si radiotracer incubation technique to determine silica uptake rates at 10 sites during the UK-(Natural Environment Research Council) Faroes?Iceland?Scotland hydrographic and environmental survey (FISHES) cruise in the Northeast Atlantic, May 2001. Column silica uptake rates ranged between 6 and 166 mmol Si m-2 d-1; this data set was integrated with concurrent hydrographic, chemical, and primary productivity data to explain these changes in silica uptake in terms of the progress of the spring bloom. In order to interpret data covering a relatively large spatial and temporal scale, we used mean photic zone silica concentration as a proxy time-series measure of diatom bloom progression. Both absolute and specific silica uptake rates were highest at dissolved silica concentrations >2 µmol L-1. Si and C uptake were vertically decoupled at those stations where surface silica was strongly depleted. Absolute primary productivity was not strongly correlated with dissolved silica concentrations, owing to either exhaustion of silica at diatom-dominated stations or to dominance of the community by other phytoplankton. Silica uptake as a function of increased substrate concentration was linear up to 25 µmol L-1; we consider some possible reasons for the nonhyperbolic response. JF - Limnology and Oceanography VL - 48 KW - silica KW - northeast atlantic ocean KW - atlne KW - algal blooms KW - biomass KW - scotland waters KW - discovery KW - nweurheb KW - diatoms KW - primary production KW - hydrography KW - nutrients KW - biology SN - 0024-3590 TI - The uptake of silica during the spring bloom in the Northeast Atlantic Ocean SP - 1831 AV - restricted EP - 1845 ER - TY - JOUR ID - soton2144 UR - http://www.agu.org/pubs/crossref/2003/2001JB001172.shtml IS - B2 A1 - Bruguier, N.J. A1 - Minshull, T.A. A1 - Brozena, J.M. Y1 - 2003/// N2 - We present swath bathymetric, gravity, and magnetic data from the Mid-Atlantic Ridge between the Ascension and the Bode Verde fracture zones, where significant ridge?hot spot interaction has been inferred. The ridge axis in this region may be divided into four segments. The central two segments exhibit rifted axial highs, while the northernmost and southernmost segments have deep rift valleys typical of slow-spreading mid-ocean ridges. Bathymetric and magnetic data indicate that both central segments have experienced ridge jumps since ~1 Ma. Mantle Bouguer anomalies (MBAs) derived from shipboard free air gravity and swath bathymetric data show deep subcircular lows centered on the new ridge axes, suggesting that mantle flow has been established beneath the new spreading centers for at least ~1 Myr. Inversion of gravity data indicates that crustal thicknesses vary by ~4 km along axis, with the thickest crust occurring beneath a large axial volcanic edifice. Once the effects of lithospheric aging have been removed, a model in which gravity variations are attributed entirely to crustal thickness variations is more consistent with data from an axis-parallel seismic line than a model that includes additional along-axis variations in mantle temperature. Both geophysical and geochemical data from the region may be explained by the melting of small (<200 km) mantle chemical heterogeneities rather than elevated temperatures. Therefore, there may be no Ascension/Circe plume. JF - Journal of Geophysical Research: Solid Earth VL - 108 KW - SOUTH ATLANTIC OCEAN KW - GEOMORPHOLOGY KW - TECTONICS KW - MID ATLANTIC RIDGE KW - ATLS KW - SWATH BATHYMETRY KW - GRAVITY ANOMALIES KW - GEOLOGY TI - Morphology and tectonics of the Mid-Atlantic Ridge, 7°?12°S AV - public ER - TY - RPRT ID - soton297 UR - https://eprints.soton.ac.uk/297/ A1 - Bryden, H.L. Y1 - 1999/// N2 - The three principal objectives for RRS Discovery Cruise 232 were to carry out mooring operations associated with long-term monitoring of the exchange between the Atlantic and the Mediterranean through the Strait of Gibraltar, to study nonlinear processes resulting from the strong currents in the Strait with new instrumentation uniquely available on RRS Discovery, and to measure biogeochemical fluxes associated with the upper layer inflow of Atlantic water and the lower layer outflow of Mediterranean water through the Strait.

Eleven moorings deployed by scientists from Southampton Oceanography Centre (SOC), University of Malaga (UM), and Institut fur Meereskunde (IFM) in Kiel, who are cooperating in a two-year monitoring of the exchange through the Strait of Gibraltar using moored current meters under a multi-disciplinary CEC targeted programme called CANIGO, were scheduled for recovery during the cruise. Eight moorings were successfully recovered: two moorings were pre-released due to an error by an American collaborator and one mooring remains entangled with its anchor at the sill.

The principal nonlinear process studied was the development of a bore on the outgoing tide near the sill, its release as the tide turns, and its conversion into a nonlinear wave train as it propagates eastward into the Mediterranean. Dramatic signatures of 100m amplitude internal waves were measured by acoustic backscatter using EK500 underway profiling. Robust evidence for the waves was simultaneously derived from current profiles measured by the shipboard acoustic Doppler current profiler (ADCP), not only from the horizontal velocity but also from the directly measured vertical velocity, and from tow-yo CTD profiles up and down through the interfacial region between Atlantic and Mediterranean waters.

From hydrographic sections across the eastern and western entrances to the Strait of Gibraltar, we aimed to measure the biogeochemical fluxes through the Strait. Water samples analysed for oxygen, nutrients, chlorofluorocarbons, trace metals and dissolved organic carbon are to be combined with CTD and lowered ADCP velocity profiles to determine the fluxes directly. Such flux calculations represent a challenging sampling and analysis problem due to the tidal variations in the inflow and outflow currents as well as in the depth of the interface between the Mediterranean and Atlantic waters. PB - Southampton Oceanography Centre, University of Southampton KW - ACCP KW - ADCP KW - bioacoustics KW - biogeochemical fluxes KW - CANIGO KW - CFC KW - cruise 232 1998 KW - CTD observations KW - current meter measurements KW - Discovery KW - EK500 KW - Gibraltar Strait KW - hydraulics KW - inflow KW - internal waves KW - Mediterranean outflow KW - mixing KW - nonlinear processes KW - North Atlantic KW - nutrients KW - organic carbon KW - sill control KW - strait dynamics KW - trace metals KW - turbulence KW - water exchange M1 - project_report TI - RRS Discovery Cruise 232, 04 Apr-21 Apr 1998. Gibraltar exchange processes AV - public EP - 86 ER - TY - JOUR ID - soton19134 UR - https://eprints.soton.ac.uk/19134/ IS - 7068 A1 - Bryden, H.L. A1 - Longworth, H.R. A1 - Cunningham, S.A. Y1 - 2005/// N2 - The Atlantic meridional overturning circulation carries warm upper waters into far-northern latitudes and returns cold deep waters southward across the Equator. Its heat transport makes a substantial contribution to the moderate climate of maritime and continental Europe, and any slowdown in the overturning circulation would have profound implications for climate change. A transatlantic section along latitude 25° N has been used as a baseline for estimating the overturning circulation and associated heat transport. Here we analyse a new 25° N transatlantic section and compare it with four previous sections taken over the past five decades. The comparison suggests that the Atlantic meridional overturning circulation has slowed by about 30 per cent between 1957 and 2004. Whereas the northward transport in the Gulf Stream across 25° N has remained nearly constant, the slowing is evident both in a 50 per cent larger southward-moving mid-ocean recirculation of thermocline waters, and also in a 50 per cent decrease in the southward transport of lower North Atlantic Deep Water between 3,000 and 5,000 m in depth. In 2004, more of the northward Gulf Stream flow was recirculating back southward in the thermocline within the subtropical gyre, and less was returning southward at depth.
JF - Nature VL - 438 KW - gulf stream KW - ocean circulation KW - north atlantic current KW - climatic changes SN - 0028-0836 TI - Letter. Slowing of the Atlantic meridional overturning circulation at 25° N SP - 655 AV - restricted EP - 657 ER - TY - INPR ID - soton484880 UR - https://eprints.soton.ac.uk/484880/ A1 - Bryden, Harry A1 - Drijfhout, Sybren A1 - Hazeleger, Wilco A1 - Mecking, Jennifer Y1 - 2024/02/29/ N2 - The Coupled Model Intercomparison Project (CMIP) allows assessment of the representation of the Atlantic Meridional Overturning Circulation (AMOC) in climate models. While CMIP Phase 6 models display a large spread in AMOC strength by a factor of three, the multi-model mean strength agrees reasonably well with observed estimates from RAPID1, but this does not hold for its various components. In CMIP6 the present-day AMOC is characterised by a lack of lower North Atlantic Deep Water (lNADW), due to the small-scale of Greenland-Iceland-Scotland Ridge overflow and too much mixing. This is compensated by increased recirculation in the subtropical gyre and more Antarctic Bottom Water (AABW). Deep-water circulation is dominated by a distinct deep western boundary current (DWBC) with minor interior recirculation compared to observations. The future decline in the AMOC to 2100 of 7Sv under a SSP5-8.5 scenario is associated with decreased northward western boundary current transport in combination with reduced southward flow of upper North Atlantic Deep Water (uNADW). In CMIP6, wind stress curl decreases with time by 14% so that the wind-driven thermocline recirculation in the subtropical gyre is reduced by 4 Sv (17%) by 2100. The reduction in western boundary current transport of 11Sv is more than the decrease in the wind-driven gyre transport suggesting a decrease over time in the component of the Gulf Stream originating in the South Atlantic. JF - Ocean Science KW - ocean circulation KW - Atlantic Meridional Overturning Circulation (AMOC) KW - Climate model projections SN - 1812-0792 TI - Comparing observed and modelled components of the Atlantic Meridional Overturning Circulation at 26°N AV - public EP - 16 ER - TY - JOUR ID - soton455125 UR - https://eprints.soton.ac.uk/455125/ IS - 2256 A1 - Bryden, Harry L. Y1 - 2021/12/08/ N2 - Continuous observations of ocean circulation at 26°N in the subtropical Atlantic Ocean have been made since April 2004 to quantify the strength and variability in the Atlantic Meridional overturning circulation (AMOC), in which warm, upper waters flow northward and colder deep waters below 1100?m depth return southward. The principal components of the AMOC are northward western boundary current transport in the Gulf Stream and Antilles Current, northward surface Ekman transport and southward thermocline recirculation, all of which are generally considered to be part of the wind-driven circulation. Southward flowing deep waters below 1100?m depth are usually considered to represent the buoyancy-driven circulation. We argue that the Gulf Stream is partially wind-driven but also partially buoyancy-driven as it returns upper waters upwelled in the global ocean back to water mass formation regions in the northern Atlantic. Seasonal to interannual variations in the circulation at 26°N are principally wind-driven. Variability in the buoyancy-driven circulation occurred in a sharp reduction in 2009 in the southward flow of Lower North Atlantic Deep Water when its transport decreased by 30% from pre-2009 values. Over the 14-year observational period from 2004 to 2018, the AMOC declined by 2.4?Sv from 18.3 to 15.9?Sv. JF - Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences VL - 477 KW - Atlantic Meridional overturning circulation KW - Gulf Stream KW - Rapid observations KW - buoyancy-driven circulation KW - ocean circulation KW - wind-driven circulation SN - 1364-5021 TI - Wind-driven and buoyancy-driven circulation in the subtropical North Atlantic Ocean AV - public EP - 21 ER - TY - RPRT ID - soton42379 UR - https://eprints.soton.ac.uk/42379/ A1 - Burkill, P.H. Y1 - 2006/// N2 - The aim of this cruise was to develop a better understanding of carbon cycling in the pelagic waters of the Porcupine Abyssal Plain (PAP). There were three objectives 1) Turnaround moorings at the PAP Observatory; 2) Conduct a 1-D time series on the central station of a wide range of biogeochemical processes and to back this up with a mesoscale survey of key variables; 3) To trial the use of Autosub for mesoscale surveys in conjunction with the ship. All objectives were met, although the tops of the moorings were found to be missing probably due to fishing activity and the Autosub trials were incomplete due to vehicle failure. A full mesoscale survey was carried out using the ship and an eleven day time series at the central station was achieved. PB - National Oceanography Centre KW - Autosub KW - bacterioplankton KW - biogeochemistry KW - circulation KW - cruise 306 2006 KW - CTD KW - currents KW - Discovery KW - hydrography KW - moorings KW - NE Atlantic KW - nutrients KW - oxygen KW - PAP KW - phytoplankton KW - primary production KW - protozooplankton KW - SAPS KW - turbulence KW - zooplankton M1 - project_report TI - RRS Discovery Cruise 306, 23 Jun-06 Jul 2006. Pelagic biogeochemistry of the PAP Site AV - public EP - 92 ER - TY - JOUR ID - soton1293 UR - https://eprints.soton.ac.uk/1293/ IS - 2 A1 - Buss de Souza, R. A1 - Robinson, I.S. Y1 - 2004/// N2 - The waters dominating the Brazilian Continental Shelf to the south of Santa Marta Cape (28[deg]40'S) are marked by their strong interannual variability. Both the seasonal oscillation of the Brazil-Malvinas (Falkland) Confluence (BMC) region and the seasonal variations of the La Plata River and Patos Lagoon outflows are reflected in the seasonal changes of the vertical and horizontal water mass structure in the Southern Brazilian Shelf. In the region to the north of Santa Marta Cape, the shelf is mainly described in the literature as dominated by Tropical Waters (TW) transported southwards by the Brazil Current (BC). However, the first Lagrangian (buoy) measurements made on the inner Brazilian shelf have shown that a coastal current flowing in the opposite direction in relation to the BC occurred on the shelf as far north as 24[deg]S during the 1993 austral autumn and winter. Recent papers have suggested that the arrival at low latitudes of cold waters originating in the BMC region is an anomalous phenomenon and that it can be either forced by local winds during wintertime or related to the ENSO. High-resolution sea surface temperature (SST) imagery and the Lagrangian measurements taken in 1993 and 1994 are used in this paper to describe the temperatures, velocity, energy and oscillations present in this coastal current. These two data sets show that the current is not only fed by waters of Subantarctic or coastal origin but also receives a contribution of TW at the surface by lateral mixing. By analysing a set of monthly averaged SST images from 1982 to 1995, this work suggests that the intrusion of cold waters transported by the coastal current can be a regular winter phenomenon occurring on the Brazilian shelf at latitudes up to the vicinity of 25[deg]S. Given its consistency, this current is named here the Brazilian Coastal Current. JF - Continental Shelf Research VL - 24 KW - south-western atlantic KW - southern brazilian shelf KW - surface currents KW - drifting buoys KW - avhrr KW - coroas KW - woce SN - 0278-4343 TI - Lagrangian and satellite observations of the Brazilian Coastal Current SP - 241 AV - none EP - 262 ER - TY - JOUR ID - soton361634 UR - https://eprints.soton.ac.uk/361634/ IS - 5 A1 - Butler, I.B. A1 - Fallick, A.E. A1 - Nesbitt, R.W. Y1 - 1998/// N2 - A large collection of hydrothermal sulphides from the Broken Spur hydrothermal vent site, including representative samples of mound sulphide materials, has been characterized using optical mineralogy and sulphur isotope analysis. Young mound sulphides from Broken Spur have a pyrrhotite-dominated mineralogy unusual for bare ridge vent systems. However, pyrrhotite is metastable and is ultimately converted to iron disulphides. Mature sulphides are indurated, recrystallized and contain abundant quartz. Sulphide mound materials are developed by three major processes: (i) coalescing of chimney structures; (ii) accumulation of talus from mass wasting and (iii) precipitation and growth in response to hydrothermal flow. Progressive maturation of mound materials is by modification of primary textures, development of mineralogical zoning and replacement of metastable phases. Sulphur isotope analysis of 35 mineral separates returned ?34S values of ? 0.5 to +3.2?. These values are similar to those previously measured for Broken Spur and Snakepit, but are distinctly 32S enriched compared to the TAG active mound and some Pacific sites. Seawater entrainment and sulphate reduction within the subsurface feeder zone below Broken Spur mounds do not appear to be important processes at Broken Spur, in contrast to the TAG active mound. JF - Journal of the Geological Society VL - 155 KW - Mid-Atlantic Ridge KW - sulphides KW - sulphur KW - isotopes KW - hydrothermal vents SN - 0016-7649 TI - Mineralogy, sulphur isotope geochemistry and the development of sulphide structures at the Broken Spur hydrothermal vent site, 29 10'N, Mid-Atlantic Ridge SP - 773 AV - none EP - 785 ER - TY - JOUR ID - soton18697 UR - http://www.copernicus.org/EGU/os/os/1/97/os-1-97.pdf IS - 2 A1 - Caltabiano, A.C.V. A1 - Robinson, I.S. A1 - Pezzi, L.P. Y1 - 2005/10/21/ N2 - Instability waves in the tropical Atlantic Ocean are analysed by microwave satellite-based data spanning from 1998 to 2001. This is the first multi-year observational study of the sea surface temperature (SST) signature of the Tropical Instability Waves (TIW) in the region. SST data were used to show that the waves spectral characteristics vary from year-to-year. They also vary on each latitude north of the equator, with the region of 1° N, 15° W concentrating the largest variability when the time series is averaged along the years. Analyses of wind components show that meridional winds are more affected near the equator and 1° N, while zonal winds are more affected further north at around 3° N and 4° N. Concurrent observations of SST, wind, atmospheric water vapour, liquid cloud water, precipitation rates and wind were used to suggest the possible influence of these waves on the Intertropical Convergence Zone (ITCZ). It seems that these instabilities have a large impact on the ITCZ due to its proximity of the equator, compared to its Pacific counterpart, and the geography of the tropical Atlantic basin. These analyses also suggest that the air-sea coupling mechanism suggested by Wallace can also be applied to the tropical Atlantic region. JF - Ocean Science VL - 1 KW - sea surface temperature KW - satellite KW - topical instability waves KW - tropical Atlantic SN - 1812-0792 TI - Multi-year satellite observations of instability waves in the Tropical Atlantic Ocean SP - 97 AV - none EP - 112 ER - TY - JOUR N1 - Funding Information: This research forms part of the CHANCE project, which is supported by awards from the UK Natural Environment Research Council (NE/S010262/1) and US National Science Foundation (1929382). We would like to thank Dirk Eilander for providing support about the use of dataset of simulated water levels and discharge at river mouth locations globally which is available on Zenodo (doi: 10.5281/zenodo.3665734 ). Funding Information: US National Science Foundation, Grant/Award Number: 1929382; UK Natural Environment Research Council, Grant/Award Number: NE/S010262/1 Funding information Publisher Copyright: © 2022 The Authors. International Journal of Climatology published by John Wiley & Sons Ltd on behalf of Royal Meteorological Society. ID - soton455185 UR - https://eprints.soton.ac.uk/455185/ IS - 11 A1 - Camus Brana, Paula A1 - Haigh, Ivan A1 - Wahl, Thomas A1 - Nasr, Ahmed A. A1 - Mendez, Fernando A1 - Darby, Stephen A1 - Nicholls, Robert Y1 - 2022/09// N2 - Coastal compound flooding events occur when extreme events of rainfall, river discharge and sea level coincide and collectively increase water surface elevation, exacerbating flooding. The meteorological conditions that generate these events are usually low-pressure systems that generate high winds and intense rainfall. In this study, we identify the types of synoptic atmospheric conditions that are typically associated with coastal compound events using a weather-type approach, for the North Atlantic coastlines (encompassing northwest Europe and the east coast of the United States). Compound events are identified along the estuaries of the study region from 1980 to 2014 based on an impact function defined by water surface elevation that resulted from the combination of river discharge and sea level. We find that compound events are more frequent along European as opposed to U.S. coastlines. In both cases, they are associated with a few dominant weather patterns. European hotspots of compound events are concentrated in the west coast of United Kingdom, the northwest coast of the Iberian Peninsula and around the Strait of Gibraltar. These areas share the same weather patterns which represent the main pathways of storms that cross the North Atlantic Ocean. In the case of U.S. locations, the areas with highest number of compound events are located mainly in the Gulf of Mexico and along Mexico and along the mid-eastern U.S. coastlines. In these areas, compound events are produced by transitional weather patterns, which describe storms that travel northward parallel to the coastline. Splitting the occurrence of compound events in the corresponding weather types discriminates the interannual variability based on the relationship with dominant climate indices in the North Atlantic Ocean. JF - International Journal of Climatology VL - 42 KW - North Atlantic KW - coastal flooding KW - compound events KW - estuaries KW - weather types TI - Daily synoptic conditions associated with occurrences of compound events in estuaries along North Atlantic coastlines SP - 5694 AV - public EP - 5713 ER - TY - JOUR N1 - Funding Information: This study is a contribution to OVIDE (co-funded by the IFREMER, CNRS/INSU/LEFE), Blue-Action (EU Horizon 2020 grant agreement No 727852), ABC-Fluxes (NERC-funded grant No NE/M005046/1) projects, and CLASS (NERC National Capability Science Single Centre awards) programme. This study was supported by the TRIATLAS project (EU Horizon 2020 grant agreement No 817578). L. I. Carracedo supported by the University of Vigo through the Galician I2C Plan for postdoctoral research, NERC within the framework of the ABC-Fluxes Project, and IFREMER. H. Mercier was financed by CNRS; E. McDonagh and R. Sanders by NERC and NORCE; G. Ros?n by the University of Vigo; C. M. Moore and P. Brown by NERC; S.Torres-Vald?s by AWI; P. Lherminier by IFREMER; and F. F. P?rez by the BOCATS2 project (PID2019-104279GB-C21) co-funded by the Spanish Government and the FEDER, and by the COMFORT project (EU Horizon 2020 grant agreement No 820989). The authors are grateful to the captains, crew, technicians, and scientists who contributed to the acquisition, processing, and quality control of the hydrographic data used in this study. The authors particularly thank P. Zunino for her valuable contribution to the OVIDE data interpolation. Funding Information: This study is a contribution to OVIDE (co?funded by the IFREMER, CNRS/INSU/LEFE), Blue?Action (EU Horizon 2020 grant agreement No 727852), ABC?Fluxes (NERC?funded grant No NE/M005046/1) projects, and CLASS (NERC National Capability Science Single Centre awards) programme. This study was supported by the TRIATLAS project (EU Horizon 2020 grant agreement No 817578). L. I. Carracedo supported by the University of Vigo through the Galician I2C Plan for postdoctoral research, NERC within the framework of the ABC?Fluxes Project, and IFREMER. H. Mercier was financed by CNRS; E. McDonagh and R. Sanders by NERC and NORCE; G. Rosón by the University of Vigo; C. M. Moore and P. Brown by NERC; S.Torres?Valdés by AWI; P. Lherminier by IFREMER; and F. F. Pérez by the BOCATS2 project (PID2019?104279GB?C21) co?funded by the Spanish Government and the FEDER, and by the COMFORT project (EU Horizon 2020 grant agreement No 820989). The authors are grateful to the captains, crew, technicians, and scientists who contributed to the acquisition, processing, and quality control of the hydrographic data used in this study. The authors particularly thank P. Zunino for her valuable contribution to the OVIDE data interpolation. Publisher Copyright: © 2021. The Authors. ID - soton449171 UR - https://eprints.soton.ac.uk/449171/ IS - 6 A1 - Carracedo, L.I. A1 - Mercier, H. A1 - McDonagh, E. A1 - Rosón, G. A1 - Sanders, R. A1 - Moore, Christopher A1 - Torres?Valdés, S. A1 - Brown, P. A1 - Lherminier, P. A1 - Pérez, F.F. Y1 - 2021/06// N2 -

The North Atlantic Basin is a major sink for atmospheric carbon dioxide (CO 2) due in part to the extensive plankton blooms which form there supported by nutrients supplied by the three-dimensional ocean circulation. Hence, changes in ocean circulation and/or stratification may influence primary production and biological carbon export. In this study, we assess this possibility by evaluating inorganic nutrient budgets for 2004 and 2010 in the North Atlantic based on observations from the transatlantic A05-24.5°N and the Greenland-Portugal OVIDE hydrographic sections, to which we applied a box inverse model to solve the circulation and estimate the across-section nutrient transports. Full water column nutrient budgets were split into upper and lower meridional overturning circulation (MOC) limbs. According to our results, anomalous circulation in early 2010, linked to extreme negative NAO conditions, led to an enhanced northward advection of more nutrient-rich waters by the upper overturning limb, which resulted in a significant nitrate and phosphate convergence north of 24.5°N. Combined with heaving of the isopycnals, this anomalous circulation event in 2010 favored an enhancement of the nutrient consumption (5.7 ± 4.1 kmol-P s ?1) and associated biological CO 2 uptake (0.25 ± 0.18 Pg-C yr ?1, upper-bound estimate), which represents a 50% of the mean annual sea?air CO 2 flux in the region. Our results also suggest a transient state of deep silicate divergence in both years. Both results are indicative of a MOC-driven modulation of the biological carbon uptake (by the upper MOC limb) and nutrient inventories (by the lower MOC limb) in the North Atlantic.

JF - Global Biogeochemical Cycles VL - 35 KW - Carbon cycle KW - North Atlantic KW - Nutrient and oxygen transports KW - Nutrient budgets KW - Nutrient cycles KW - Overturning circulation SN - 0886-6236 TI - Counteracting contributions of the upper and lower meridional overturning limbs to the North Atlantic nutrient budgets: enhanced imbalance in 2010 AV - public EP - 46 ER - TY - JOUR ID - soton427499 UR - https://eprints.soton.ac.uk/427499/ A1 - Carter, Gareth D.O. A1 - Huvenne, Veerle A.I. A1 - Gales, Jennifer A. A1 - Lo Iacono, Claudio A1 - Marsh, Leigh A1 - Ougier-Simonin, Audrey A1 - Robert, Katleen A1 - Wynn, Russell B. Y1 - 2018/12// N2 -

During the CODEMAP 2015 research expedition to the Whittard Canyon, Celtic Margin (NE Atlantic), a Remotely Operated Vehicle (ROV) gathered High Definition video footage of the canyon rockwalls at depths of approximately 412?4184 m below sea level. This dataset was supplemented by predominantly carbonate rock samples collected during the dives, which were subsequently tested for key physical property characteristics in a geotechnical laboratory. The high-resolution video footage revealed small-scale rockwall slope processes that would not have been visible if shipboard geophysical equipment was solely relied upon during the survey. Of particular interest was the apparent spalling failure of mudstone and chalk rockwalls, with fresh superficial ?flaking? scars and an absence of sessile fauna possibly suggesting relatively recent mass-wasting activity. Extensive talus slopes, often consisting of coarse gravel, cobble and occasionally boulder-sized clasts, were observed at the foot of slopes impacted by spalling failures; this debris was rarely colonised by biological communities, which could be an indicator of frequent rockfall events. Bio-erosion was also noted on many of the walls prone to this form of rock slope failure (RSF). As in subaerial equivalents, internal fracture networks appear to control the prevalence of RSF and the geometries of blocks, often resulting in cubic and tabular blocks (0.2?1.0 m scale) of bedrock toppling or sliding out of the cliff face. Tensile strength parameters of carbonate rock samples were determined and these may affect the mass wasting processes observed within the canyon. It was found that carbonate samples which appeared to have a higher mud content, and reduced porosity, produced significantly higher tensile strength values. It is proposed that these stronger, ?muddy? carbonate units form the overhanging ledges that often provide an ideal setting for sessile species, such as Acesta excavata clams, to colonise whereas the weaker ?pure? carbonate units are more easily eroded and therefore form the undercutting, receding sections of the rockwall. By combining the ROV observations, basic discontinuity assessments (estimation of fracture orientations) and laboratory testing results, an understanding of the geomechanical properties of the bedrock can be obtained and linked with past and ongoing rock slope processes within the Whittard Canyon. These conclusions will have a wider implication for ongoing geomechanical processes within submarine canyons on a global scale.

JF - Progress in Oceanography VL - 169 KW - Bedrock erosion KW - Bioerosion KW - Canyon rockwalls KW - Celtic Margin KW - NE Atlantic KW - Remotely Operated Vehicle KW - Submarine canyons KW - Whittard Canyon SN - 0079-6611 TI - Ongoing evolution of submarine canyon rockwalls; examples from the Whittard Canyon, Celtic Margin (NE Atlantic) SP - 79 AV - none EP - 88 ER - TY - RPRT ID - soton19312 UR - https://eprints.soton.ac.uk/19312/ Y1 - 2004/10// PB - International CLIVAR Project Office T3 - No. 31 (Vol. 9(3) KW - CLIVAR KW - WCRP KW - Exchanges KW - newsletter KW - Atlantic predictability ED - Cattle, H. M1 - project_report TI - CLIVAR Exchanges No. 31. Atlantic Predictability AV - public EP - 32 ER - TY - JOUR ID - soton5991 UR - https://eprints.soton.ac.uk/5991/ IS - 11 A1 - Cave, R.R. A1 - German, C.R. A1 - Thomson, J. A1 - Nesbitt, R.W. Y1 - 2002/// N2 - A geochemical investigation has been conducted of a suite of four sediment cores collected from directly beneath the hydrothermal plume at distances of 2 to 25 km from the Rainbow hydrothermal field. As well as a large biogenic component (>80% CaCO3) these sediments record clear enrichments of the elements Fe, Cu, Mn, V, P, and As from hydrothermal plume fallout but only minor detrital background material. Systematic variations in the abundances of "hydrothermal" elements are observed at increasing distance from the vent site, consistent with chemical evolution of the dispersing plume. Further, pronounced Ni and Cr enrichments at specific levels within each of the two cores collected from closest to the vent site are indicative of discrete episodes of additional input of ultrabasic material at these two near-field locations. Radiocarbon dating reveals mean Holocene accumulation rates for all four cores of 2.7 to 3.7 cm.kyr?1, with surface mixed layers 7 to 10+ cm thick, from which a history of deposition from the Rainbow hydrothermal plume can be deduced. Deposition from the plume supplies elements to the underlying sediments that are either directly hydrothermally sourced (e.g., Fe, Mn, Cu) or scavenged from seawater via the hydrothermal plume (e.g., V, P, As). Holocene fluxes into to the cores? surface mixed layers are presented which, typically, are an order of magnitude greater than "background" authigenic fluxes from the open North Atlantic. One core, collected closest to the vent site, indicates that both the concentration and flux of hydrothermally derived material increased significantly at some point between 8 and 12 14C kyr ago; the preferred explanation is that this variation reflects the initiation/intensification of hydrothermal venting at the Rainbow hydrothermal field at this time?perhaps linked to some specific tectonic event in this fault-controlled hydrothermal setting. JF - Geochimica et Cosmochimica Acta VL - 66 KW - SEDIMENTS KW - FLUX KW - HYDROTHERMAL PLUMES KW - MID ATLANTIC RIDGE KW - HOLOCENE SN - 0016-7037 TI - Fluxes to sediments underlying the Rainbow hydrothermal plume at 36°14?N on the Mid-Atlantic Ridge SP - 1905 AV - none EP - 1923 ER - TY - JOUR ID - soton2035 UR - https://eprints.soton.ac.uk/2035/ IS - 1-2 A1 - Cave, R.R. A1 - Ravizza, G.E. A1 - German, C.R. A1 - Thomson, J. A1 - Nesbitt, R.W. Y1 - 2003/// N2 - Osmium and other platinum-group elements (PGEs) have been measured in sediments accumulating directly under the Rainbow hydrothermal plume at 36[deg]N on the Mid-Atlantic Ridge. 187Os/188Os and PGE concentrations in the sediments of four cores taken 2-25 km from the active vent site reveal evidence of both radiogenic Os scavenged from seawater and, importantly, unradiogenic Os released by hydrothermal venting. The majority of analyses (n=16) yield 187Os/188Os ratios that fall in a narrow range (0.99-1.06) close to that of modern seawater. In these samples, Os concentrations correlate linearly with hydrothermal V enrichments, which are also derived from seawater scavenging. A smaller subset of samples, characterized by unusually high concentrations of Ni and Cr derived from ultramafic rock fragments, exhibit distinctly lower 187Os/188Os ratios. Their Ir content is also higher, and their PGE ratios are more similar to mantle material than the PGE patterns of the larger set of samples dominated by seawater-scavenged Os. Although the two most proximal cores lack evidence for any similar ultramafic 'detritus' in their surficial sediments, 187Os/188Os ratios in these samples are also lower than that of ambient seawater, suggesting they are likely to have been influenced by unradiogenic Os from vent fluid incorporated into the plume. Samples from the most distal core, by contrast, exhibit 187Os/188Os ratios indistinguishable from that of seawater. Compared with 'background' NE Atlantic sediments, Os is enriched four-fold in the seawater-dominated samples, while Pd, Pt and Ir are twice the background value. Burial fluxes of Os scavenged by hydrothermal Fe in these sediments are 200-400 pg cm-2 kyr-1, up to twice that found on the EPR, and several times the background (bg) of 50 pg cm-2 kyr-1. For Pt, burial fluxes are 1800-3000 pg cm-2 kyr-1 (bg ca. 1000 pg cm-2 kyr-1) and for Pd 2700-4600 pg.cm-2 kyr-1 (bg ca. 800 pg cm-2 kyr-1) JF - Earth and Planetary Science Letters VL - 210 KW - SEDIMENTS KW - MID ATLANTIC RIDGE KW - OSMIUM KW - GEOLOGY SN - 0012-821X TI - Deposition of osmium and other platinum-group elements beneath the ultramafic-hosted rainbow hydrothermal plume SP - 65 AV - none EP - 79 ER - TY - JOUR ID - soton427507 UR - https://eprints.soton.ac.uk/427507/ A1 - Chalk, T. B. A1 - Foster, G. L. A1 - Wilson, P. A. Y1 - 2019/03/15/ N2 -

The origin and carbon content of the deep water mass that fills the North Atlantic Basin, either Antarctic Bottom Water (AABW) or North Atlantic Deep Water (NADW) is suggested to influence the partitioning of CO2 between the ocean and atmosphere on glacial?interglacial timescales. Fluctuations in the strength of Atlantic meridional overturning circulation (AMOC) have also been shown to play a key role in global and regional climate change on timescales from annual to millennial. The North Atlantic is an important and well-studied ocean basin but many proxy records tracing ocean circulation in this region over the last glacial cycle are challenging to interpret. Here we present new B/Ca-[CO3 2?] and boron isotope-pH data from sites spanning the North Atlantic Ocean from 2200 to 3900 m and covering the last 130 kyr from both sides of the Mid-Atlantic Ridge. These data allow us to explore the potential of the boron-based proxies as tracers of ocean water masses to ultimately identify the changing nature of Atlantic circulation over the last 130 kyr. This possibility arises because the B/Ca and boron isotope proxies are directly and quantitatively linked to the ocean carbonate system acting as semi-conservative tracers in the modern ocean. Yet the utility of this approach has yet to be demonstrated on glacial?interglacial timescales when various processes may alter the state of the deep ocean carbonate system. We demonstrate that the deep (?3400 m) North Atlantic Ocean exhibits considerable variability in terms of its carbonate chemistry through the entirety of the last glacial cycle. Our new data confirm that the last interglacial marine isotope stage (MIS) 5e has a similar deep-water geometry to the Holocene, in terms of the carbonate system. In combination with benthic foraminiferal ?13C and a consideration of the [CO3 2?] of contemporaneous southern sourced water, we infer that AABW influences the eastern abyssal North Atlantic throughout the whole of the last glacial (MIS2 through 4) whereas, only in the coldest stages (MIS2 and MIS4) of the last glacial cycle was AABW an important contributor to our deep sites in both North Atlantic basins. Taken together, our carbonate system depth profiles reveal a pattern of changing stratification within the North Atlantic that bears strong similarities to the atmospheric CO2 record, evidencing the important role played by ocean water mass geometry and the deep ocean carbonate system in driving changes in atmospheric CO2 on these timescales.

JF - Earth and Planetary Science Letters VL - 510 KW - Atlantic KW - boron KW - carbonate system KW - geochemistry KW - glacial KW - palaeoceanography SN - 0012-821X TI - Dynamic storage of glacial CO2 in the Atlantic Ocean revealed by boron [CO3 2?] and pH records SP - 1 AV - public EP - 11 ER - TY - JOUR ID - soton120 UR - https://eprints.soton.ac.uk/120/ IS - 9 A1 - Challenor, P.G. A1 - Cipollini, P. A1 - Cromwell, D. Y1 - 2001/// N2 - One of the most successful applications of satellite-borne radar altimeter data over the oceans in recent years has been the extraction of information about long-wavelength baroclinic Rossby (or planetary) waves, which play a significant role in ocean circulation and climate dynamics. These waves cross ocean basins from east to west at speeds of few centimetres per second at mid-latitudes. The cross-basin propagation time may therefore be several months or even years and an accurate estimation of the speed of the waves is important. We review the methods for obtaining information on Rossby wave velocity from altimetry data, particularly the two-dimensional Radon transform. Unfortunately the use of longitude-time plots, although it allows the estimation of the zonal phase speeds, does not give any information on the speed vector when the propagation of the waves is not purely zonal (east-west). We show how the two-dimensional Radon Transform can be generalised to three dimensions, enabling not only the true propagation velocity component to be determined, but also the direction of the waves and thus any deviation from the pure-westward case. As examples of the application of this extended technique, we show maps of direction, speed and energy of Rossby waves in the North Atlantic Ocean. JF - Journal of Atmospheric and Oceanic Technology VL - 18 KW - planetary waves KW - rossby waves KW - radon transform KW - north atlantic ocean SN - 0739-0572 TI - Use of the 3D radon transform to examine the properties of oceanic Rossby waves SP - 1558 AV - public EP - 1566 ER - TY - JOUR ID - soton187599 UR - https://eprints.soton.ac.uk/187599/ A1 - Chavtur, Vladimir G. A1 - Angel, Martin V. Y1 - 2011/// N2 - A new tribe of pelagic Ostracoda (Halocyprididae), the Metaconchoeciini, is established to encompass all the species formerly classified in the genus Metaconchoecia. All the remaining genera in the subfamily Conchoecinae are, therefore, assigned to another new tribe, the Conchoeciini. The original genus Metaconchoecia is subdivided into ten genera. Metaconchoecia is retained and nine new genera established namely: Austrinoecia, Clausoecia, Deeveyoecia, Juryoecia, Kyrtoecia, Muelleroecia, Nasoecia, Rotundoecia and Vityazoecia. Keys to these new genera and their component species are provided. Tables summarize the characters that most readily distinguish between the most closely related taxa. Appendices summarize the taxonomic characters and detailed size data for the majority of species that occur in the Atlantic and the North Pacific. A new species, Vityazoecia distoglandula, is described, which is designated as the type species of its genus. JF - Zootaxa VL - 2857 KW - morphology KW - taxonomy KW - zooplankton KW - oceanic KW - Atlantic KW - North Pacific KW - Vityazoecia distoglandula n. sp. SN - 1175-5334 TI - Revision of Metaconchoecia (Ostracoda: Halocyprididae) and the designation of two new tribes Conchoeciini and Metaconchoeciini SP - 1 AV - none EP - 87 ER - TY - JOUR ID - soton373087 UR - https://eprints.soton.ac.uk/373087/ A1 - Chen, Xinping A1 - Dangendorf, Sönke A1 - Narayan, Nikesh A1 - O'Driscoll, Kieran A1 - Tsimplis, Michael N. A1 - Su, Jian A1 - Mayer, Bernhard A1 - Pohlmann, Thomas Y1 - 2014/12/04/ N2 - In this study, contributions of both local steric and remote baroclinic effects (i.e., steric variations external to the region of interest) to the inter-annual variability of winter sea level in the North Sea, with respect to the North Atlantic Oscillation (NAO), for the period of 1953?2010 are investigated. On inter-annual time scales in this period, the NAO is significantly correlated to sea level variations in the North Sea only in the winter months (December?March), while its correlation to sea temperature over much of the North Sea is only significant in January and February. The discrepancy in sea level between observations and barotropic tide and surge models forced by tides and local atmospheric forcing, i.e., local atmospheric pressure effects and winds, in the present study are found to be consistent with previous studies. In the North Sea, local thermosteric effects caused by thermal expansion play a minor role on winter-mean NAO related sea level variability compared with atmospheric forcing. This is particularly true in the southeastern North Sea where water depths are mostly less than 25 m. Our calculations demonstrate that the discrepancy can be mostly explained by remote baroclinic effects, which appear as water mass exchanges on the continental shelf and are therefore only apparent in ocean bottom pressure. In the North Sea, NAO related sea level variations seem to be a hybrid of barotropic and baroclinic processes. Hence, they can only be adequately modelled with three-dimensional baroclinic ocean models that include contributions of baroclinic effects and large-scale atmospheric forcing external to the region of interest. JF - Estuarine, Coastal and Shelf Science VL - 151 KW - North Sea KW - sea level KW - North Atlantic Oscillation KW - steric effect KW - baroclinic effect SN - 0272-7714 TI - On sea level change in the North Sea influenced by the North Atlantic Oscillation: Local and remote steric effects SP - 186 AV - public EP - 195 ER - TY - JOUR N1 - Funding Information: The authors thank the captain and crew of the RSS Discovery for their assistance during research expeditions and Malcolm Woodward and Carolyn Harrys for the macronutrient data. This project was funded by the UK Natural Environment Research Council (NE/K001973/1 (E. A. and M. G.), NE/K001779/1 (M. L.), NE/K002023/1 (A. A.), and NE/L501840/1 (A. B.)), and by GEOMAR. Publisher Copyright: © 2023 Elsevier Ltd ID - soton477219 UR - https://eprints.soton.ac.uk/477219/ A1 - Chen, Xue-Gang A1 - Rusiecka, Dagmara A1 - Gledhill, Martha A1 - Milne, Angela A1 - Annett, Amber A1 - Beck, Aaron Joseph A1 - Birchill, A.J. A1 - Lohan, Maeve C. A1 - Ussher, Simon A1 - Achterberg, Eric P. Y1 - 2023/05/01/ N2 - Dissolved (<0.2 ?m) trace metals (dTMs) including iron (Fe), manganese (Mn), and cobalt (Co) are micronutrients that (co-) limit phytoplankton growth in many ocean regions. Here, we present the spatial and seasonal distributions of dFe, dMn, and dCo on the Northeast Atlantic continental margin (Celtic Sea), along a transect across the shelf and two off-shelf transects along a canyon and a spur. Waters on the continental shelf showed much higher dTM concentrations (dFe 0.07?6.50 nmol L?1, average 1.41 ± 0.96 nmol L?1, n = 138; dMn 0.868?14.8 nmol L?1, 2.75 ± 2.37 nmol L?1, n = 148; dCo 54.8?217 pmol L?1, 109 ± 32 pmol L?1, n = 144) than on the slope (dFe 0.03?1.90 nmol L?1, 0.65 ± 0.43 nmol L?1, n = 454; dMn 0.223?1.14 nmol L?1, 0.58 ± 0.20 nmol L?1, n = 458; dCo 27.3?122 pmol L?1, 71.7 ± 11.7 pmol L?1, n = 441), attributed to strong dTM contributions from a low-salinity endmember, i.e., riverine discharge. Benthic sedimentary input via reductive dissolution (especially for dFe and dMn), delineated by short-lived radium (Ra) isotopic activities (223Raxs and 224Raxs), was only prominent at a station (Site A) characterized by fine sediments. On the continental slope, dMn levels at depth were mainly determined by the formation of insoluble Mn oxides and the intrusion of Mediterranean Outflow Waters. In contrast, dFe and dCo concentrations at depth were balanced by the regeneration from remineralization of sinking organic particles and scavenging removal. In addition, bottom and intermediate nepheloid layers along the slope illustrated both elevated dTM concentrations and Ra isotopic activities. The presence of nepheloid layers is especially significant along the canyon transect relative to the spur transect, demonstrating the importance of slope topography on the off-shelf transport of dTMs into the Northeast Atlantic Ocean.

As a seasonal stratified shelf sea, dTMs and nutrients showed synchronized seasonal variations on the shelf, indicating the influence of biological processes in addition to source effects. Surface dFe and dCo were depleted in summer due to enhanced biological uptake, while sub-surface dFe and dCo were elevated in summer and autumn ascribed to the remineralization of sinking organic particles. In contrast, surface dMn levels were predominantly controlled by the seasonal variations in photoreduction, while sub-surface dMn concentrations were relatively constant throughout the year. The combined effects of fluvial and benthic sources, topographical controls, and biological processes shape the seasonal variations of dTM distributions. Such seasonal variations in dTMs and biological activities can affect the biological carbon pump on the Northeast Atlantic continental margin, and may further influence the carbon cycle in the Atlantic Ocean via the dynamic dTM exchange between continental margins and the open ocean. JF - Geochimica et Cosmochimica Acta VL - 348 KW - Dissolved trace metals KW - North Atlantic KW - Radium isotopes KW - Remineralization KW - Seasonal variation SN - 0016-7037 TI - Physical and biogeochemical controls on seasonal iron, manganese, and cobalt distributions in Northeast Atlantic shelf seas SP - 278 AV - public EP - 295 ER - TY - JOUR ID - soton350713 UR - https://eprints.soton.ac.uk/350713/ A1 - Cianca, A. A1 - Santana, R. A1 - Hartman, S.E. A1 - Martín-González, J.M. A1 - González-Dávila, M. A1 - Rueda, M.J. A1 - Llinás, O. A1 - Neuer, S. Y1 - 2013/09// N2 - Dissolved oxygen (DO) in the ocean is a tracer for most ocean biogeochemical processes including net community production and remineralization of organic matter which in turn constrains the biological carbon pump. Knowledge of oxygen dynamics in the North Atlantic Ocean is mainly derived from observations at the Bermuda Atlantic Time-series Study (BATS) site located in the western subtropical gyre which may skew our view of the biogeochemistry of the subtropical North Atlantic. This study presents and compares a 15 yr record of DO observations from ESTOC (European Station for Time-Series in the Ocean, Canary Islands) in the eastern subtropical North Atlantic with the 20 yr record at BATS. Our estimate for net community production of oxygen was 2.3±0.4 mol O2 m?2 yr?1 and of oxygen consumption was ?2.3±0.5 mol O2 m?2 yr?1 at ESTOC, and 4 mol O2 m?2 yr?1 and ?4.4±1 mol m?2 yr?1 at BATS, respectively. These values were determined by analyzing the time-series using the Discrete Wavelet Transform (DWT) method. These flux values agree with similar estimates from in-situ observational studies but are higher than those from modeling studies. The difference in net oxygen production rates supports previous observations of a lower carbon export in the eastern compared to the western subtropical Atlantic. The inter-annual analysis showed clear annual cycles at BATS whereas longer cycles of nearly 4 years were apparent at ESTOC. The DWT analysis showed trends in DO anomalies dominated by long-term perturbations at a basin scale for the consumption zones at both sites, whereas yearly cycles dominated the production zone at BATS. The long-term perturbations found are likely associated with ventilation of the main thermocline, affecting the consumption and production zones at ESTOC. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 93 KW - Oxygen KW - Production KW - Remineralization KW - BATS KW - ESTOC KW - North Atlantic SN - 0967-0645 TI - Oxygen dynamics in the North Atlantic subtropical gyre SP - 135 AV - none EP - 147 ER - TY - JOUR ID - soton348334 UR - https://eprints.soton.ac.uk/348334/ A1 - Cimatoribus, Andrea A. A1 - Drijfhout, Sybren S. A1 - Dijkstra, Henk A. Y1 - 2012/11// N2 - A box model of the inter-hemispheric Atlantic meridional overturning circulation is developed, including a variable pycnocline depth for the tropical and subtropical regions. The circulation is forced by winds over a periodic channel in the south and by freshwater forcing at the surface. The model is aimed at investigating the ocean feedbacks related to perturbations in freshwater forcing from the atmosphere, and to changes in freshwater transport in the ocean. These feedbacks are closely connected with the stability properties of the meridional overturning circulation, in particular in response to freshwater perturbations. A separate box is used for representing the region north of the Antarctic circumpolar current in the Atlantic sector. The density difference between this region and the north of the basin is then used for scaling the downwelling in the north. These choices are essential for reproducing the sensitivity of the meridional overturning circulation observed in general circulation models, and therefore suggest that the southernmost part of the Atlantic Ocean north of the Drake Passage is of fundamental importance for the stability of the meridional overturning circulation. With this configuration, the magnitude of the freshwater transport by the southern subtropical gyre strongly affects the response of the meridional overturning circulation to external forcing. The role of the freshwater transport by the overturning circulation (M ov ) as a stability indicator is discussed. It is investigated under which conditions its sign at the latitude of the southern tip of Africa can provide information on the existence of a second, permanently shut down, state of the overturning circulation in the box model. M ov will be an adequate indicator of the existence of multiple equilibria only if salt-advection feedback dominates over other processes in determining the response of the circulation to freshwater anomalies. M ov is a perfect indicator if feedbacks other than salt-advection are negligible. JF - Climate Dynamics KW - atlantic KW - meridional overturning circulation KW - stability KW - freshwater KW - salt-advection feedback KW - southern subtropical gyre SN - 0930-7575 TI - Meridional overturning circulation: stability and ocean feedbacks in a box model AV - none ER - TY - JOUR ID - soton340324 UR - https://eprints.soton.ac.uk/340324/ IS - 9-10 A1 - Cimatoribus, Andrea A. A1 - Drijfhout, Sybren S. A1 - den Toom, Matthijs A1 - Dijkstra, Henk A. Y1 - 2012/// N2 - The sensitivity of the Atlantic Meridional Overturning Circulation (AMOC) to changes in basin integrated net evaporation is highly dependent on the zonal salinity contrast at the southern border of the Atlantic. Biases in the freshwater budget strongly affect the stability of the AMOC in numerical models. The impact of these biases is investigated, by adding local anomaly patterns in the South Atlantic to the freshwater fluxes at the surface. These anomalies impact the freshwater and salt transport by the different components of the ocean circulation, in particular the basin-scale salt-advection feedback, completely changing the response of the AMOC to arbitrary perturbations. It is found that an appropriate dipole anomaly pattern at the southern border of the Atlantic Ocean can collapse the AMOC entirely even without a further hosing. The results suggest a new view on the stability of the AMOC, controlled by processes in the South Atlantic.
JF - Climate Dynamics VL - 39 KW - atlantic meridional overturning circulation KW - salinity KW - freshwater budget KW - salt-advection feedback KW - climate models KW - biases KW - permanent collapse KW - south atlantic SN - 0930-7575 TI - Sensitivity of the Atlantic meridional overturning circulation to South Atlantic freshwater anomalies SP - 2291 AV - public EP - 2306 ER - TY - JOUR ID - soton2018 UR - https://eprints.soton.ac.uk/2018/ IS - 2 A1 - Collins, M.A. A1 - Yau, C. A1 - Allcock, L. A1 - Thurston, M. Y1 - 2002/// JF - Bulletin of Marine Science VL - 71 KW - GEOGRAPHICAL DISTRIBUTION KW - BENTHOS KW - ATLANTIC OCEAN KW - SPECIES KW - TAXONOMY KW - BIOLOGY TI - Distribution of deep water benthic and bentho-pelagic cephalopods from the NE Atlantic SP - 1116 AV - none EP - 1117 ER - TY - JOUR ID - soton8871 UR - http://links.jstor.org/sici?sici=0024-3590%28200011%2945%3A7%3C1655%3AMAMIOS%3E2.0.CO%3B2-8 IS - 7 A1 - Comtet, T. A1 - Jollivet, D. A1 - Dixon, D.R. Y1 - 2000/// N2 - This paper describes the first successful attempt to trap and identify the larvae of a deep-sea vent organism using a combination of sediment traps and molecular analysis. During the European Union-funded MARVEL cruise in August and September 1997, sediment traps containing a high-salt DNA preservative were deployed around active black smoker chimneys on the newly discovered Rainbow vent field in an attempt to collect larval stages of the dominant vent bivalve Bathymodiolus azoricus. A total of 2,055 shelled mussel larvae was collected within a 2-week period, all of which were of identical size and shell morphology that indicated that they were at the settlement, prodissoconch II stage. Scanning electron microscopy of the shell hinge indicated that they belonged to the family Mytilidae, but it required molecular analysis to confirm their species identity. Polymerase chain reaction (PCR) amplification of the ITS2 region was performed on a subset of the larvae, and the resulting PCR products were cut with diagnostic restriction endonucleases to allow comparison with a DNA database based on adult specimens. The DNA restriction patterns typifying the Rainbow larvae were identical to those of adult B. azoricus from the Menez Gwen, Lucky Strike, and Rainbow vent sites and were significantly different from those that typified Bathymodiolus thermophilus (Pacific) and Bathymodiolus puteoserpentis (Snake Pit vent field on the Mid-Atlantic Ridge), which clearly points to the Rainbow larvae having their origin on that part of the ridge close to the Azores. These findings point to the value of sediment traps as a way to study the temporal and spatial aspects of larval settlement in deep-sea hydrothermal vent environments. JF - Limnology and Oceanography VL - 45 KW - MUSSELS KW - BIVALVIA KW - BIVALVES KW - MYTILIDAE KW - MID ATLANTIC RIDGE KW - IDENTIFICATION KW - HYDROTHERMAL COMMUNITIES SN - 0024-3590 TI - Molecular and morphological identification of settlement-stage vent mussel larvae, Bathymodiolus azoricus (Bivalvia: Mytilidae), preserved in situ at active vent fields on the Mid-Atlantic Ridge SP - 1655 AV - none EP - 1661 ER - TY - JOUR ID - soton44040 UR - https://eprints.soton.ac.uk/44040/ IS - 4 A1 - Copley, J.T.P. A1 - Jorgensen, P.B.K. A1 - Sohn, R.A. Y1 - 2007/08// N2 - This study presents a comparison of distribution and abundance of dominant megafaunal species at the TAG hydrothermal mound on the Mid-Atlantic Ridge from 1994 to 2004. A Geographical Information System (GIS) database was compiled from georeferenced observations of faunal abundances at 534 locations on the TAG hydrothermal mound, determined by image analysis of ROV dive footage from November 2004. These data are compared with observations from submersible dives in 1994 to assess changes in the extent and population density of aggregations of the shrimp Rimicaris exoculata at the central black smokers of TAG. The GIS database was also used to assess changes in abundance and distribution of the anemone Maractis rimicarivora by simulating the path of a biotransect conducted in 1994 and 1995. There was no evidence of a decline in the extent of shrimp aggregations at the central black smokers of TAG between 1994 and 2004. This result indicates that occasional exposure to high-intensity submersible lighting, which took place during several scientific expeditions in the intervening period, does not pose an immediate conservation threat to populations of R. exoculata. Similarly, there were no significant differences in the distribution and abundance of anemones between 1994 and 2004. These results indicate a constancy in the identity, distribution and abundance of dominant species at TAG that contrasts with other vent sites where quantitative time-series have been established. The reproductive pattern of R. exoculata was also examined by dissection and direct measurement of oocytes from females collected in September 1994 and November 2004, providing the first comparison of reproductive development in samples from different months for this species. There was no significant difference in oocyte size-frequency distributions of females collected in these samples, indicating a lack of seasonal reproduction in R. exoculata. JF - Journal of the Marine Biological Association of the United Kingdom VL - 87 KW - hydrothermal vents KW - ecology KW - temporal variation KW - mid-atlantic ridge SN - 0025-3154 TI - Assessment of decadal-scale ecological change at a deep Mid-Atlantic hydrothermal vent and reproductive time-series in the shrimp Rimicaris exoculata SP - 859 AV - public EP - 867 ER - TY - JOUR ID - soton445332 UR - https://eprints.soton.ac.uk/445332/ IS - 3-4 A1 - Copley, Jonathan T.P. A1 - Tyler, Paul A. A1 - Van Dover, Cindy L. A1 - Schultz, Adam A1 - Dickson, Penny A1 - Singh, Sandipa A1 - Sulanowska, Margaret Y1 - 1999/12/01/ N2 -

This paper evaluates the dynamics of two faunal assemblages colonizing high- and low-temperature habitats of the TAG hydrothermal mound on the Mid-Atlantic Ridge. Timelapse video and photographic transects were used to monitor changes in shrimp and anemone populations from June 1994 to March 1995. During this period, holes were drilled in the vicinity of the target populations by the Ocean Drilling Program (ODP). The a priori expectation of a rapid redistribution of motile alvinocaridid shrimp to occupy the optimal thermal and chemical habitat in response to changes in the pattern of hydrothermal activity was met by the observation of an increase in hydrothermal activity and shrimp population density at the site where a timelapse video system was deployed. The importance of hydrothermal activity as a control on the distribution of vent shrimp is suggested by tidal variations in the distribution of shrimp on a minidiffuser chimney. Sediment deposition during ODP drilling resulted in a temporary disturbance of the shrimp occupying the flat part of the mound surface seen by the timelapse video. In contrast to the changes observed in shrimp distribution, little change was observed in the distribution of anemones across the mound in two photographic transects 10 months apart, with the exception of a localized disturbance where anemones were buried by sediment around an ODP hole. Differences in the response of the shrimp and anemones to changes in the hydrothermal system may result from differences in their motility and rates of biological activity, or reflect a lower trophic position in the case of the shrimp.

JF - Marine Ecology VL - 20 KW - Hydrothermal vents KW - Mid-Atlantic Ridge KW - Rimicaris exoculata KW - Temporal variation SN - 0173-9565 TI - Subannual temporal variation in faunal distributions at the TAG hydrothermal mound (26°N, Mid-Atlantic Ridge) SP - 291 AV - none EP - 306 ER - TY - JOUR ID - soton344731 UR - https://eprints.soton.ac.uk/344731/ IS - 6 A1 - Coulson, T. A1 - Ezard, T.H.G. A1 - Pelletier, F. A1 - Tavecchia, G. A1 - Stenseth, N.C. A1 - Childs, D.Z. A1 - Pilkington, J.G. A1 - Pemberton, J.M. A1 - Kruuk, L.E.B. A1 - Clutton-Brock, T.H. A1 - Crawley, M.J. Y1 - 2008/// N2 - Two contrasting approaches to the analysis of population dynamics are currently popular: demographic approaches where the associations between demographic rates and statistics summarizing the population dynamics are identified; and time series approaches where the associations between population dynamics, population density, and environmental covariates are investigated. In this paper, we develop an approach to combine these methods and apply it to detailed data from Soay sheep (Ovis aries). We examine how density dependence and climate contribute to fluctuations in population size via age- and sex-specific demographic rates, and how fluctuations in demographic structure influence population dynamics. Density dependence contributes most, followed by climatic variation, age structure fluctuations and interactions between density and climate. We then simplify the density-dependent, stochastic, age-structured demographic model and derive a new phenomenological time series which captures the dynamics better than previously selected functions. The simple method we develop has potential to provide substantial insight into the relative contributions of population and individual-level processes to the dynamics of populations in stochastic environments.
JF - Ecology VL - 89 KW - age-structure fluctuations KW - nonlinear dynamics KW - north atlantic oscillation KW - ovis aries KW - soay sheep KW - time series analysis SN - 0012-9658 TI - Estimating the functional form for the density dependence from life history data SP - 1661 AV - none EP - 1674 ER - TY - CONF N1 - 2005 NERC Earth Observation Conference was part of: RSPSoc Annual Conference 'Measuring, Mapping and Managing a Hazardous World', Portsmouth University, UK, 6-9 Sept 2005. Abstract in book of abstracts (unpaginated) ID - soton17469 UR - https://eprints.soton.ac.uk/17469/ A1 - Cromwell, D. A1 - Houseago-Stokes, R.E. A1 - Shaw, A.G.P. A1 - Challenor, P.G. A1 - Tokmakian, R. Y1 - 2005/09/06/ N2 - We investigate the feasibility of measuring the meridional overturning circulation (MOC), i.e. the full-depth water mass transport, in the North Atlantic using satellite data. Using the Parallel Ocean Climate Model, we simulate satellite observations of ocean bottom pressure and sea surface height (SSH) over a 20-year period, and perform a linear regression on these variables to yield the MOC. As much as 93.5% of the variability in the smoothed transport is thereby explained. This increases to 98% when SSH and bottom pressure are first smoothed. We present initial studies of predicting the time evolution of the MOC, with promising results. KW - MOC KW - North Atlantic KW - Altimetry KW - Gravity KW - RAPID KW - GRACE TI - Towards measuring the meridional overturning circulation from space AV - none T2 - 2005 NERC Earth Observation Conference (06/09/05 - 06/09/05) ER - TY - RPRT ID - soton17527 UR - https://eprints.soton.ac.uk/17527/ A1 - Cunningham, S.A. Y1 - 2005/// N2 - The cruise report describes the acquisition and processing of transatlantic hydrographic, velocity, chemistry and other measurements made during three cruises in Spring 2004 at 24.5°N. Measurements were made from shallow water near Africa to shallow water just off Palm Springs beach on the eastern seaboard of the USA. During the principal cruise, RRS Discovery Cruise D279 (4 April to 10 May 2004), 125 full depth CTD and lowered acoustic Doppler current profiler (LADP) stations were completed between the USA and Africa and continuous underway observations were made of currents in the upper 1000m using a ship mounted 75kHz ADP and of surface salinity and temperature. At each station up to 24 water samples were captured for the analysis of oxygen, salinity, nitrate, silicate, phosphate, CFC11, 12, 113 and CCl4 (carbon tetrachloride), discrete total inorganic carbon (TCO2), discrete total alkalinity (TA) and, discrete partial pressure of CO2 (discrete pCO2). Direct, near real-time measurements were also made of the air-sea turbulent fluxes of momentum and sensible and latent heat in addition to various mean meteorological parameters including testing of a new Licor sensor to determine its suitability for making direct measurements of the air-sea CO2 flux. Atmospheric dust samples were gathered on a daily basis. Two prior cruises
D277 (26 February to 16 March) and D278 (19 to 30 March) completed 33 full depth CTD/LADP stations in the Florida and Deep Western Boundary Currents, including continuous underway observations of currents in the upper 1000m and of surface salinity and temperature. No LADP or chemistry measurements were made during these cruises. The three cruises provide one CTD and one CTD/LADP transect of the Florida Current, two Florida Current transects at 5knots with the shipboard ADP measuring to the bottom for high accuracy well resolved direct velocity measurements, one section of 16 CTD stations across the Deep Western Boundary Current and a 125 station transatlantic section with a full suite of physical and chemical measurements. The principal scientific objective is to estimate the circulation across 24.5°N, using for the first time, LADP profiles at each station as constraints in an inverse study. Using this circulation and the transatlantic distribution of temperature and other properties we will calculate Atlantic heat and property fluxes. We will also define the size and structure of the Atlantic Meridional Overturning Circulation (MOC) to compare to results from a recently deployed transatlantic mooring array designed to continuously measure the size and structure of the MOC. The 24.5°N section has now been occupied five times since 1957 (including the 2004 section reported here). Therefore, we will analyse temporal trends of temperature to see if the widely reported warming of the thermocline and intermediate waters and cooling of deep water is continuing. Carbon measurements were also obtained in 1992 and 1998 so this section provides a unique decadal view of anthropogenic carbon fluxes. PB - Southampton Oceanography Centre, University of Southampton T3 - 54 KW - ADCP KW - Atlantic Ocean KW - atmospheric chemistry KW - carbon tetrachloride KW - carbon KW - CFC KW - circulation KW - cruise D277 2004 KW - cruise D278 2004 KW - cruise D279 2004 KW - CTD KW - Discovery KW - Lowered ADCP KW - Meridional Overturning Circulation KW - meteorology KW - MOC KW - nutrients KW - Ocean Surveyor KW - oxygen KW - shipboard ADCP M1 - project_report TI - RRS "Discovery" Cruise D279, 04 Apr - 10 May 2004. A Transatlantic hydrography section at 24.5N AV - public EP - 199 ER - TY - JOUR ID - soton8729 UR - https://eprints.soton.ac.uk/8729/ IS - 1 A1 - Cunningham, S.A. Y1 - 2000/// N2 - A new formulation of the Bernoulli inverse is used to determine the circulation and flux of the North Atlantic from synoptic CTD observations. The inverse assumes that the compressible Bernoulli function, modified potential temperature and salinity are conserved on streamlines in steady, geostrophic, hydrostatic, mass and density conserving flow. Crossings between CTD stations in the distribution of modified potential temperature versus salinity define a set of streamlines. The Bernoulli function is conserved along streamlines and the difference in the Bernoulli function at each crossing is related to the contribution of the unknown sea-surface height (SSH) to the Bernoulli function. These crossings form a set of overdetermined simultaneous linear equations which we solve using a singular value decomposition. A covariance matrix of the SSH solution gives a good estimate of the SSH solution error. From the SSH we calculate a barotropic reference velocity which is added to the baroclinic velocity from the observed density distribution giving the total geostrophic velocity. The inverse is tested using output from the Ocean Circulation and Climate Advanced Model (OCCAM) where the SSH is known a priori: the mean SSH error is 2.2 cm, corresponding to a velocity error of ~1 cm/s for stations separated by 300 km. Inverses of the CTD data have a significantly smaller mean SSH error of 1.2 cm which corresponds to a velocity error of ~0.5 cm/s. Solutions are sensitive to the inclusion of deep crossings which result from observational error as a consequence of small meridional salinity gradients in North Atlantic Deep Water. The inverse is better than a classical dynamic height analysis of the data, by which we mean that the variance of the inverse circulation at depth is greater than the error variance. In the upper ocean (shallower than ?2 = 36.873 which is the top of the Labrador Sea Water) the North Atlantic Current and west wind drift transport 35 ± 4 Sv eastward between 39N and 54N. In the eastern North Atlantic the North Atlantic Current turns northward, west of 20W, with a flux of 14 ± 3 Sv into the Iceland Basin west of the Rockall-Hatton Plateau. The depth-integrated flux of the subpolar gyre in the Irminger Basin is 16 ± 6 Sv fed equally from sources in the western North Atlantic and from flow which crosses the Reykjanes Ridge east to west from the eastern North Atlantic. The circulation at the depth of the Labrador Sea Water is a mid-depth minimum and is generally dominated by error estimates. However, the flux west to east across the Mid-Atlantic Ridge is 3 ± 2 Sv. A simple estimate of the mean flushing time of the Labrador Sea Water layer in the eastern North Atlantic is ~16 years. At depth, over the Porcupine Abyssal Plain the inverse puts in place a basin scale cyclonic circulation and we note agreement with mean circulation rates of 1 to 2 cm/s derived from current meters. JF - Journal of Marine Research VL - 58 KW - WOCE KW - NORTH ATLANTIC OCEAN KW - OCEAN CIRCULATION KW - CTD OBSERVATIONS KW - BERNOULLI FUNCTION KW - OCEANOGRAPHIC DATA SN - 0022-2402 TI - Circulation and volume flux of the North Atlantic using synoptic hydrographic data in a Bernoulli inverse SP - 1 AV - none EP - 35 ER - TY - RPRT ID - soton295 UR - https://eprints.soton.ac.uk/295/ A1 - Cunningham, S.A. Y1 - 2000/// N2 - This report describes RRS Discovery cruise 242 from 07 September to 06 October 1999. The cruise title is Atlantic - Norwegian Exchanges. There are two distinct parts to this experiment with closely related objectives. The first is to measure the pathways and flux of warm, upper ocean water northward through the Iceland Basin and Rockall Trough to high latitudes. The second is to measure the returning flux of cold, deep water that flows through the Faroe Bank Channel into the North Atlantic. A full depth hydrographic section was occupied between Scotland and Iceland, repeating the frequently occupied Rockall Trough section (occupied 36 times between March 1975 and January 1996) and it's recent extension from Rockall to Iceland (occupied in 1997, 1998 and now in 1999). A second section was occupied from southeast Iceland to Lousy Bank (occupied in 1962,1990 and 1996). These two sections comprised CTD/LADCP stations with discrete vertical samples for salinity, oxygen, silicate, nitrate and phosphate. Horizontal station spacing was ~30 km in the Iceland Basin but much closer over steep bathymetry and in the Rockall Trough. Ancilliary measurements of transmittance and reversing temperature and salinity were also made. Shipbourne observations were made throughout the cruise and comprised ADCP, navigation, meteorology, waves, echosounding and surface temperature and salinity. These two sections were designed to measure the pathways of the northward flow through the Iceland Basin and Rockall Trough. Differences to earlier occupations will show the time variability of these flows. In the Faroe Bank Channel and on the Iceland Ridge eight sections were occupied (some repeats) to examine the cold outflow into the North Atlantic. These sections were made in the Faroe Bank Channel and downstream of the sill, at a horizontal separation of between 15 km and 40 km. Five of these were standard CTD/LADCP sections with chemistry observations. Three sections were also occupied using the BRIDGET deep tow vehicle. This vehicle carried a CTD and 12 bottle rosette for water samples as well as some auxiliary sensors. The key novelty was the mounting of self-contained downward and upward looking ADCP's. BRIDGET was towed at 100 m off bottom giving cross-stream measurements at high resolution of the velocity structure of the overflow. These sections were taken in and just downstream from the Faroe Bank Channel sill. We will examine the initial adjustment of the overflow and with contemporaneous observations made in the Faroe Shetland (Fisheries Research Services, Aberdeen) the role of hydraulic control at the Faroe Bank Channel sill. The two sections in the Iceland Basin cross the overflow 360 km and 660 km downstream from the source defining the far field location and properties of the overflow. A short section of XBT observations was made along the Wyville-Thomson Ridge to measure the temperature at two saddle points where it is occasionally observed that cold Faroe Bank Channel water passes into the Rockall Trough. PB - Southampton Oceanography Centre, University of Southampton T3 - 28 KW - Acoustic Doppler Current Profiler KW - BRIDGET mounted ADCP KW - BRIDGET KW - cruise 242 1999 KW - CTD observations KW - deep tow vehicle KW - Discovery KW - Faroe Bank Channel KW - flow through gaps KW - Iceland Basin KW - Iceland Ridge KW - lowered ADCP KW - North Atlantic KW - overflow KW - outflow KW - Rockall Trough KW - vessel mounted ADCP KW - water exchange KW - water masses KW - XBT M1 - project_report TI - RRS Discovery Cruise 242, 07 Sep-06 Oct 1999. Atlantic - Norwegian Exchanges AV - public EP - 128 ER - TY - JOUR ID - soton49680 UR - http://www.agu.org/journals/gl/gl0714/2007GL029821/ IS - 14 A1 - Cunningham, S.A. A1 - Alderson, S. Y1 - 2007/07// N2 - In 2004 a fifth occupation of a transatlantic section at 24.5°N allows us to examine decadal temperature and salinity changes using high quality full-depth hydrographic data since 1957. Waters shallower than 1750 dbar have been warming and salinifying at least since 1981 and in 2004 are significantly warmer and saltier than at any time since 1957, while deeper than 3000 dbar there has been continuous cooling and freshening since 1957. Temperature and salinity changes at constant pressures are partitioned into changes on isopycnal surfaces and changes due to the vertical movement of the isopycnals. Warming in the western Atlantic thermocline since 1957 at a rate of 0.0111 °C/yr dominates the transatlantic average, while deep water has cooled and freshened at rates of ?0.0021 °C/yr and ?0.0003 psu/yr respectively. We argue that the shallower and deeper changes are consistent with a recently reported increased southward thermocline circulation and reduced southward flux of deep water. JF - Geophysical Research Letters VL - 34 KW - Atlantic KW - temperature KW - salinity SN - 0094-8276 TI - Transatlantic temperature and salinity changes at 24.5°N from 1957 to 2004 AV - none ER - TY - RPRT N1 - New series incorporating reports from NOC Liverpool and Southampton Sites ID - soton208989 UR - https://eprints.soton.ac.uk/208989/ A1 - Cunningham, S.A. A1 - et al, Y1 - 2011/12// N2 - This cruise report covers scientific operations conducted during RRS Discovery Cruise D359. Cruise D359 departed from São Antonio, Cape Verde on Friday 17th December 2010 arriving Santa Cruz de Tenerife Friday 14th December 2011.

The purpose of the cruise was the refurbishment of an array of moorings on the mid-­Atlantic Ridge and off the Moroccan Coast at a nominal latitude of 26.5°N. The moorings are part of a purposeful Atlantic wide mooring array for monitoring the Atlantic Meridional Overturning Circulation and Heat Flux. The array is a joint UK/US programme and is known as the RAPID-­?WATCH/MOCHA array. Information and data from the project can be found on the web site hosted by the National Oceanography Centre Southampton http://www.noc.soton.ac.uk/rapidmoc and also from the British Oceanographic Data Centre http://www.bodc.ac.uk.

The RAPID transatlantic array consists of 24 moorings of which 21 are maintained by the UK, and 20 bottom landers of which 16 are maintained by the UK. The moorings are primarily instrumented with self logging instruments measuring conductivity, temperature and pressure. Direct measurements of currents are made in the shallow and deep western boundary currents. The bottom landers are instrumented with bottom pressure recorders (also known as tide gauges), measuring the weight of water above the instrument.

The RAPID naming convention for moorings is Western Boundary (WB), Eastern Boundary (EB) and Mid-­Atlantic Ridge (MAR) indicating the general sub-­regions of the array. Numbering increments from west to east. An L in the name indicates a bottom lander, M indicates a mini-­mooring with only one instrument, H indicates a mooring on the continental slope. During D359 we recovered: MAR0, MAR1L4, MAR1, MAR2, MAR3, MAR3L4, EB1, EB1L7, EBHi, EBH1, EBH1L7, EBH2, EBH3, EBH4, EBP2, EBH5, EBM5. We did not recover EBM1, EBM4, EBM6, EBH1 and MAR3. We deployed: MAR0, MAR1L7, MAR1, MAR2, MAR3, MAR3L6, EB1, EB1L7, EBHi, EBH1, EBH1L8, EBH2, EBH3, EBH4, EBP2, EBH5. A sediment trap mooring NOGST was also recovered and redeployed for the Ocean Biogeochemistry and Ecosystems Group at the NOCS.

CTD stations were conducted at convenient times throughout the cruise for purposes of providing pre and post deployment calibrations for mooring instrumentation and for testing mooring releases prior to deployment.

Shipboard underway measurements were systematically logged, processed and calibrated, including: waves (spectra of energy and significant wave height), surface meteorology (air pressure, temperature, wind speed and direction and radiation (total incident and photosynthetically active), 6m-­depth sea temperatures and salinities, water depth, navigation (differential GPS measurements feeding two independent and different receivers, heading, pitch and roll from a four antenna Ashtec ADU5 receiver, gyro heading and ships speed relative to the water using an electro-­magnetic log). Water velocity profiles from 15m to approximately 500m depth were obtained using a ship mounted 75 kHz acoustic Doppler current profiler. Sea-­water samples from CTD stations and of the sea-­surface were obtained for calibration and analysed on a salinometer referencing these samples against standard sea water. For velocity data (wind and currents) measured relative to the ship considerable effort was made to obtain the best possible earth-­referenced velocities.

Four APEX argo floats supplied by the Met Office were deployed at pre-­assigned locations, filling gaps in the network. PB - National Oceanography Centre T3 - 9 KW - RAPID KW - RAPID-­WATCH KW - MOCHA KW - moorings KW - landers KW - eastern boundary KW - mid-­Atlantic Ridge KW - western boundary KW - conductivity KW - temperature KW - pressure KW - velocity KW - bottompressure KW - tide gauges KW - current meters KW - Interocean S4 KW - Anderra RCM11 KW - Sea-Bird KW - microcat KW - SBE37 KW - SBE911 KW - SBE26 KW - SBE53 ED - Collins, J. M1 - project_report TI - RRS Discovery Cruise D359, 17 Dec 2010-14 Jan 2011. RAPID moorings cruise report AV - public EP - 197 ER - TY - RPRT N1 - New series incorporating reports from NOC Liverpool and Southampton Sites ID - soton190177 UR - https://eprints.soton.ac.uk/190177/ A1 - Cunningham, S.A. A1 - et al, Y1 - 2011/06// N2 - This cruise report covers scientific operations conducted during RV Oceanus OC459-1. Mooring
operations conducted on RV Ronald H. Brown RB10-09 are given as an Appendice. Cruise
OC459 departed from Woods Hole on 23rd March 2010 and arrived in Freeport, Grand Bahama on
04th April 2010.
The purpose of the cruise was the refurbishment of an array of moorings off the coast of Abaco
Island, Bahamas at a nominal latitude of 26.5°N. The moorings are part of a purposeful Atlantic
wide mooring array for monitoring the Atlantic Meridional Overturning Circulation and Heat
Flux. The array is a joint UK/US programme and is known as the RAPID-WATCH/MOCHA
array. Information and data from the project can be found on the web site hosted by the National
Oceanography Centre Southampton http://www.noc.soton.ac.uk/rapidmoc and also from the
British Oceanographic Data Centre http://www.bodc.ac.uk.
The RAPID transatlantic array consists of 24 moorings of which 21 are maintained by the UK,
and 17 bottom landers of which 15 are maintained by the UK. The moorings are primarily
instrumented with Sea-Bird self logging instruments measuring conductivity, temperature and
pressure. Direct measurements of currents are made in the shallow and deep western boundary
currents. The bottom landers are instrumented with bottom pressure recorders (also known as tide
gauges), measuring the weight of water above the instrument.
The RAPID naming convention for moorings is Western Boundary (WB), Eastern Boundary (EB)
and Mid-Atlantic Ridge (MAR) indicating the general sub-regions of the array. Numbering
increments from west to east. An L in the name indicates a bottom lander, M indicates a minimooring
with only one instrument, H indicates a mooring which is on the continental slope and is
instrumented over a limited depth range. During OC459-1 we recovered and redeployed: WB1,
WB2, WB6, WBH2, WBADCP, WB2L4 and WB4L4. WBAL1 was deployed on OC459-1.
Mooring WB4 was recovered and redeployed on RB10-09.
On OC459-1, CTD stations were conducted at convenient times throughout the cruise for purposes
of providing pre and post deployment calibrations for mooring instrumentation and for testing
mooring releases prior to deployment. Shipboard underway measurements were systematically
logged, processed and calibrated, including: waves (spectra of energy and significant wave
height), surface meteorology (air pressure, temperature, wind speed and direction and radiation
(total incident and photosynthetically active), sea temperatures and salinities, water depth and
navigation. Sea-water samples from CTD stations and of the sea-surface were obtained for
calibration. PB - National Oceanography Centre T3 - 1 KW - anderra RCM11 KW - bottom pressure KW - conductivity KW - current meters KW - eastern boundary KW - Interocean S4 KW - landers KW - microCAT KW - Mid-Atlantic Ridge KW - MOCHA KW - moorings KW - pressure KW - RAPIDWATCH KW - RAPID KW - SBE26 KW - SBE37 KW - SBE53 KW - SBE911 KW - Sea-Bird KW - temperature KW - tide gauges KW - velocity KW - western boundary ED - Collins, J. M1 - project_report TI - RV Oceanus Cruise CO459-1, 23 Mar-04 Oct 2010. RAPID Mooring Cruise Report AV - public EP - 101 ER - TY - RPRT ID - soton341283 UR - https://eprints.soton.ac.uk/341283/ A1 - Cunningham, S.A. A1 - et al, Y1 - 2012/07// N2 - This cruise report covers scientific operations conducted during RRS James Cook Cruise JC064. Cruise JC064, departed from Falmouth on Thursday 1st September 2011 arriving Santa Cruz de Tenerife Saturday 10th September to pick up extra members of the scientific party and arriving again in Santa Cruz on the 9th October. The purpose of the cruise was the refurbishment of an array of moorings on the mid-Atlantic Ridge and off the Moroccan Coast at a nominal latitude of 26.5°N. The moorings are part of a purposeful Atlantic wide mooring array for monitoring the Atlantic Meridional Overturning Circulation and Heat Flux. The array is a joint UK/US programme and is known as the RAPID-WATCH/MOCHA array. Information and data from the project can be found on the web site hosted by the National Oceanography Centre Southampton http://www.noc.soton.ac.uk/rapidmoc and also from the British Oceanographic Data Centre http://www.bodc.ac.uk.

The array as deployed in 2011-2012 consists of a total of 17 moorings, 16 landers and a single inverted echo sounder. The moorings are primarily instrumented with self logging instruments measuring conductivity, temperature and pressure. Direct measurements of currents are made in the shallow and deep western boundary currents. The bottom landers are instrumented with bottom pressure recorders (also known as tide gauges), measuring the weight of water above the instrument.

The RAPID naming convention for moorings is Western Boundary (WB), Eastern Boundary (EB) and Mid?Atlantic Ridge (MAR) indicating the general sub?regions of the array. Numbering increments from west to east. An L in the name indicates a bottom lander, M indicates a mini?mooring with only one instrument, H indicates a mooring on the continental slope. During JC064 we recovered: MAR0, MAR1L4, MAR1, MAR2, MAR3, MAR3L4, EB1, EB1L7, EBHi, EBH1, EBH1L7, EBH2, EBH3, EBH4, EBP2, EBH5, EBM5. We did not recover EBM1, EBM4, EBM6, EBH1 and MAR3. We deployed: MAR0, MAR1L7, MAR1, MAR2, MAR3, MAR3L6, EB1, EB1L7, EBHi, EBH1, EBH1L8, EBH2, EBH3, EBH4, EBP2, EBH5. A sediment trap mooring NOGST was also recovered and redeployed for the Ocean Biogeochemistry and Ecosystems Group at the NOCS.

CTD stations were conducted at convenient times throughout the cruise for purposes of providing pre and post deployment calibrations for mooring instrumentation and for testing mooring releases prior to deployment.

Shipboard underway measurements were systematically logged, processed and calibrated, including: waves (spectra of energy and significant wave height), surface meteorology (air pressure, temperature, wind speed and direction and radiation (total incident and photosynthetically active), 6m?depth sea temperatures and salinities, water depth, navigation (differential GPS measurements feeding two independent and different receivers, heading, pitch and roll, gyro heading and ships speed relative to the water using an electromagnetic log). Water velocity profiles from 15m to approximately 800m/300m depth were obtained using a ship mounted 75/150 kHz acoustic Doppler current profiler. Seawater samples from CTD stations and of the sea-surface were obtained for calibration and analysed on a salinometer referencing these samples against standard sea water. For velocity data (wind and currents) measured relative to the ship considerable effort was made to obtain the best possible earth referenced velocities.

Seven APEX argo floats supplied by the Met Office were deployed at preassigned locations, filling gaps in the network. PB - National Oceanography Centre T3 - 14 KW - RAPID KW - RAPID-­WATCH KW - MOCHA KW - moorings KW - landers KW - eastern boundary KW - mid-­Atlantic Ridge KW - western boundary KW - conductivity KW - temperature KW - pressure KW - velocity KW - bottompressure KW - tide gauges KW - current meters KW - Interocean S4 KW - Anderra RCM11 KW - Sea-Bird KW - microcat KW - SBE37 KW - SBE911 KW - SBE26 KW - SBE53 ED - McCarthy, G. ED - Collins, J. M1 - project_report TI - RRS James Cook Cruise JC064, 10 Sep - 09 Oct 2011. RAPID moorings cruise report AV - public EP - 183 ER - TY - RPRT ID - soton65412 UR - https://eprints.soton.ac.uk/65412/ A1 - Cunningham, S.A. Y1 - 2008/// N2 - This report describes the mooring operations and underway measurements conducted during RRS Discovery Cruise D324 conducted between 6th October 2007 and 9th November 2007. This cruise was completed as part of the United Kingdom Natural Environment Research Council (NERC) funded RAPID Programme to monitor the Atlantic Meridional Overturning Circulation at 26.5ºN. The primary purpose of this cruise was to service the Eastern Boundary and Mid-Atlantic ridge sections of the 26.5ºN mooring array. The array was first deployed in 2004 during RRS Discovery cruises D277 and D278 (SOC cruise report number 53), and serviced in 2005 during RRS Charles Darwin Cruise CD170 and RV Knorr Cruise KN182-2 (NOCS cruise report number 2), RRS Charles Darwin Cruise CD177 (NOCS cruise report number 5), in 2006 on RV Ronald H. Brown Cruise RB0602, RRS Discovery Cruise D304 (NOCS cruise report number 16) and FS Poseidon Cruises P343 and P345 (NOCS cruise report number 28), and in 2007 on RV Ronald H. Brown Cruise RB0701 (NOCS cruise report number 29). Cruise D324 had two legs with the first a transit from Falmouth, UK to Santa Cruz de Tenerife, Tenerife and the second sailing from, and returning to, Santa Cruz de Tenerife, Tenerife. The moorings serviced on this cruise were deployed on D304, P343 and P345, along with two landers deployed on CD170. The Rapid-MOC array of moorings was deployed across the Atlantic to set up a pre- operational prototype system to continuously observe the Atlantic Meridional Overturning Circulation (MOC). This array will be further refined and refurbished during subsequent years as part of the Rapid-WATCH programme. The instrumentation deployed on the array consists of a variety of CTD loggers, current meters, bottom pressure recorders, and Inverted Echo-sounders, which, combined with time series measurements of the Florida Current and wind stress estimates, can be used to determine the strength and structure of the MOC at 26.5ºN. PB - National Oceanography Centre T3 - 34 KW - Atlantic Ocean KW - bottom pressure recorder KW - BPR KW - D324 KW - CTD KW - current meter KW - RRS Discovery KW - Meridional Overturning Circulation KW - MOC KW - mooring array KW - Moorings KW - North Atlantic KW - RAPID KW - RAPIDMOC KW - Rapid-MOC KW - THC KW - thermohaline circulation ED - Rayner, D. M1 - project_report TI - RRS Discovery Cruise D324, 06 Oct-09 Nov 2007. RAPID Mooring Cruise Report AV - public EP - 141 ER - TY - RPRT ID - soton21035 UR - https://eprints.soton.ac.uk/21035/ A1 - Cunningham, S.A. A1 - Rayner, D. Y1 - 2006/// N2 - This report describes the mooring operations conducted during RRS Charles Darwin Cruise CD170 and RV Knorr Cruise KN182-2. Cruise CD170 was conducted between 2 April 2005 and 27 April 2005, and Cruise KN182-2 was conducted between 2 May 2005 and 26 May 2005.

These cruises were completed as part of the United Kingdom Natural Environment Research Council (NERC) funded RAPID Programme and the United States of America National Science Federation (NSF) funded MOCHA Programme to monitor the Atlantic Meridional Overturning Circulation at 26.5ºN. The primary purpose of these cruises was to service the 26.5ºN mooring array deployed in 2004 during RRS Discovery cruises D277 and D278 (cruise report number 53).

Cruise CD170 was from Tenerife to Bermuda, and covered the Eastern Boundary and Mid-Atlantic Ridge moorings deployed on D277. On arrival in Bermuda equipment and personnel were transferred to the RV Knorr, with Cruise KN182-2 covering the Western Boundary moorings deployed on Cruise D278. These cruises are the first annual refurbishment an array of moorings deployed across the Atlantic in order to set up a pre-operational
prototype system to continuously observe the Atlantic Meridional Overturning Circulation (MOC). This array will be further refined and refurbished during subsequent years.

The mooring array deployed in 2004 consisted of 19 moorings from the National Oceanography Centre, Southampton (NOC ? formerly the Southampton Oceanography Centre), with 3 from the Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami. The replacement array deployed in 2005 consisted of 24 NOC moorings, and 5 RSMAS moorings. Moorings are focused at the Eastern and Western
boundaries, along with a grouping at the Mid Atlantic Ridge.

The instruments deployed on the array consists of a variety of current meters, bottom pressure recorders and CTD loggers which, combined with time series measurements of the Florida Channel Current and wind stress estimates, will be used to determine the strength and structure of the MOC at 26.5ºN. PB - National Oceanography Centre T3 - 2 KW - Atlantic Ocean KW - bottom pressure recorder KW - BPR KW - cruise CD170 2005 KW - cruise KN182-2 2005 KW - CTD KW - current meter KW - Charles Darwin KW - Knorr KW - Meridional Overturning Circulation KW - MOC KW - mooring array KW - Moorings KW - North Atlantic KW - RAPID KW - RAPIDMOC KW - THC KW - thermohaline circulation M1 - project_report TI - RRS "Charles Darwin" Cruise CD170 and RV "Knorr" Cruise KN182-2. RAPID mooring cruise report April - May 2005 AV - public EP - 148 ER - TY - RPRT ID - soton41790 UR - https://eprints.soton.ac.uk/41790/ A1 - Cunningham, S.A. Y1 - 2006/// N2 - This report describes mooring operations and underway measurements conducted during RRS Charles Darwin Cruise CD177. Cruise CD177 was conducted between 12 November 2005 and 29 November 2005. The first part of the cruise consisted of a transit from Falmouth, UK to Santa Cruz de Tenerife, Tenerife with mooring preparation conducted on this leg. Further scientific staff joined in Santa Cruz de Tenerife for the second leg that started on the 19 November. The cruise finished in Tenerife on the 29 November.

This cruise was completed as part of the United Kingdom Natural Environment Research Council (NERC) funded RAPID Programme to monitor the Atlantic Meridional Overturning Circulation at 26.5ºN. The primary purposes of this cruise were to service the two key moorings (EB1 and EB2) on the eastern boundary of the 26.5ºN mooring array and to deploy two Pressure Inverted Echosounders (PIES). The array was first deployed in 2004 during RRS Discovery cruises D277 and D278 (Southampton Oceanography Centre Cruise Report No. 53) in order to set up a pre-operational prototype system to continuously observe the Atlantic Meridional Overturning Circulation (MOC). It was subsequently serviced on RRS Charles Darwin cruise CD170 and RV Knorr cruise KN182-2 (both covered in National Oceanography Centre Southampton Cruise Report No. 2). The array will be further refined and refurbished during subsequent years.

This cruise was planned in response to mooring losses suffered in the first year of the 26.5ºN array deployment. The two key eastern boundary moorings were subjected to damage through suspected fishing activity causing the loss of data above 1200m at the eastern boundary. To reduce the risk of data loss we plan to service the two key moorings on a six-monthly cycle.

Instruments deployed on the array consists of a variety of current meters, bottom pressure recorders and CTD loggers which, combined with time series measurements of the Florida Channel Current and wind stress estimates, will be used to determine the strength and structure of the MOC at 26.5ºN. (http://www.noc.soton.ac.uk/rapidmoc) PB - National Oceanography Centre T3 - 5 KW - Atlantic Ocean KW - bottom pressure recorder KW - BPR KW - cruise CD177 2005 KW - CTD KW - current meter KW - Charles Darwin KW - meridional overturning circulation KW - MOC KW - mooring array KW - moorings KW - North Atlantic KW - RAPID KW - RAPIDMOC KW - thermohaline circulation THC KW - McLane Moored Profiler KW - MMP KW - Pressure Inverted Echousounder KW - PIES ED - Rayner, D. M1 - project_report TI - RRS Charles Darwin Cruise CD177, 12-29 Nov 2005. RAPID Mooring Cruise Report AV - public EP - 50 ER - TY - RPRT ID - soton66655 UR - https://eprints.soton.ac.uk/66655/ A1 - Cunningham, S.A. Y1 - 2009/07// N2 - This report describes the mooring and underway operations conducted during RRS Discovery cruise D334 between 27 October and 24 November 2008. These mooring operations were completed as a part of the United Kingdom Natural Environment Research Council (NERC) funded RAPID Programme to monitor the Atlantic Meridional Overturning Circulation at 26.5°N. The primary purpose of this cruise was to service the Eastern Boundary and Mid-Atlantic Ridge sections of the 26.5°N mooring array first deployed during RRS Discovery cruises D277 and D278 (SOC cruise report number 53), and serviced in 2005 during RRS Charles Darwin cruise CD177 (NOCS cruise report number 5), in 2006 on RRS Discovery cruise D304 (NOCS cruise report number 16) and FS Poseidon cruises P343 and P345 (NOCS cruise report number 28) and in 2007 on RRS Discovery cruise D324 (NOCS cruise report number 34). Cruise D334 started and finished in Tenerife, Spain and covered the Eastern Boundary and Mid-Atlantic Ridge moorings deployed on D324 and P343. This cruise was the fourth annual refurbishment of the Eastern Boundary and Mid-Atlantic Ridge sections of the mooring array. The array will be further refined and refurbished during subsequent years. The instruments deployed consist of a variety of current meters, bottom pressure recorders, CTD loggers and Inverted Echosounders, which, combined with time series measurements of the Florida Straits current and wind stress estimates, will be used to determine the strength and structure of the MOC at 26.5°N. (http://www.noc.soton.ac.uk/rapidmoc) PB - National Oceanography Centre T3 - 38 KW - Atlantic Ocean KW - bottom pressure recorder KW - BPR KW - CTD KW - cruise D334 2008 KW - current meter KW - Discovery KW - North Atlantic KW - moorings KW - RAPID KW - RAPID-MOC KW - RAPID-WATCH KW - THC KW - thermohaline circulation KW - mooring array KW - MicroCAT KW - 26.5°N KW - MOC KW - meridional overturning circulation ED - Wright, P. M1 - project_report TI - RRS Discovery Cruise D334, 27 Oct-24 Nov 2008. RAPID Mooring Cruise Report AV - public EP - 189 ER - TY - RPRT N1 - 170pp & 55 logsheets ID - soton163915 UR - https://eprints.soton.ac.uk/163915/ A1 - Cunningham, S.A. A1 - et al, Y1 - 2010/// N2 - This cruise report covers RRS Discovery cruise D344. Cruise D344 was primarily used for the annual servicing of the eastern boundary and mid-Atlantic ridge moorings that form part of the RAPID-MOC mooring array across the North Atlantic at 26°N. In addition, the easternmost western boundary mooring, WB6, was serviced and the trial current meter mooring off the island of Abaco, WB-CM, was recovered. As the Discovery had made a faster passage than anticipated, a number of CTD stations were performed along 24° 30?N to augment the hydrography section scheduled to take place in January 2010.
The instruments deployed on the RAPID-MOC array consist of bottom pressure recorders, CTD loggers, and current meters which, combined with time series measurements of the Florida Channel Current, and wind stress estimates, will be used to determine the strength and structure of the MOC at 26.5°N.

(http://www.noc.soton.ac.uk/rapidmoc)
PB - National Oceanography Centre T3 - 51 KW - 26.5°N KW - Atlantic Ocean KW - bottom pressure recorder KW - BPR KW - cruise D344 KW - CTD KW - current meter KW - Discovery KW - Eastern Boundary KW - meridional overturning circulation KW - MicroCAT KW - Mid-AtlanticRidge KW - MOC KW - mooring array KW - Moorings KW - North Atlantic KW - RAPID-WATCH KW - RAPID KW - RAPIDMOC KW - THC KW - thermohaline circulation ED - Wright, P.G. M1 - project_report TI - RRS Discovery Cruise D344, 21 Oct-18 Nov 2009. RAPID Mooring Cruise Report. AV - public EP - 225 ER - TY - JOUR ID - soton361697 UR - https://eprints.soton.ac.uk/361697/ IS - 23 A1 - Cunningham, Stuart A. A1 - Roberts, Christopher D. A1 - Frajka-Williams, Eleanor A1 - Johns, William E. A1 - Hobbs, Will A1 - Palmer, Matthew D. A1 - Rayner, Darren A1 - Smeed, David A. A1 - McCarthy, Gerard Y1 - 2013/12/16/ N2 - Observations show that the upper 2 km of the subtropical North Atlantic Ocean cooled throughout 2010 and remained cold until at least December 2011. We show that these cold anomalies are partly driven by anomalous air-sea exchange during the cold winters of 2009/2010 and 2010/2011 and, more surprisingly, by extreme interannual variability in the ocean's northward heat transport at 26.5°N. This cooling driven by the ocean's meridional heat transport affects deeper layers isolated from the atmosphere on annual timescales and water that is entrained into the winter mixed layer thus lowering winter sea surface temperatures. Here we connect, for the first time, variability in the northward heat transport carried by the Atlantic Meridional Overturning Circulation to widespread sustained cooling of the subtropical North Atlantic, challenging the prevailing view that the ocean plays a passive role in the coupled ocean-atmosphere system on monthly-to-seasonal timescales. JF - Geophysical Research Letters VL - 40 KW - atlantic meridional overturning circulation KW - atlantic ocean heat transport KW - RAPID mooring array KW - atlantic subtropical gyre KW - ocean observing system KW - ocean heat content SN - 0094-8276 TI - Atlantic meridional overturning circulation slowdown cooled the subtropical ocean SP - 6202 AV - public EP - 6207 ER - TY - JOUR ID - soton184393 UR - https://eprints.soton.ac.uk/184393/ IS - 2 A1 - Cuvelier, Daphne A1 - Sarradin, Pierre-Marie A1 - Sarrazin, Jozée A1 - Colaço, Ana A1 - Copley, Jon T. A1 - Desbruyères, Daniel A1 - Glover, Adrian G. A1 - Santos, Ricardo Serrão A1 - Tyler, Paul A. Y1 - 2011/06// N2 - The Eiffel Tower edifice is situated in the Lucky Strike hydrothermal vent field at a mean depth of 1690 m on the Mid-Atlantic Ridge (MAR). At this 11-m-high hydrothermal structure, different faunal assemblages, varying in visibly dominant species (mussels and shrimp), in mussel size and in density of mussel coverage, were sampled biologically and chemically. Temperature and sulphide (?S) were measured on the different types of mussel-based assemblages and on a shrimp-dominated assemblage. Temperature was used as a proxy for calculating total concentrations of CH4. Based on the physico-chemical measurements, two microhabitats were identified, corresponding to (i) a more variable habitat featuring the greatest fluctuations in environmental variables and (ii) a second, more stable, habitat. The highest temperature variability and the highest maximum recorded temperatures were found in the assemblages visibly inhabited by alvinocaridid shrimp and dense mussel beds of large Bathymodiolus azoricus, whereas the less variable habitats were inhabited by smaller-sized mussels with increasing bare surface in between. Larger mussels appeared to consume more ?S compared with smaller-sized (<1 cm) individuals and thus had a greater influence on the local chemistry. In addition, the mussel size was shown to be significantly positively correlated to temperature and negatively to the richness of the associated macrofauna. The presence of microbial mats was not linked to specific environmental conditions, but had a negative effect on the presence and abundance of macro-fauna, notably gastropods. Whereas some taxa or species are found in only one of the two microhabitats, others, such as polychaetes and Mirocaris shrimp, cross the different microhabitats. Temperature was proposed to be a more limiting factor in species distribution than ?S. JF - Marine Ecology VL - 32 KW - Faunal assemblage KW - hydrothermal vent KW - microhabitat KW - Mid-Atlantic Ridge KW - physico-chemical characterisation SN - 0173-9565 TI - Hydrothermal faunal assemblages and habitat characterisation at the Eiffel Tower edifice (Lucky Strike, Mid-Atlantic Ridge) SP - 243 AV - none EP - 255 ER - TY - JOUR ID - soton69293 UR - https://eprints.soton.ac.uk/69293/ IS - 11 A1 - Cuvelier, Daphne A1 - Sarrazin, Jozée A1 - Colaço, Ana A1 - Copley, Jon A1 - Desbruyères, Daniel A1 - Glover, Adrian G. A1 - Tyler, Paul A1 - Serrão Santos, Ricardo Y1 - 2009/11// N2 - Whilst the fauna inhabiting hydrothermal vent structures in the Atlantic Ocean is reasonably well known, less is understood about the spatial distributions of the fauna in relation to abiotic and biotic factors. In this study, a major active hydrothermal edifice (Eiffel Tower, at 1690 m depth) on the Lucky Strike vent field (Mid-Atlantic Ridge (MAR)) was investigated. Video transects were carried out by ROV Victor 6000 and complete image coverage was acquired. Four distinct assemblages, ranging from dense larger-sized Bathymodiolus mussel beds to smaller-sized mussel clumps and alvinocaridid shrimps, and two types of substrata were defined based on high definition photographs and video imagery. To evaluate spatial variation, faunal distribution was mapped in three dimensions. A high degree of patchiness characterizes this 11 m high sulfide structure. The differences observed in assemblage and substratum distribution were related to habitat characteristics (fluid exits, depth and structure orientation). Gradients in community structure were observed, which coincided with an increasing distance from the fluid exits. A biological zonation model for the Eiffel Tower edifice was created in which faunal composition and distribution can be visually explained by the presence/absence of fluid exits.

JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 56 KW - Community structure KW - Spatial distribution KW - Faunal assemblages KW - Video analysis KW - Lucky Strike KW - Hydrothermal vent KW - Mid-Atlantic Ridge KW - Vent ecology SN - 0967-0637 TI - Distribution and spatial variation of hydrothermal faunal assemblages at Lucky Strike (Mid-Atlantic Ridge) revealed by high-resolution video image analysis SP - 2026 AV - none EP - 2040 ER - TY - JOUR ID - soton336228 UR - https://eprints.soton.ac.uk/336228/ IS - 3-4 A1 - Daley, Timothy J. A1 - Thomas, Elizabeth R. A1 - Holmes, Jonathan A. A1 - Street-Perrott, F. Alayne A1 - Chapman, Mark R. A1 - Tindall, Julia C. A1 - Valdes, Paul J. A1 - Loader, Neil J. A1 - Marshall, James D. A1 - Wolff, Eric W. A1 - Hopley, Philip J. A1 - Barber, Keith E. A1 - Atkinson, Tim A1 - Fisher, Elizabeth H. A1 - Robertson, Iain A1 - Hughes, Paul D.M. A1 - Roberts, C. Neil Y1 - 2011/12// N2 - An abrupt cold event ca. 8200 cal. yr BP, is believed to have been caused by the catastrophic release of ice-dammed meltwater from Lake Agassiz and associated disruption of the Atlantic Meridional Overturning Circulation (AMOC). Previous reviews have highlighted both the ?ideal? nature of the 8200 yr event as a target for numerical model validation and the likely geographical restriction of the ensuing cold event to the circum-North Atlantic region but have cited a lack of sufficiently resolved palaeoclimatic records to test this hypothesis. We review the current set of high-resolution stable isotope records from multiple archives (lake, bog, marine and ice cores) in the North Atlantic region for the period 9200?7400 yr BP (present = AD 1950). The isotopic values of terrestrial records are closely linked to isotopic values of palaeoprecipitation. All sites provided evidence for at least one centennial-scale anomaly (beginning ~ 8500?8250 yr BP) that exceeded background variability. No evidence for spatial or temporal transgression of the isotope anomalies was identified, implying that a simultaneous climate signal was observed in the circum-North Atlantic region. Comparison with new simulations using the UK Hadley Centre model HadCM3, which was isotope-enabled to simulate changes in the stable isotope composition of precipitation and forced by freshwater input (?hosing?) of 5 Sverdrups (Sv) (0.005 km3/s), for 1 yr, indicated agreement with the observed decrease in the amplitude of the isotope anomaly with distance from the NW North Atlantic. The model-simulated duration of the event, however, was consistently shorter than that observed in palaeoclimatic records. A review of evidence for forcing additional to the catastrophic release of meltwater from Lake Agassiz (solar variability, sea-ice feedback and longer-term meltwater history) suggested that reduced solar output did not directly coincide with the 8200 yr event, but that a more complex history of meltwater discharges and sea-ice feedback may have conditioned the AMOC for sustained climatic impact JF - Global and Planetary Change VL - 79 KW - 8200 KW - 8.2 ka BP event KW - palaeoclimate KW - stable water isotopes KW - data model comparison KW - north atlantic SN - 0921-8181 TI - The 8200yr BP cold event in stable isotope records from the North Atlantic region SP - 288 AV - restricted EP - 302 ER - TY - JOUR ID - soton386762 UR - https://eprints.soton.ac.uk/386762/ A1 - Danabasoglu, Gokhan A1 - Yeager, Steve G. A1 - Kim, Who M. A1 - Behrens, Erik A1 - Bentsen, Mats A1 - Bi, Daohua A1 - Biastoch, Arne A1 - Bleck, Rainer A1 - Böning, Claus A1 - Bozec, Alexandra A1 - Canuto, Vittorio M. A1 - Cassou, Christophe A1 - Chassignet, Eric A1 - Coward, Andrew C. A1 - Danilov, Sergey A1 - Diansky, Nikolay A1 - Drange, Helge A1 - Farneti, Riccardo A1 - Fernandez, Elodie A1 - Fogli, Pier Giuseppe A1 - Forget, Gael A1 - Fujii, Yosuke A1 - Griffies, Stephen M. A1 - Gusev, Anatoly A1 - Heimbach, Patrick A1 - Howard, Armando A1 - Ilicak, Mehmet A1 - Jung, Thomas A1 - Karspeck, Alicia R. A1 - Kelley, Maxwell A1 - Large, William G. A1 - Leboissetier, Anthony A1 - Lu, Jianhua A1 - Madec, Gurvan A1 - Marsland, Simon J. A1 - Masina, Simona A1 - Navarra, Antonio A1 - Nurser, A.J. George A1 - Pirani, Anna A1 - Romanou, Anastasia A1 - Salas y Mélia, David A1 - Samuels, Bonita L. A1 - Scheinert, Markus A1 - Sidorenko, Dmitry A1 - Sun, Shan A1 - Treguier, Anne-Marie A1 - Tsujino, Hiroyuki A1 - Uotila, Petteri A1 - Valcke, Sophie A1 - Voldoire, Aurore A1 - Wang, Qiang A1 - Yashayaev, Igor Y1 - 2016/01// N2 - Simulated inter-annual to decadal variability and trends in the North Atlantic for the 1958?2007 period from twenty global ocean ? sea-ice coupled models are presented. These simulations are performed as contributions to the second phase of the Coordinated Ocean-ice Reference Experiments (CORE-II). The study is Part II of our companion paper (Danabasoglu et al., 2014) which documented the mean states in the North Atlantic from the same models. A major focus of the present study is the representation of Atlantic meridional overturning circulation (AMOC) variability in the participating models. Relationships between AMOC variability and those of some other related variables, such as subpolar mixed layer depths, the North Atlantic Oscillation (NAO), and the Labrador Sea upper-ocean hydrographic properties, are also investigated. In general, AMOC variability shows three distinct stages. During the first stage that lasts until the mid- to late-1970s, AMOC is relatively steady, remaining lower than its long-term (1958?2007) mean. Thereafter, AMOC intensifies with maximum transports achieved in the mid- to late-1990s. This enhancement is then followed by a weakening trend until the end of our integration period. This sequence of low frequency AMOC variability is consistent with previous studies. Regarding strengthening of AMOC between about the mid-1970s and the mid-1990s, our results support a previously identified variability mechanism where AMOC intensification is connected to increased deep water formation in the subpolar North Atlantic, driven by NAO-related surface fluxes. The simulations tend to show general agreement in their temporal representations of, for example, AMOC, sea surface temperature (SST), and subpolar mixed layer depth variabilities. In particular, the observed variability of the North Atlantic SSTs is captured well by all models. These findings indicate that simulated variability and trends are primarily dictated by the atmospheric datasets which include the influence of ocean dynamics from nature superimposed onto anthropogenic effects. Despite these general agreements, there are many differences among the model solutions, particularly in the spatial structures of variability patterns. For example, the location of the maximum AMOC variability differs among the models between Northern and Southern Hemispheres. JF - Ocean Modelling VL - 97 KW - Global ocean ? sea-ice modelling KW - Ocean model comparisons KW - Atmospheric forcing KW - Inter-annual to decadal variability and mechanisms KW - Atlantic meridional overturning circulation variability KW - Variability in the North Atlantic SN - 1463-5003 TI - North Atlantic simulations in Coordinated Ocean-ice Reference Experiments phase II (CORE-II). Part II: Inter-annual to decadal variability SP - 65 AV - none EP - 90 ER - TY - JOUR ID - soton23989 UR - https://eprints.soton.ac.uk/23989/ IS - 6 A1 - Danelian, T. A1 - Le Callonnec, L. A1 - Erbacher, J. A1 - Mosher, D.C. A1 - Malone, M.C. A1 - Berti, D. A1 - Bice, K.L. A1 - Bostock, H. A1 - Brumsack, H.E. A1 - Forster, A. A1 - Heidersdorf, F. A1 - Henderiks, J. A1 - Janecek, T.J. A1 - Junium, C. A1 - MacLeod, K. A1 - Meyers, P.A. A1 - Mutterlose, J.H. A1 - Nishi, H. A1 - Norris, R.D. A1 - Ogg, J.G. A1 - O'Regan, M.A. A1 - Rea, B. A1 - Sexton, P. A1 - Sturt-Fredericks, H. A1 - Suganuma, Y. A1 - Thurow, J.W. A1 - Wilson, P.A. A1 - Wise, S.W. A1 - Glatz, C. N2 - Five sites located on a bathymetric transect of the distal Demerara Rise were studied by ODP Leg 207. Albian sediments of essentially terrigenous nature (clay, siltstone, sandstone) are the oldest drilled stratigraphic levels and form apparently the top of the synrift sequence. They are overlain by Cenomanian to Santonian finely laminated black shales, rich in organic matter of marine origin, which accumulated on a thermally subsiding ramp. Early Campanian hiatuses are thought to be the result of final disjunction of Demerara Rise (South America) from Africa and the onset of deep water communication between the two Atlantic basins (south and central). The overlying Uppermost Cretaceous?Oligocene chalk includes rich and diversified calcareous plankton assemblages, as well as two radiolarian-rich intervals (Late Campanian and Middle Eocene). A complex erosional surface developed during the Late Oligocene?Early Miocene. Sedimentation was impeded since then on the intermediate and deep sites of Demerara Rise, possibly due to the action of deep submarine currents. VL - 337 TI - Preliminary results on Cretaceous-Tertiary tropical Atlantic pelagic sedimentation (Demerara Rise, ODP Leg 207) AV - none EP - 616 N1 - In French, English abstract Y1 - 2005/// JF - Comptes Rendus Geoscience KW - Tropical Atlantic KW - Demerara KW - Cretaceous KW - Tertiary KW - black shales SN - 1631-0713 SP - 609 ER - TY - JOUR ID - soton429878 UR - https://eprints.soton.ac.uk/429878/ A1 - Davis, Clare E. A1 - Lohan, Maeve A1 - Tuerena, Robyn E. A1 - Cerdan Garcia, Elena A1 - Tagliabue, Alessandro A1 - Woodward, Malcolm A1 - Mahaffey, Claire Y1 - 2019/03/10/ N2 - Daily light?dark cycles drive the circadian rhythm of many ocean processes including photosynthesis, gene expression, and zooplankton diel vertical migration (DVM). In phosphate deplete surface ocean regions, microbes produce metalloenzymes, such as alkaline phosphatases (AP), to access dissolved organic phosphorus. Here, we provide novel evidence of diurnal variation in AP activity (APA) in the subtropical North Atlantic using two independent datasets, with APA being two? to three?fold higher at night. We demonstrate that zooplankton are a source of AP and postulate that zooplankton DVM is a source of enhanced AP in the surface waters at night, with reduction or degradation of AP during the day. Our results challenge the current assumption that APA is linear over a 24?h period. While future ocean scenarios predict intensification and expansion of oceanic phosphate limitation, our findings indicate a role for zooplankton in regenerating phosphate that is currently missing in conceptual and numerical models. JF - Limnology and Oceanography Letters KW - Alkaline Phosphatase KW - Zooplankton KW - North Atlantic TI - Diurnal variability in alkaline phosphatase activity and the potential role of zooplankton AV - public ER - TY - JOUR ID - soton41823 UR - https://eprints.soton.ac.uk/41823/ IS - 1-2 A1 - De Mol, B. A1 - Van Rensbergen, P. A1 - Pillen, S. A1 - Van Herreweghe, K. A1 - Van Rooij, D. A1 - McDonnell, A. A1 - Huvenne, V. A1 - Ivanov, M. A1 - Swennen, R. A1 - Henriet, J.P. Y1 - 2002/08/15/ N2 - The Porcupine Basin, southwest of Ireland, was one of the earliest sites from where the deep-water corals Lophelia sp. and Madrepora sp. were recovered. These deep-water corals have since been found all along the Atlantic margins of Europe, in water depths ranging from 50 to more than 2000 m. Recent geophysical studies have demonstrated the mound-building potential of deep-water corals. Available data indicate that three major provinces of coral bank occurrences can be identified in the Porcupine Basin: (1) high-relief surface mounds which have a dimension of 1 by 5 km and a height up to 200 m (?Hovland? mounds), flanked to the north by (2) a swarm of buried mounds, somewhat smaller (up to 90 m), and with more irregular shapes than those recognised in area 1 (?Magellan? mounds), and (3) outcropping or buried, conical mounds (single or in elongated clusters, up to 150 m high) occurring on the southeastern slope of the basin (?Belgica? mounds). As far as can be inferred from shallow cores, the surface lithology predominantly consists of an upper layer rich in foraminiferal sand and terrigenous silty clay with intercalations of biogenic rubble. The banks host a remarkable number of colonies of living and dead Lophelia pertusa and Madrepora oculata. The living and dead assemblages are underlain by a significant layer of coral debris in a muddy matrix. Deep-water coral debris together with a living association of the same species covers the surface of the ?Belgica? and ?Hovland? mounds, which may suggest that these corals have played a significant role in the development of the mound structures. The capacity for mound formation by scleractinian corals in the aphotic zone has been known for some time. Examples are found at different locations along the shelves and the continental margins of the North Atlantic. The role of the corals in these deep-water build-ups is still a point of debate. Though the genesis and initial control of mound settings in this basin might be related to hydrocarbon seeps, it appears that the major development of the Porcupine coral banks in recent geological times has most likely been controlled by oceanic circulation and dynamics in water masses and nutrient supply. JF - Marine Geology VL - 188 KW - coral banks KW - Mediterranean outflow water KW - deep-water corals KW - Porcupine Basin KW - NE Atlantic SN - 0025-3227 TI - Large deep-water coral banks in the Porcupine Basin, southwest of Ireland SP - 193 AV - none EP - 231 ER - TY - GEN N1 - Funding Information: This review is a result of the project ISLANDPALECO that has received funding from the European Union?s Horizon 2020 research and innovation programme under the Marie Sk?odowska-Curie grant agreement No 700952 and supported L.d.N. participation. Publisher Copyright: © 2020 Elsevier Ltd ID - soton442065 UR - https://eprints.soton.ac.uk/442065/ A1 - De Nascimento, Lea A1 - Nogué, Sandra A1 - Naranjo-Cigala, Agustín A1 - Criado, Constantino A1 - Mcglone, Matt A1 - Fernández-Palacios, Enrique A1 - Fernández-Palacios, José María Y1 - 2020/07/01/ N2 - Oceanic islands remained free of humans until relatively recent times. On contact, humans encountered pristine environments with unique ecosystems and species highly vulnerable to novel impacts. In the course of rendering an island habitable, the new settlers transformed it through fire, deforestation, hunting and introduction of pests and weeds. The result, as described for many oceanic islands globally, has been a catastrophe for biodiversity. Here we present the case of the Canary Islands, an Atlantic archipelago renowned for its exceptional biodiversity, and show that these islands have been no exception to the general rule. We review the archaeological, palaeoecological, palaeontological and ecological literature for the archipelago and discuss the ecological consequences ? in particular habitat transformation and biodiversity loss ? of human settlement. In contrast to previous views that prehistoric humans had only limited impacts on these islands, we show that vegetation change, increased fire, soil erosion, species introductions and extinctions follow the familiar oceanic pattern. Timing of human settlement of the Canary Islands has been controversial, with revised archaeological dates suggesting a relatively late arrival at the beginning of the Common Era, while palaeoecological and palaeontological evidence favours a presence several centuries earlier. While the matter is still not settled, we suggest that settlement sometime between 2400 and 2000 cal years BP is a possibility. KW - Extinction KW - Holocene KW - Introduced species KW - North Atlantic KW - Oceanic islands KW - Paleogeography KW - Prehistoric human impact KW - Vegetation dynamics SN - 0277-3791 TI - Human impact and ecological changes during prehistoric settlement on the Canary Islands AV - public ER - TY - JOUR ID - soton8890 UR - https://eprints.soton.ac.uk/8890/ A1 - De Vries, P. A1 - Drijfhout, S.S. A1 - Coward, A.C. Y1 - 2000/// JF - International WOCE Newsletter VL - No.39 KW - WOCE KW - NORTH ATLANTIC KW - OCCAM KW - UPWELLING KW - DEEP WATER TI - The role of the Southern Ocean in the upwelling of North Atlantic Deep Water SP - 12 AV - none EP - 15 ER - TY - JOUR ID - soton6060 UR - https://eprints.soton.ac.uk/6060/ IS - 47, Supplement A1 - Dean, S.M. A1 - Fliedner, M.M. A1 - Henstock, T.J. A1 - Minshull, T.A. A1 - Murton, B.J. A1 - White, R.S. Y1 - 2001/// JF - EOS: Transactions American Geophysical Union VL - 82 KW - NUMERICAL MODELS KW - CONTINENTAL MARGINS KW - NORTH ATLANTIC OCEAN KW - GEOCHEMICAL DATA SN - 0096-3941 TI - Numerical modelling of rift-related magmatism and melt chemistry at passive margins (abstract of poster presented at AGU Fall Meeting, San Francisco, CA, 10-14 Dec 2001) AV - none ER - TY - JOUR ID - soton372102 UR - https://eprints.soton.ac.uk/372102/ IS - 22 A1 - Desbruyères, D.G. A1 - McDonagh, E.L. A1 - King, B.A. A1 - Garry, F.K. A1 - Blaker, A.T. A1 - Moat, B. A1 - Mercier, H. Y1 - 2014/11// N2 - The vertical structure of temperature trends in the northeastern Atlantic (NEA) is investigated from a blend of Argo and hydrography data. The representativeness of sparse hydrography sampling in the basin-mean is assessed using a numerical model. Between 2003 and 2013, the NEA underwent a strong surface cooling (0-450?m) and a significant warming at intermediate and deep levels (1000?m-3000?m) that followed a strong cooling trend observed between 1988 and 2003. During 2003-2013, gyre-specific changes are found in the upper 1000?m (warming and cooling of the subtropical and subpolar gyres, respectively) whilst the intermediate and deep warming primarily occurred in the subpolar gyre, with important contributions from isopycnal heave and water mass property changes. The full-depth temperature change requires a local downward heat flux of 0.53?±?0.06?W?m?2 through the sea-surface, and its vertical distribution highlights the likely important role of the NEA in the recent global warming hiatus. JF - Geophysical Research Letters VL - 41 KW - North Atlantic KW - temperature KW - observations KW - hiatus SN - 0094-8276 TI - Full-depth temperature trends in the Northeastern Atlantic through the early 21st century SP - 7971 AV - public EP - 7979 ER - TY - JOUR ID - soton23988 UR - https://eprints.soton.ac.uk/23988/ IS - 1 A1 - Dietze, H. A1 - Oschlies, A. Y1 - 2005/// N2 - Apparent oxygen utilisation is potentially biased by abiotic, physical processes. Using a coupled 3-D circulation-oxygen model, this potential is quantitatively estimated for a region in the eastern subtropical North Atlantic, called the Beta Triangle, where an inconsistency exists between observational estimates of high carbon export from the euphotic zone, based on oxygen utilisation rates in the thermocline (Jenkins 1982), and those of low nutrient supply to the euphotic zone (Lewis et al. 1986, 2004). Our results indicate that in the upper ocean, the Jenkins (1982) estimate is indeed biased high by approximately 10% due to abiotic processes feigning respiration, thus contributing to the apparent inconsistency. Vertical integration, however, yields an abiotic fraction of less than 3%, so the apparent observational discrepancy can not be resolved. JF - Ocean Dynamics VL - 55 KW - apparent oxygen utilisation KW - Subtropical North Atlantic KW - carbon export KW - euphotic zone SN - 1616-7341 TI - Modeling abiotic production of apparent oxygen utilisation in the oligotrophic subtropical North Atlantic SP - 28 AV - none EP - 33 ER - TY - JOUR ID - soton18799 UR - http://www.agu.org/journals/jc/jc0509/2004JC002453/ IS - C9 A1 - Dietze, H. A1 - Oschlies, A. Y1 - 2005/// N2 - The assumption that abiotic air-sea gas exchange is, via the temperature dependence of the gas' solubility, proportional to the surface heat flux is often used to distinguish between physically and biotically inferred oxygen fluxes across the sea surface. We quantitatively investigate its validity in the context of an eddy-permitting circulation model that contains an abiotic oxygen compartment. In the model, the ?true? abiotic oxygen air-sea fluxes are systematically lower than those predicted by the air-sea heat flux relation. This discrepancy is caused by the nonlinear relationship between temperature and solubility that results in the saturation of a mixed water parcel being higher than the arithmetic mean saturation of the mixed components. This effect results in a simulated additional sea-to-air oxygen flux of about 0.5 mol O2 m-2 a-1 north of 40°N, which is not accounted for by the heat-flux relation and which is of similar magnitude as, though at the lower end of, biotically induced oxygen fluxes. Simulated outgassing of the model's abiotic oxygen is also higher than that predicted by the heat-flux relation at the equator (by ?0.25 mol O2 m-2 a-1), where numerical artifacts endemic to state-of-the-art z level ocean models are found to affect simulated air-sea gas exchange. In addition to discrepancies in the annual mean fluxes, model results also indicate that the subtropical seasonal cycle in abiotic air-sea oxygen exchange is smaller by approximately 20% than the estimate based on air-sea heat fluxes, a result consistent with admittedly sparse observations of argon saturation. JF - Journal of Geophysical Research: Oceans VL - 110 KW - modeling air-sea oxygen flux KW - North Atlantic KW - mixing TI - On the correlation between air-sea heat flux and abiotically induced oxygen gas exchange in a circulation model of the North Atlantic AV - none ER - TY - JOUR ID - soton58356 UR - https://eprints.soton.ac.uk/58356/ IS - 7 A1 - Dimmer, C.H. A1 - McCulloch, A. A1 - Simmonds, P.G. A1 - Nickless, G. A1 - Bassford, M.R. A1 - Smythe-Wright, D. Y1 - 2001/// N2 - A fully automated twin ECD gas chromatograph system with sample enriching adsorption?desorption primary stage was deployed on two field campaigns ? Ny-Ålesund, Svalbard, Arctic Norway (July?September 1997), and the RRS Discovery CHAOS cruise of the northeast Atlantic (April?May 1998). Concentrations of an extensive set of halocarbons were detected at hourly intervals at pptv levels. We present here the results obtained for the chlorinated solvents, tetrachloroethene (PCE) and trichloroethene (TCE). Average baseline PCE and TCE concentrations of 1.77 and 0.12 pptv, respectively, were recorded in Ny-Ålesund. During pollution incidences, concentrations rose to 5.61 (PCE) and 3.18 pptv (TCE). The cruise data showed average concentrations ranging from 4.26 (PCE) and 1.66 pptv (TCE) for air masses originating over the North Atlantic and Arctic open oceans, to maxima of 15.59 (PCE) and 17.51 pptv (TCE) for polluted air masses from Northern Europe. The data sets emphasise the difficulties in defining remote sites for background tropospheric halocarbon measurements, as Ny-Ålesund research station proved to be a source of tetrachloroethene. The data also suggest possible oceanic emissions of trichloroethene in the sub-tropical ocean. JF - Atmospheric Environment VL - 35 KW - Tetrachloroethene KW - Trichloroethene KW - Arctic troposphere KW - Emissions KW - Svalbard KW - Atlantic SN - 1352-2310 TI - Tropospheric concentrations of the chlorinated solvents, tetrachloroethene, and trichloroethene, measured in the remote Northern Hemisphere SP - 1171 AV - none EP - 1182 ER - TY - JOUR ID - soton6119 UR - https://eprints.soton.ac.uk/6119/ IS - 2 A1 - Dixon, D.R. A1 - Dando, P.R. A1 - Santos, R.S. A1 - Gwynn, J.P. A1 - Ventox, Consortium Y1 - 2001/// JF - InterRidge News VL - 10 KW - HYDROTHERMAL VENTS KW - MUSSELS KW - MID ATLANTIC RIDGE KW - CAGES KW - BIOLOGY TI - Retrievable cages open up new era in deep-sea vent research SP - 21 AV - none EP - 26 ER - TY - JOUR ID - soton6139 UR - https://eprints.soton.ac.uk/6139/ IS - 1 A1 - Dixon, D.R. A1 - Sarradin, P.M. A1 - Dixon, L.R.J. A1 - Khripounoff, A. A1 - Colaco, A. A1 - Santos, R.S. Y1 - 2002/// JF - InterRidge News VL - 11 KW - MUSSELS KW - MID ATLANTIC RIDGE KW - REPRODUCTION KW - SEASONALITY KW - MYTILIDAE KW - SEDIMENT TRAPS KW - BIOLOGY TI - Towards unravelling the enigma of vent mussel reproduction on the Mid Atlantic Ridge, or when ATOS met CagesNF 0 SP - 14 AV - none EP - 17 ER - TY - JOUR ID - soton379601 UR - https://eprints.soton.ac.uk/379601/ IS - 7 A1 - Dmitrenko, Igor A. A1 - Rudels, Bert A1 - Kirillov, Sergey A. A1 - Aksenov, Yevgeny O. A1 - Lien, Vidar S. A1 - Ivanov, Vladimir V. A1 - Schauer, Ursula A1 - Polyakov, Igor V. A1 - Coward, Andrew A1 - Barber, David G. Y1 - 2015/07// N2 - The Atlantic Water flow from the Barents and Kara seas to the Arctic Ocean through the St. Anna Trough (SAT) is conditioned by interaction between Fram Strait branch water circulating in the SAT and Barents Sea branch water?both of Atlantic origin. Here we present data from an oceanographic mooring deployed on the eastern flank of the SAT from September 2009 to September 2010 as well as CTD (conductivity-temperature-depth) sections across the SAT. A distinct vertical density front over the SAT eastern slope deeper than ?50 m is attributed to the outflow of Barents Sea branch water to the Arctic Ocean. In turn, the Barents Sea branch water flow to the Arctic Ocean is conditioned by two water masses defined by relative low and high fractions of the Atlantic Water. They are also traceable in the Nansen Basin downstream of the SAT entrance. A persistent northward current was recorded in the subsurface layer along the SAT eastern slope with a mean velocity of 18 cm s?1 at 134?218 m and 23 cm s?1 at 376?468 m. Observations and modeling suggest that the SAT flow has a significant density-driven component. It is therefore expected to respond to changes in the cross-trough density gradient conditioned by interaction between the Fram Strait and Barents Sea branches. Further modeling efforts are necessary to investigate hydrodynamic instability and eddy generation caused by the interaction between the SAT flow and the Arctic Ocean Fram Strait branch water boundary current. JF - Journal of Geophysical Research: Oceans VL - 120 KW - Atlantic Water KW - Fram Strait branch water flow KW - Barents Sea branch water flow KW - mooring observations KW - St. Anna Trough SN - 2169-9275 TI - Atlantic water flow into the Arctic Ocean through the St. Anna Trough in the northern Kara Sea SP - 5158 AV - public EP - 5178 ER - TY - JOUR ID - soton337007 UR - https://eprints.soton.ac.uk/337007/ IS - 1 A1 - Donald, Kirsten M. A1 - Preston, Joanne A1 - Williams, Suzanne T. A1 - Reid, David G. A1 - Winter, David A1 - Alvarez, Raquel A1 - Buge, Barbara A1 - Hawkins, Stephen J. A1 - Templado, Jose A1 - Spencer, Hamish G. Y1 - 2012/// N2 - Snails in the closely related trochid genera Phorcus Risso, 1826 and Osilinus Philippi, 1847 are ecologically important algal grazers in the intertidal zone of the northeastern Atlantic Ocean and Mediterranean Sea. Here we present the first complete molecular phylogeny for these genera, based on the nuclear 28S rRNA gene and the mitochondrial 16S rRNA and COI genes, and show that the current classification is erroneous. We recognize nine species in a single genus, Phorcus: estimated by BEAST analysis, this arose 30 (±10) Ma; it consists of two subgenera, Phorcus and Osilinus, which we estimate diverged 14 (±4.5) Ma. Osilinus kotschyi, from the Arabian and Red Seas, is not closely related and is tentatively referred to Priotrochus Fischer, 1879. Our phylogeny allows us to address biogeographical questions concerning the origins of the Mediterranean and Macaronesian species of this group. The former appear to have evolved from Atlantic ancestors that invaded the Mediterranean on several occasions after the Zanclean Flood, which ended the Messinian Salinity Crisis 5.3 Ma; whereas the latter arose from several colonizations of mainland Atlantic ancestors within the last 3 (±1.5) Ma. JF - Molecular Phylogenetics and Evolution VL - 62 KW - Atlantic KW - Dispersal KW - Mediterranean KW - Osilinus KW - Phorcus KW - Priotrochus KW - Tethyan realm SN - 1055-7903 TI - Phylogenetic relationships elucidate colonization patterns in the intertidal grazers Osilinus Philippi, 1847 and Phorcus Risso, 1826 (Gastropoda: Trochidae) in the northeastern Atlantic Ocean and Mediterranean Sea SP - 35 AV - restricted EP - 45 ER - TY - JOUR ID - soton67257 UR - https://eprints.soton.ac.uk/67257/ IS - 3-4 A1 - Dorschel, B. A1 - Wheeler, A.J. A1 - Huvenne, V.A.I. A1 - de Haas, H. Y1 - 2009/08/15/ N2 - Cold-water coral mounds are common features in certain regions along the Atlantic margin. They occur in mound provinces in various settings, characterised by specific environmental conditions that steer and influence coral mound initiation, growth and demise (e.g. bottom current intensity, sediment input and food supply). In order to add detail to the diversity of environmental conditions described in relation to these structures, this study investigates mounds in a generally erosive setting on the northwest Porcupine Bank (NE Atlantic)?in contrast to previous studies in less hydrodynamically active settings.
TOBI (Towed Ocean Bottom Instrument) side-scan sonar data revealed abundant erosive features in the study area. They occur in the form of erosional scarps, erosional pits and locally scoured seabed. Furthermore, two large (several hundred metres high) and 101 small (tens of metres high) cold-water coral mounds were identified on the TOBI images. Most of the mounds are located on top of erosional scarps pointing to the cold-water corals' preference for areas with enhanced current intensities. Within the study area, a general trend of northward decreasing mound heights and increasing abundance of erosive features can be observed.
High-resolution ROV (Remotely Operated Vehicle) video observations at four sites within the TOBI coverage illustrate that only the southernmost mound shows signs of active mound growth while the other mounds represent relict structures with limited coral cover opportunistically taking advantage of available hard substrate in the form of consolidated/lithified sediments. The distribution of erosion features, seabed features and seabed facies on the northwest Porcupine Bank indicates an environmental window in which the interplay of coral growth, sediment input and sediment preservation leads to the formation of mound sediments and therefore mound growth. Whereas too weak bottom currents do not support thriving coral thickets, too strong bottom currents hamper any deposition and, thus, mound growth. As this environmental window varies over time, mound sizes on the Porcupine Bank (and probably also in other mound settings) most likely reflect the duration in time of such an environmental window of optimal growth conditions around a given mound, rather than an indication of the overall age of the mound.
JF - Marine Geology VL - 264 KW - cold-water coral mound KW - erosion KW - environmental window KW - coral facies KW - iceberg ploughmarks KW - side-scan sonar KW - remotely operated vehicle KW - Porcupine Bank KW - NE Atlantic SN - 0025-3227 TI - Cold-water coral mounds in an erosive environmental setting: TOBI side-scan sonar data and ROV video footage from the northwest Porcupine Bank, NE Atlantic SP - 218 AV - none EP - 229 ER - TY - JOUR ID - soton348366 UR - https://eprints.soton.ac.uk/348366/ IS - 4 A1 - Drijfhout, Sybren A1 - Hazeleger, Wilco A1 - Selten, Frank A1 - Haarsma, Rein Y1 - 2008/// N2 - The response of the internal variability of the Atlantic Meridional Overturning Circulation (MOC) to enhanced atmospheric greenhouse gas concentrations has been estimated from an ensemble of climate change scenario runs. In the model, enhanced greenhouse forcing results in a weaker and shallower MOC with reduced internal variability. At the same time at 55 degrees N between 0 and 1,000 m the overturning increases as a result of a change in the area of convection. In a warmer world, new regions of deepwater formation form further north due to the poleward retreat of the sea-ice boundary. The dominant pattern of internal MOC-variability consists of a monopole centered around 35 degrees N. Due to anthropogenic warming this monopole shifts poleward. The shift is associated with a stronger relation between MOC-variations and heat flux variations over the subpolar gyre. In old convective sites (Labrador Sea) convection becomes more irregular which leads to enhanced heat flux variability. In new convective sites heat flux variations initially are related to sea-ice variations. When the sea-ice coverage further decreases they become associated with (irregular) deepwater formation. Both processes act to tighten the relation between subpolar surface heat flux variability and MOC-variability, resulting in a poleward shift of the latter. JF - Climate Dynamics VL - 30 KW - meridional overturning cell KW - north atlantic KW - subpolar gyre KW - climate change SN - 0930-7575 TI - Future changes in internal variability of the Atlantic Meridional Overturning Circulation SP - 407 AV - none EP - 419 ER - TY - JOUR ID - soton365713 UR - https://eprints.soton.ac.uk/365713/ IS - 17 A1 - Duchez, A. A1 - Hirschi, J.J.-M. A1 - Blaker, A.T. A1 - Bryden, H.L. A1 - de Cuevas, B. A1 - Atkinson, C.P. A1 - McCarthy, G.D. A1 - Frajka-Williams, E. A1 - Rayner, D. A1 - Smeed, D. A1 - Cunningham, S.A. A1 - Mizielinski, M.S. Y1 - 2014/09/01/ N2 - The Atlantic Meridional Overturning Circulation (AMOC) has received considerable attention, motivated by its major role in the global climate system. Observations of AMOC strength at 26°N made by RAPID-WATCH, provide our best current estimate of the state of the AMOC. The period 2004-2011 when RAPID AMOC is available is too short to assess decadal variability of the AMOC. In this modelling study, we define a new AMOC index (called AMOCSV ) at 26°N that combines the Florida Straits transport, the Ekman transport and the southward geostrophic Sverdrup transport. Our main hypothesis in this study is that the Upper Mid-Ocean geostrophic transport calculated using the RAPID array, is also wind-driven and can be approximated by the geostrophic Sverdrup transport at interannual and longer timescales. This index is expected to reflect variations in the AMOC at interannual / decadal time scales. This estimate of the surface branch of the AMOC can be constructed as long as reliable measurements are available for the Gulf Stream and for wind stress. To test the reliability of the AMOCSV on interannual and longer timescales, two different NEMO simulations are used: a forced and a coupled simulation. Using these simulations the AMOCSV captures a substantial fraction of the AMOC variability and is in good agreement with the AMOC transport at 26°N on both interannual and decadal timescales. These results indicate that it might be possible to extend the observation-based AMOC at 26°N back to the 1980s. JF - Journal of Climate VL - 27 KW - North Atlantic Ocean KW - Meridional overturning circulation KW - Climate change KW - Ocean models KW - Interannual variability KW - Multidecadal variability SN - 0894-8755 TI - A new index for the Atlantic Meridional Overturning Circulation at 26°N SP - 6439 AV - public EP - 6455 ER - TY - JOUR ID - soton384496 UR - https://eprints.soton.ac.uk/384496/ IS - 9 A1 - Duchez, Aurélie A1 - Courtois, Peggy A1 - Harris, Elizabeth A1 - Josey, Simon A1 - Kanzow, Torsten A1 - Marsh, Robert A1 - Smeed, David A1 - Hirschi, Joël Jean-Marie Y1 - 2016/05// N2 - The Atlantic meridional overturning circulation (AMOC) plays a critical role in the climate system and is responsible for much of the meridional heat transported by the ocean. In this paper, the potential of using AMOC observations from the 26 ? N RAPID array to predict North Atlantic sea surface temperatures is investigated for the first time. Using spatial correlations and a composite method, the AMOC anomaly is used as a precursor of North Atlantic sea-surface temperature anomalies (SSTAs). The results show that the AMOC leads a dipolar SSTA with maximum correlations between 2 and 5 months. The physical mechanism explaining the link between AMOC and SSTA is described as a seesaw mechanism where a strong AMOC anomaly increases the amount of heat advected north of 26 ? N as well as the SSTA, and decreases the heat content and the SSTA south of this section. In order to further understand the origins of this SSTA dipole, the respective contributions of the heat advected by the AMOC versus the Ekman transport and air?sea fluxes have been assessed. We found that at a 5-month lag, the Ekman component mainly contributes to the southern part of the dipole and cumulative air?sea fluxes only explain a small fraction of the SSTA variability. Given that the southern part of the SSTA dipole encompasses the main development region for Atlantic hurricanes, our results therefore suggest the potential for AMOC observations from 26 ? N to be used to complement existing seasonal hurricane forecasts in the Atlantic. JF - Climate Dynamics VL - 46 KW - Atlantic meridional overturning circulation KW - RAPID array KW - Seasonal potential predictability KW - Sea surface temperature KW - Air?sea heat flux SN - 0930-7575 TI - Potential for seasonal prediction of the Atlantic sea surface temperatures using the RAPID array at 26°N SP - 3351 AV - public EP - 3370 ER - TY - JOUR ID - soton362284 UR - https://eprints.soton.ac.uk/362284/ IS - 3 A1 - Duchez, Aurélie A1 - Frajka-Williams, Eleanor A1 - Castro, Natalia A1 - Hirschi, Joël A1 - Coward, Andrew Y1 - 2014/03// N2 - The meridional interior flow obtained from the RAPID array is determined by horizontal density fluctuations at the eastern and western boundary of 26°N. The physical causes of these density variations are responsible for fluctuations in the Atlantic Meridional Overturning Circulation (AMOC) and through it, the meridional heat transport of the Atlantic. In this modelling study, a high resolution ocean model is used to investigate the source and origin of the AMOC variability associated with the density fluctuations at the eastern boundary. The AMOC in the model is in good agreement with the RAPID observations and appears to adequately represent the smaller scale features of variability around the Canary Islands. In this paper, we identify a robust relationship between the density structure south of the Canary Islands, the local wind stress curl (WSC) around these islands and the AMOC using an empirical orthogonal functions analysis, wavelet transform and wavelet coherence. We find that the deep density fluctuations at the eastern boundary of 26°N arise from the pumping effect of the spatial pattern of WSC south of the islands. These deep density fluctuations drive the AMOC both on seasonal and interannual timescales, through their influence on the basinwide tilt of the thermocline. At seasonal timescales, the density fluctuations south of the islands are driven by the WSC and directly influence the AMOC. At interannual timescales, a significant coherence is found between the density fluctuation and the southward UMO transport although the origin of these density fluctuations is not explained by the direct pumping caused by the WSC. JF - Journal of Geophysical Research VL - 119 KW - Physical oceanography KW - Atlantic Meridional Overturning Circulation (AMOC) KW - Canary Islands KW - Seasonal / interannual variability KW - density fluctuations KW - Wind Stress Curl (WSC) SN - 0148-0227 TI - Seasonal to interannual variability in density around the Canary Islands and their influence on the Atlantic meridional overturning circulation at 26°N SP - 1843 AV - public EP - 1860 ER - TY - JOUR ID - soton2120 UR - https://eprints.soton.ac.uk/2120/ IS - 6 A1 - Ducklow, H.W. A1 - Kirchman, D.L. A1 - Anderson, T.R. Y1 - 2002/// JF - Limnology and Oceanography VL - 47 KW - NORTH ATLANTIC OCEAN KW - ATLN KW - BACTERIA KW - DISSOLVED ORGANIC CARBON KW - CARBON CYCLE KW - BIOLOGY SN - 0024-3590 TI - The magnitude of spring bacterial production in the North Atlantic Ocean SP - 1684 AV - none EP - 1693 ER - TY - JOUR ID - soton360974 UR - https://eprints.soton.ac.uk/360974/ A1 - Duffy, Grant A. A1 - Horton, Tammy A1 - Sheader, Martin A1 - Thurston, Michael H. Y1 - 2013/12/15/ N2 - This study focussed on the common and ubiquitous scavenging amphipod Abyssorchomene abyssorum collected from a section of the Mid-Atlantic Ridge with one pair of sampling areas at 49°N and the other at 54°N, north and south of the Charlie Gibbs Fracture Zone (CGFZ) and east and west of the ridge, at a water depth of 2500 m. Baited-trap samples of necrophagous amphipods were collected during three research expeditions on the RRS James Cook in 2007, 2009, and 2010, allowing for direct comparisons to be made amongst populations of A. abyssorum at the four sample areas. Random subsamples of 200 individuals from nine trap samples were sexed, dissected, and measured.

Males, females, and juveniles were found in all samples but no ovigerous females were identified. The finding of sexually mature mid-sized females, variability of oocyte size with body size, and presence of mature females with ?empty? ovaries, suggest that A. abyssorum is capable of having multiple broods in a lifetime. This reproductive strategy is beneficial to a scavenging organism living under a variable and unpredictable nutrient regime, allowing for a rapid reproductive response to advantageous conditions. Females north and south of the CGFZ fall into distinct cohorts with different distributional parameters. The total body lengths of female cohorts south of the CGFZ were consistently larger than those in the north. This is likely due to increased nutrient availability at the southern sampling areas.

Males were significantly smaller than females and possessed longer, more articulate antennae. Longer antennae are thought to facilitate mate-searching by males. Estimates of the maximum brood size ranged from 36?78 offspring with actual brood size expected to be at the lower end of this scale. This places the estimated brood size of A. abyssorum in a similar range to that of other scavenging amphipods of comparable size. The juvenile:non-juvenile ratio differed north and south of the CGFZ with significantly more juveniles in the north. Possible reasons for this difference are discussed. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 98 KW - Amphipoda KW - Mid-Atlantic Ridge KW - Population ecology KW - Scavengers KW - Bathyal SN - 0967-0645 TI - Population structure of Abyssorchomene abyssorum () (Amphipoda: Lysianassoidea), a scavenging amphipod from the Mid-Atlantic Ridge in the vicinity of the Charlie-Gibbs Fracture Zone SP - 360 AV - none EP - 369 ER - TY - JOUR ID - soton12670 UR - https://eprints.soton.ac.uk/12670/ IS - 1 A1 - Evangelidis, C. A1 - Minshull, T.A. A1 - Henstock, T.J. Y1 - 2004/// N2 - We present a crustal velocity and Moho depth model of the Ascension volcanic edifice using one of the most densely sampled 3-D wide-angle data sets for volcanic islands currently available. We invert traveltimes of first and second arrivals by seeking a layer-interface minimum structure model, and then test the resulting velocity model by gravity modelling and a 3-D checkerboard resolution test. Within the shallow extrusive part of the crust, two main high-velocity regions coincide with the highest topography on land and the gravity maximum off the west coast of the island, respectively. These features are connected with a high-velocity intrusive core that is created either within or on the top of oceanic layer 3 and is interpreted as a possible relic magma chamber. The thickness of the surface low-velocity region is similar to that observed at Hawaii, Jasper seamount and Great Meteor seamount, suggesting a similar process of edifice construction. The mean density of the volcanic edifice is significantly less than that of normal oceanic crust and than load densities typically assumed in studies of flexure as a result of seamount loading. There is no simple flexural model that explains the shape of the Moho beneath the island, perhaps because of the long-lived volcanism and the proximity of the island to the Mid-Atlantic Ridge (MAR) and the Ascension fracture zone. There is no evidence for magmatic underplating beneath Ascension Island. JF - Geophysical Journal International VL - 159 KW - 3D checkerboard KW - flexure KW - high-velocity anomaly KW - seismic tomography KW - south atlantic ocean KW - volcanic islands SN - 0956-540X TI - Three-dimensional crustal structure of Ascension Island from active source seismic tomography SP - 311 AV - restricted EP - 325 ER - TY - JOUR ID - soton383523 UR - https://eprints.soton.ac.uk/383523/ IS - 4 A1 - Ezer, Tal A1 - Haigh, Ivan D. A1 - Woodworth, Phillip L. Y1 - 2016/07// N2 - Nonlinear trends and long-term variability in sea-level measured on U.K. and western European coasts with long tide gauge records (~100-200 years) are investigated. Two different analysis ethods, a standard quadratic regression and a non-parametric, Empirical Mode Decomposition, detect similar positive sea-level accelerations over the past ~150 years: 0.014±0.003 and 0.012±0.004mm/y2, respectively; these values are close to the sea-level acceleration of the global ocean over the same period as reported by several studies. Ensemble calculations with added white noise are used to evaluate the robustness of low-frequency oscillations and estimate potential errors. Sensitivity experiments evaluate the impact of data gaps on the ability of the analysis to detect decadal variations and acceleration in sea-level. The long-term oscillations have typical periods of 15-60 years and range of 50-80 mm; these oscillations appear to be influenced by the North Atlantic Oscillation and by the Atlantic Multi-decadal Oscillation. Analysis of altimeter data over the entire North Atlantic Ocean shows that the highest impact of the North Atlantic Oscillation is on sea-level variability in the North Sea and the Norwegian coasts, while the Atlantic Multi-decadal Oscillation has the largest correlation with sea-level in the sub-polar gyre and the Labrador Sea, west of the study area. JF - Journal of Coastal Research VL - 32 KW - sea-level oscillations KW - sea-level acceleration KW - empirical mode decomposition KW - North Atlantic oscillations SN - 0749-0208 TI - Nonlinear sea-level trends and long-term variability on western European coasts SP - 744 AV - none EP - 755 ER - TY - JOUR ID - soton457542 UR - https://eprints.soton.ac.uk/457542/ IS - 13 A1 - Fabbrini, Alessio A1 - Zaminga, Ilaria A1 - Ezard, Thomas A1 - Wade, B.S. N2 -

The taxonomy and phylogeny of the Miocene to Recent genus Sphaeroidinellopsis have been documented in previous studies, but the evolution of this lineage remains unclear. Some authors have debated this genus in the past, choosing a variety of parameters to discriminate the morphospecies. Here we present new scanning electron microscope analyses of specimens from Ocean Drilling Program (ODP) Site 925 (Ceara Rise, western equatorial Atlantic) and ODP Site 959 (Deep Ivorian Basin, eastern equatorial Atlantic). Our study reveals transitional individuals Sphaeroidinellopsis disjuncta?Sphaeroidinellopsis kochi, a speciation event never described previously. These transitional specimens are characterized by extreme morphological features such as elongated and sac-like final chambers, requiring amendments to the current classification and taxonomy of these morphospecies. In this paper, an alternative hypothesis is presented and discussed, to assess these new observations within the evolutionary mosaic of Sphaeroidinellopsis.

VL - 19 TI - Systematic taxonomy of middle miocene sphaeroidinellopsis (planktonic foraminifera) AV - public EP - 968 N1 - Funding Information: We thank Jim Davy for assistance with SEM and his help during the preparation process. This research used samples provided by the International Ocean Discovery Program (IODP) and its predecessors. AF and BW were supported by the Natural Environment Research Council (grant number NE/P019013/1); THGE was supported by the Natural Environment Research Council (grant number NE/P019269/1). The authors are very grateful to Dr Adriane Lam and the anonymous reviewer for their taxonomic comments and help in improving the manuscript. Funding Information: We thank Jim Davy for assistance with SEM and his help during the preparation process. This research used samples provided by the International Ocean Discovery Program (IODP) and its predecessors. AF and BW were supported by the Natural Environment Research Council (grant number NE/P019013/1); THGE was supported by the Natural Environment Research Council (grant number NE/P019269/1). The authors are very grateful to Dr Adriane Lam and the anonymous reviewer for their taxonomic comments and help in improving the manuscript. Publisher Copyright: © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Y1 - 2021/12/13/ JF - Journal of Systematic Palaeontology KW - Atlantic Ocean KW - Miocene KW - Sphaeroidinellopsis KW - evolution KW - planktonic foraminifera KW - taxonomy SN - 1477-2019 SP - 953 ER - TY - JOUR N1 - 9th International Conference on Artificial Reefs and Related Aquatic Habitats (CARAH) ID - soton201423 UR - https://eprints.soton.ac.uk/201423/ A1 - Fabi, G. A1 - Spagnolo, A. A1 - Bellan-Santini, D. A1 - Charbonnel, E. A1 - Cicek, B.A. A1 - Garcia, J.J.G. A1 - Jensen, Antony C. A1 - Kallianiotis, A. A1 - dos Santos, M.N. Y1 - 2011/// N2 - Artificial reefs in Europe have been developed over the last 40 yrs. Most of these reefs have been placed in the Mediterranean Sea, but there is an increasing interest on the part of northern European countries. Fish stock enhancement and fishery management are the main purposes of reef construction in the Mediterranean Sea and on the Atlantic coast of the Iberian Peninsula, while nature conservation/restoration, research, and recreation have been the main purposes served in the other European regions to date. Artificial reef deployment falls under some general regulations concerning the protection of the sea against pollution due to the dumping of unsuitable materials. Specific Regional Plans relating to the use of artificial reefs in the marine environment and Guidelines for reef construction have been derived from these general regulations. In spite of recent developments, national and/or regional programs for the deployment of artificial reefs and/or their inclusion in overall management plans for integrated management of coastal zones are in force only in the majority of Mediterranean countries, while only a few projects have, to date, been undertaken in the other European Regions. Moreover, there is a noteworthy lack of plans, in many countries, for the management of the reefs after their deployment. JF - Brazilian Journal of Oceanography VL - 59 KW - Artificial reefs KW - Management KW - Baltic KW - Mediterranean KW - NW Atlantic KW - Black Sea SN - 1679-8759 TI - Overview on artificial reefs in Europe SP - 155 AV - none EP - 166 ER - TY - JOUR ID - soton7908 UR - https://eprints.soton.ac.uk/7908/ IS - 1/4 A1 - Fabiano, M. A1 - Pusceddu, A. A1 - Dell'anno, A. A1 - Armeni, M. A1 - Vanucci, S. A1 - Lampitt, R.S. A1 - Wolff, G.A. A1 - Danovaro, R. Y1 - 2001/// N2 - Downward fluxes of labile organic matter (phytopigments, proteins and carbohydrates) were measured between September 1996 and August 1998 at three depths 1000 m, 3000 m and 4700 m (c. 100 mab) over the Porcupine Abyssal Plain (PAP, NE Atlantic), to provide detailed information on the biochemical characteristics of organic inputs to the deep sea. Temporal changes in the carbohydrate and protein fluxes were compared to carbohydrate and protein contents of the surficial sediment on the seabed beneath the traps at 4850 m depth. Fluxes of carbohydrate, protein and phytopigments (chlorophylls-a and -b, and phaeophytins-a and -b) displayed strong seasonal variations, but limited interannual variability between the two years of measurement. Fluxes of labile organic matter were characterised by strong pulses which occurred in spring and early summer, suggesting that the deep PAP area experiences relatively predictable patterns of vertical fluxes. No major quantitative differences in organic matter fluxes were observed between traps at different depths, but highest carbohydrate fluxes (time-weighted mean 2.4 mg m?2 d?1) were observed at 4700 m, whereas highest protein fluxes were observed at 1000 m (time-weighted mean 2.1 mg m?2 d?1). Carbohydrate, protein and phytopigment fluxes were correlated significantly, suggesting that settling material was associated with primary organic matter (i.e., phytodetritus) inputs from the photic layer. The contributions of chlorophyll-a and -b, and of phaeophytin-a and -b did not change significantly with increasing depth. Nor did the ratio of total phaeopigments to total chlorophylls did change greatly with depth (0.3?0.4 at both 3000 m and 4700 m depth) suggesting that degradation rates in the sinking particles were low. Protein and carbohydrate concentrations in the sediments at 4850 m depth (collected during 6 cruises between 1996 and 1998) and vertical fluxes at 3000 m depth followed inverse temporal patterns; peak concentrations of protein in the sediment corresponded to low vertical fluxes of particulate proteins. These data suggest that there is a decoupling between pelagic input and benthic accumulation. However, bacterial secondary production and sedimentary RNA concentrations displayed temporal patterns similar to those of the vertical fluxes, suggesting that increases in the metabolism of the smallest-sized biota was associated with maxima in the organic matter supply. Our results also suggest that benthic utilisation could exceed the organic matter being supplied by the vertical fluxes. JF - Progress in Oceanography VL - 50 KW - NORTHEAST ATLANTIC OCEAN KW - PHYTOPIGMENTS KW - PROTEINS KW - CARBOHYDRATES SN - 0079-6611 TI - Fluxes of phytopigments and labile organic matter to the deep ocean in the NE Atlantic Ocean SP - 89 AV - none EP - 104 ER - TY - JOUR ID - soton28711 UR - https://eprints.soton.ac.uk/28711/ IS - 2 A1 - Fasham, M.J.R. A1 - Flynn, K.J. A1 - Pondaven, P. A1 - Anderson, T.R. A1 - Boyd, P.W. Y1 - 2006/// N2 - A new mixed layer multi-nutrient ecosystem model, incorporating diatoms, non-diatoms and zooplankton, is described that models the role of iron in marine biogeochemical cycles. The internal cell biochemistry of the phytoplankton is modelled using the mechanistic model of Flynn [2001. A mechanistic model for describing dynamic multi-nutrient, light, temperature interactions in phytoplankton. Journal of Plankton Research 23, 977?997] in which the internal cell concentrations of chlorophyll, nitrogen, silica, and iron are all dynamic variables that respond to external nutrient concentrations and light levels. Iron stress in phytoplankton feeds back into chlorophyll synthesis and changes in photosynthetic unit (PSU) size, thereby reducing their growth rate. Because diatom silicon metabolism is inextricably linked with cell division, diatom population density (cell m?3) is modelled as well as C biomass. An optimisation technique was used to fit the model to three time-series datasets at Biotrans (47°N, 20°W) and Kerfix (50°40?S, 68°25?E) and the observations for the Southern Ocean Iron-Release Experiment (SOIREE) iron-enrichment experiment (61°S, 140°E). The model gives realistic simulations of the annual cycles of nutrients, phytoplankton, and primary production at Biotrans and Kerfix and can also accurately simulate an iron fertilisation experiment. Specifically, the model predicts the high values of diatom Si:N and Si:C ratios observed in areas where iron is a limiting factor on algal growth. In addition, the model results at Kerfix confirm previous suggestions that underwater light levels have a more limiting effect on phytoplankton growth than iron supply. The model is also used to calculate C budgets and C and Si export from the mixed layer. The implications of these results for developing biogeochemical models incorporating the role of iron are discussed. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 53 KW - ecosystem model KW - iron limitation KW - diatom growth KW - carbon budgets KW - nutrient cycles KW - export flux KW - Southern Ocean KW - Kerguelen Islands time-series station KW - SOIREE site KW - North Atlantic KW - Biotrans station SN - 0967-0637 TI - Development of a robust ecosystem model to predict the role of iron on biogeochemical cycles: a comparison of results for iron-replete and iron-limited areas, and the SOIREE iron-enrichment experiment SP - 333 AV - none EP - 366 ER - TY - JOUR ID - soton453897 UR - https://eprints.soton.ac.uk/453897/ A1 - Fernández-Castro, B. A1 - Arístegui, J. A1 - Anderson, L. A1 - Montero, M. F. A1 - Hernández-León, S. A1 - Marañón, E. A1 - Mouriño-Carballido, B. Y1 - 2016/09/01/ N2 - Remineralization of organic matter in the mesopelagic zone (ca. 150-700 m) is a key controlling factor of carbon export to the deep ocean. By using a tracer conservation model applied to climatological data of oxygen, dissolved inorganic carbon (DIC) and nitrate, we computed mesopelagic respiration near the ESTOC (European Station for Time-Series in the Ocean, Canary Islands) site, located in the Eastern boundary region of the North Atlantic subtropical gyre. The tracer conservation model included vertical Ekman advection, geostrophic horizontal transport and vertical diffusion, and the biological remineralization terms were diagnosed by assuming steady state. Three different approaches were used to compute reference velocities used for the calculation of geostrophic velocities and flux divergences: a no-motion level at 3000 m, surface geostrophic velocities computed from the averaged absolute dynamic topography field, and surface velocities optimized from the temperature model. Mesopelagic respiration rates computed from the model were 2.8-8.9 mol O2 m2 y-1, 2.0-3.1 mol C m2 y-1 and 0.6-1.0 mol N m2 y-1, consistent with remineralization processes occurring close to Redfield stoichiometry. Model estimates were in close agreement with respiratory activity, derived from electron transport system (ETS) measurements collected in the same region at the end of the winter bloom period (3.61±0.48 mol O2 m-2 y-1). According to ETS estimates, 50% of the respiration in the upper 1000 m took place below 150 m. Model results showed that oxygen, DIC and nitrate budgets were dominated by lateral advection, pointing to horizontal transport as the main source of organic carbon fuelling the heterotrophic respiration activity in this region. JF - Deep-Sea Research Part I: Oceanographic Research Papers VL - 115 KW - ESTOC KW - Horizontal advection KW - Mesopelagic respiration KW - North Atlantic subtropical gyre KW - Tracer conservation model SN - 0967-0637 TI - Mesopelagic respiration near the ESTOC (European Station for Time-Series in the Ocean, 15.5°W, 29.1°N) site inferred from a tracer conservation model SP - 63 AV - public EP - 73 ER - TY - JOUR ID - soton453896 UR - https://eprints.soton.ac.uk/453896/ IS - 4 A1 - Fernández-Castro, B. A1 - Pahlow, M. A1 - Mouriño-Carballido, B. A1 - Marañón, E. A1 - Oschlies, A. Y1 - 2016/08/01/ N2 - A recent optimality-based model for phytoplankton growth and diazotrophy was applied at two stations located in the oligotrophic western and the ultra-oligotrophic eastern subtropical North Atlantic. Contrary to the common view that diazotrophy is favoured by nitrogen (N) depletion relative to the Redfield equivalent of phosphorus (P), we find that optimality-based diazotrophy could explain N fixation in both regions in spite of relatively high N:P supply ratios. This is possible because the availability of an additional source of N for diazotrophs makes them strong competitors for P under oligotrophic conditions. The best reproduction of observations, especially of net primary production, is only achieved with preferential remineralization of P relative to N and atmospheric deposition. In line with observations, a higher rate of nitrogen fixation is predicted for the eastern site, owing to a larger niche for diazotrophs resulting from stronger oligotrophy and lower N:P supply ratios due to weaker atmospheric N deposition. Because the competitive advantage of diazotrophs under nutrient starvation diminishes with increasing supply N:P ratio, the predicted increase of atmospheric N deposition due to anthropogenic activity could negatively affect N2 fixation in the Atlantic Ocean. JF - Journal of Plankton Research VL - 38 KW - Atmospheric deposition KW - Nitrogen fixation KW - Optimality-based model KW - Preferential remineralization KW - Subtropical North Atlantic SN - 0142-7873 TI - Optimality-based Trichodesmium diazotrophy in the North Atlantic subtropical gyre SP - 946 AV - none EP - 963 ER - TY - JOUR ID - soton453586 UR - https://eprints.soton.ac.uk/453586/ A1 - Fernández-Castro, Bieito A1 - Mouriño-Carballido, Beatriz A1 - Álvarez-Salgado, Xosé Antón Y1 - 2019/02/01/ N2 - The eastern boundary of the North Atlantic subtropical gyre (NASTG) receives organic materials produced in the nearby Canary upwelling system (CanUS), which has important implications for the metabolic balance of the region. Here we computed absolute geostrophic, Ekman and eddy diffusive transports and net budgets of oxygen, nitrate, and phosphate, with an inverse model applied to annual climatologies from the World Ocean Atlas 2013, in a large box covering the eastern boundary of the NASTG. The surface waters (<100?m) of the box exported ?mol?O2?m?2?yr?1 to the adjacent ocean and atmosphere, and imported ?mol?N?m?2?yr?1 and ?mmol?P?m?2?yr?1 of nitrate and phosphate, respectively, indicating that net autotrophy prevailed in the euphotic waters of the eastern NASTG. The central, intermediate and deep waters (100?m-bottom) imported ?mol?O2?m?2?yr?1, and exported ?mol?N?m?2?yr?1 and ?mmol?P?m?2?yr?1 of nitrate and phosphate, respectively, indicative of net remineralization. Mesopelagic remineralization rates exceeded epipelagic net community production, implying a net deficit of carbon and nutrients in the region. Remineralization occurred at high N:P molar ratios (28) in central waters, and thus, a excess nitrate (DINxs?=?NO3-16PO4) was produced at a rate of ?mol?N?yr?1. This excess nitrate was exported to the gyre interior, influencing the biogeochemistry of the whole NASTG and leaving the eastern margin with a strong nitrogen deficit, relative to carbon and phosphorus. According to the available literature, the organic carbon export from the CanUS could be sufficient to account for the carbon deficit, but the source of nitrogen remains elusive. JF - Progress in Oceanography VL - 171 KW - Eastern North Atlantic subtropical gyre KW - Excess nitrate KW - Metabolic balance KW - Nutrient cycling KW - Redfield ratios KW - Remineralization SN - 0079-6611 TI - Non-redfieldian mesopelagic nutrient remineralization in the eastern North Atlantic subtropical gyre SP - 136 AV - none EP - 153 ER - TY - CHAP ID - soton6001 UR - https://eprints.soton.ac.uk/6001/ A1 - Ferreira, P. A1 - Pinto, A. A1 - Murton, B. A1 - Monteiro, H. A1 - Magalhaes, V. A1 - Salgueiro, E. A1 - Lopes, C. A1 - Quartau, R. A1 - Stepanov, A. Y1 - 2001/// PB - Intergovernmental Oceanographic Commission T3 - 175 KW - MID ATLANTIC RIDGE KW - HYDROTHERMAL DEPOSITS KW - GEOLOGY TI - Hydrothermal geological materials from Lucky Strike field collected during TTR-10/leg 2, Azores, Mid Atlantic Ridge SP - 74 AV - none EP - 76 T2 - Geological Processes on Deep-Water European Margins: International Conference and Ninth Post-Cruise Meeting of the Training-Through-Research Programme, devoted to the 10th Anniversary, Moscow-Mozhenka, Russia, 28 January-2 February 2001 ER - TY - JOUR ID - soton13969 UR - https://eprints.soton.ac.uk/13969/ IS - 13-14 A1 - Fones, G.R. A1 - Davison, W. A1 - Hamilton-Taylor, J. Y1 - 2004/// N2 - Vertical profiles of trace metals were measured at 1-mm intervals by deploying DGT probes in sediment cores collected from the deep Atlantic Ocean (Feni Drift) before and after the spring phytoplankton bloom. DGT (diffusive gradients in thin-films) accumulates metals on a chelating resin after their diffusive transport through a layer of hydrogel. The mean concentration of metal in the porewaters at the surface of the device during its deployment was derived from the measured mass of metal. Well-defined laboratory systems were used to establish the reproducibility and accuracy of the DGT technique for measuring metals at 1-mm intervals. The Fe and Mn profiles showed the expected redox sequence with depth, with additional fine-scale (2?5 mm) features. The close correspondence between the Mn and Co profiles, on both coarse and fine scales, showed that their chemistry is closely coupled in sediments as well as water columns. Changes in the background concentrations of Cd, Cu, Ni and Zn with depth were well correlated with Mn and Co, but the four metals also displayed mm-scale maxima that were largely independent of Mn, Co or Fe. Two-dimensional measurements at a 100-?m resolution on a DGT probe, deployed in situ with an autonomous lander, showed that the maxima were most likely associated with near-spherical, highly localised sources. The results were consistent with release of Cd, Cu, Ni and Zn from organic and planktonic skeletal material. Where there was associated release of Mn and/or Fe, through their oxides acting as electron acceptors in the decomposition of the organic matter, trace metals could also be supplied by release from the oxides. The microniches responsible for high local concentrations of metals in the porewaters were hypothesised to be due to downward mixing of material by burrowing organisms, known to be prevalent in these sediments. Much of this material appeared to be present as faecal pellets of various origins, with sizes in the range of to 1 cm JF - Continental Shelf Research VL - 24 KW - Atlantic KW - Trace metals KW - DGT KW - Sediments KW - Pore waters KW - Benthic SN - 0278-4343 TI - The fine-scale remobilization of metals in the surface sediment of the North-East Atlantic SP - 1485 AV - none EP - 1504 ER - TY - JOUR ID - soton338078 UR - https://eprints.soton.ac.uk/338078/ A1 - Forryan, A. A1 - Martin, A.P. A1 - Srokosz, M.A. A1 - Popova, E.E. A1 - Painter, S.C. A1 - Stinchcombe, M.C. Y1 - 2012/// N2 - As part of a multidisciplinary cruise to the Iceland Basin in July?August 2007, near to the historical JGOFS Ocean Weather Station India site (?59° N, ?19° W), observations were made of vertical turbulent nutrient fluxes around an eddy dipole, a strong mesoscale feature consisting of a cyclonic eddy and an anti-cyclonically rotating mode-water eddy. Investigation of the spatial distribution of vertical turbulent diffusivity around the dipole shows an almost uniform horizontal distribution despite the strong horizontal gradients in water velocity and density observed. An area mean turbulent diffusivity was calculated as 0.21 (95% confidence interval: 0.17?0.26)×10?4 m2 s?1 at the base of the euphotic zone. The vertical turbulent fluxes of three major macro-nutrients into the euphotic zone were calculated as 0.13 (95% confidence interval 0.08?0.22) mmol m?2 day?1 for nitrate, 0.08 (0.05?0.12) mmol m?2 day?1 for silicate and, 8.6 (13.0?5.2 )×10?3 mmol m?2 day?1 for phosphate. The vertical turbulent flux of dissolved iron (dFe) into the euphotic zone was calculated to be 2.6 (95% confidence interval 1.3?4.3)×10?6 mmol m2 day?1. Turbulent macro-nutrient flux is estimated to contribute up to 14% of the deep winter mixing supply of silicate, nitrate and phosphate in the region. The magnitude of turbulent dFe flux is estimated to be at most 8% of the deep winter mixing supply of dFe. Deep winter mixing is hypothesised to supply an adequate amount of iron to fully utilise the deep winter mixed supply of silicate but not the deep winter mixed supply of nitrate. This suggests that while the iron supply may not limit the magnitude of the spring bloom, iron limitation may be occurring post bloom. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 63 KW - Nitrate KW - Silicate KW - Phosphate KW - Dissolved iron KW - Turbulent diffusion KW - North Atlantic SN - 0967-0637 TI - Turbulent nutrient fluxes in the Iceland Basin SP - 20 AV - none EP - 35 ER - TY - JOUR ID - soton49693 UR - http://www.agu.org/journals/pa/pa0701/2006PA001349/ IS - 1 A1 - Forster, A. A1 - Schouten, S. A1 - Moriya, K. A1 - Wilson, P.A. A1 - Damste, J.S.S. Y1 - 2007/03// N2 - Oceanic anoxic event 2 (OAE-2) occurring during the Cenomanian/Turonian (C/T) transition is evident from a globally recognized positive stable carbon isotopic excursion and is thought to represent one of the most extreme carbon cycle perturbations of the last 100 Myr. However, the impact of this major perturbation on and interaction with global climate remains unclear. Here we report new high-resolution records of sea surface temperature (SST) based on TEX86 and ?18O of excellently preserved planktic foraminifera and stable organic carbon isotopes across the C/T transition from black shales located offshore Suriname/French Guiana (Demerara Rise, Ocean Drilling Program Leg 207 Site 1260) and offshore Senegal (Cape Verde Basin, Deep Sea Drilling Project Leg 41 Site 367). At Site 1260, where both SST proxy records can be determined, a good match between conservative SST estimates from TEX86 and ?18O is observed. We find that late Cenomanian SSTs in the equatorial Atlantic Ocean (?33°C) were substantially warmer than today (~27°?29°C) and that the onset of OAE-2 coincided with a rapid shift to an even warmer (~35°?36°C) regime. Within the early stages of the OAE a marked (~4°C) cooling to temperatures lower than pre-OAE conditions is observed. However, well before the termination of OAE-2 the warm regime was reestablished and persisted into the Turonian. Our findings corroborate the view that the C/T transition represents the onset of the interval of peak Cretaceous warmth. More importantly, they are consistent with the hypotheses that mid-Cretaceous warmth can be attributed to high levels of atmospheric carbon dioxide (CO2) and that major OAEs were capable of triggering global cooling through the negative feedback effect of organic carbon-burial-led CO2 sequestration. Evidently, however, the factors that gave rise to the observed shift to a warmer climate regime at the onset of OAE-2 were sufficiently powerful that they were only briefly counterbalanced by the high rates of carbon burial attained during even the most extreme interval of organic carbon burial in the last 100 Myr. JF - Paleoceanography VL - 22 KW - Cretaceous KW - tropical KW - sea surface temperatures KW - equatorial Atlantic KW - oceanic anoxic event KW - Cenomanian/Turonian transition SN - 0883-8305 TI - Tropical warming and intermittent cooling during the Cenomanian/Turonian oceanic anoxic event 2: Sea surface temperature records from the equatorial Atlantic AV - none ER - TY - JOUR ID - soton422949 UR - https://eprints.soton.ac.uk/422949/ IS - 297 A1 - Fragoso, Glaucia A1 - Poulton, Alex A1 - Yashayaev, Igor M. A1 - Head, Erica J.H. A1 - Johnsen, Geir A1 - Purdie, Duncan A. Y1 - 2018/09/05/ N2 - Diatoms are a keystone algal group, with diverse cell morphology and a global distribution. The biogeography of morphological, functional and life-history traits of marine diatoms were investigated in Arctic and Atlantic waters of the Labrador Sea during the spring bloom (2013-2014). In this study, trait-based analysis using community-weighted means showed that low temperatures (<0ºC) in Arctic waters correlated positively with diatom species that have traits such as low temperature optimum growth and the ability to produced ice-binding proteins, highlighting their sea-ice origin. High silicate concentrations in Arctic waters, as well as sea-ice cover and shallow bathymetry, favoured diatom species that were heavily silicified, colonial and capable of producing resting spores, suggesting that these are important traits for this community. In Atlantic waters, diatom species with large surface area to volume ratios were dominant in deep mixed layers, whilst low silicate to nitrate ratios correlated positively with weakly silicified species. Sharp cell projections, such as processes or spines, were positively correlated with water-column stratification, indicating that these traits promote positive buoyancy for diatom cells. Our trait-based analysis directly links cell morphology and physiology with diatom species distribution, highlighting allowing new insights on how this method can potentially be applied to explain ecophysiology and shifting biogeographical distributions in a warming climate JF - Frontiers in Marine Science VL - 5 KW - Arctic KW - Atlantic KW - Marine diatom KW - Trait-based approaches KW - biogeography SN - 2296-7745 TI - Diatom biogeography from the Labrador Sea revealed through a trait-based approach SP - 1 AV - public EP - 15 ER - TY - JOUR ID - soton143703 UR - https://eprints.soton.ac.uk/143703/ IS - 4 A1 - Frajka-Williams, Eleanor A1 - Rhines, Peter B. Y1 - 2010/04// N2 - We investigated the variability of the spring phytoplankton bloom in the Labrador Sea, dividing into distinct biogeographical zones, then analyzing the relationship between the bloom and physical forcings. The spring phytoplankton bloom in the north Labrador Sea varied in intensity by a factor of 4 and in timing of onset by 3 weeks over the 11-year record from SeaWiFS satellite ocean chlorophyll, 1998?2008. This north bloom (north of 60 °N and west of the Labrador shelves) is earliest and most intense, owing in part to the offshore-directed freshwater stratification from the West Greenland Current. On interannual timescales, significant correlations were found between the north bloom intensity and ocean processes, namely offshore advection, eddy activity and runoff from Greenland. In contrast, the central Labrador Sea is later and weaker, and only a correlation between the bloom timing and irradiance was found. As the subpolar gyre shifts in strength and shape, freshwater outflow from the Arctic and Greenland changes, we may expect further changes in the biological response as indicated by these relationships. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 57 KW - seawifs KW - spring bloom KW - physical controls KW - biophysical interactions KW - interannual variability KW - subpolar north atlantic KW - labrador sea SN - 0967-0637 TI - Physical controls and interannual variability of the Labrador Sea spring phytoplankton bloom in distinct regions SP - 541 AV - public EP - 552 ER - TY - JOUR ID - soton49994 UR - https://eprints.soton.ac.uk/49994/ IS - 1 A1 - Friedrich, O. A1 - Hemleben, C. Y1 - 2007/01/10/ N2 - Benthic foraminiferal faunas from the Lower Maastrichtian (Globotruncana falsostuarti?Gansserina gansseri Planktic Foraminiferal Zone) of DSDP Site 390 (Blake Nose, western North Atlantic) were investigated in order to characterize changes in organic matter flux and bottom-water oxygenation and their relation to paleoceanographic changes. Benthic foraminiferal faunas in the lower part of the studied succession show high abundances of Praebulimina reussi and Nuttallides truempyi and are proposed to reflect fluctuations in organic matter flux to the seafloor (meso- to eutrophic) under oxygenated bottom-water conditions. The middle interval is characterized by very low numbers of benthic foraminiferal specimens but a dominance of thick-walled species (e.g., lenticulinids, laevidentalinids), may reflect carbonate dissolution. In contrast to the lower part, benthic foraminifera from the upper part of the succession show well-oxygenated bottom waters. The most dominant species during this interval are Gavelinella beccariiformis, Reussella szajnochae, and N. truempyi. Parallel to this change in the benthic foraminiferal assemblages the number of inoceramid shells decreases, reflecting a significant increase in bottom-water oxygenation. Based on these data we speculate, that the observed changes in benthic foraminiferal assemblages towards a well-oxygenated environment within the Early Maastrichtian of DSDP Site 390 could reflect the onset of a shift from low-latitude to high-latitude deep-water sources. This speculation will predate the major reorganization of the oceanic circulation resulting in a circulation mode similar to today at the Early/Late Maastrichtian boundary by 1 Ma.
JF - Marine Micropaleontology VL - 62 KW - Cretaceous KW - ocean circulation KW - North Atlantic KW - benthic foraminifera KW - Maastrichtian SN - 0377-8398 TI - Early Maastrichtian benthic foraminiferal assemblages from the western North Atlantic (Blake Nose) and their relation to paleoenvironmental changes SP - 31 AV - none EP - 44 ER - TY - JOUR ID - soton49985 UR - https://eprints.soton.ac.uk/49985/ IS - 1-2 A1 - Friedrich, O. A1 - Herrle, J.O. A1 - Koessler, P. A1 - Hemleben, C. Y1 - 2004/08/19/ N2 - We propose that the observed short-term stable isotope fluctuations reflect changes in high- and low-latitude intermediate to deep water sources, based on a high-resolution stable isotope record of planktic and benthic foraminifera from the Early Maastrichtian (71.3 to 69.6 Ma) of Blake Nose (DSDP Site 390A, North Atlantic). Sources of these waters may have been the low-latitude eastern Tethys and high-latitude North Atlantic. Changes in intermediate to deep water sources were probably steered by eccentricity-controlled insolation fluctuations. Lower insolation favored the formation of high-latitude deep waters due to positive feedback mechanisms resulting in high-latitude cooling. This led to a displacement of low-latitude deep waters at Blake Nose. Higher insolation reduced intermediate to deep-water formation in high latitudes, yielding a more northern flow of low-latitude deep waters.
JF - Palaeogeography, Palaeoclimatology, Palaeoecology VL - 211 KW - Cretaceous climate KW - Ocean circulation KW - North Atlantic KW - Stable isotopes SN - 0031-0182 TI - Early Maastrichtian stable isotopes: Changing deep water sources in the North Atlantic? SP - 171 AV - none EP - 184 ER - TY - JOUR ID - soton49992 UR - https://eprints.soton.ac.uk/49992/ IS - 2 A1 - Friedrich, O. A1 - Schmiedl, G. A1 - Erlenkeuser, H. Y1 - 2006/01// N2 - The stable carbon and oxygen isotope composition of different benthic foraminiferal species of the latest Campanian and earliest Maastrichtian from Ocean Drilling Project Hole 690C (Weddell Sea, southern South Atlantic, 1800 m paleowater depth) have been investigated. The total range of measured isotope values of all samples exceeds 4? for ?13C and 1.1? for ?18O. Carbon isotope values of proposed deep infaunal species are generally similar or only slightly lower when compared to proposed epifaunal to shallow infaunal species. Interspecific differences vary between samples probably reflecting temporal changes in organic carbon fluxes to the sea floor. Constantly lower ?13C values for Pullenia marssoni and Pullenia reussi suggest the deepest habitat for these species. The strong depletion of ?13C values by up to 3? within lenticulinids may be attributed to a deep infaunal microhabitat, strong vital effects, or different feeding strategy when compared to other species or modern lenticulinids. The mean ?18O values reveal a strong separation of epifaunal to shallow infaunal and deep infaunal species. Epifaunal to shallow infaunal species are characterized by low ?18O values, deep infaunal species by higher values. This result possibly reflects lower metabolic rates and longer life cycles of deep infaunal species or the operating of a pore water [CO32?] effect on the benthic foraminiferal stable isotopes.

Pyramidina szajnochae shows an enrichment of oxygen isotopes with test size comprising a total of 0.6? between 250 and 1250 ?m shell size. Although ?13C lacks a corresponding trend these data likely represent the presence of changes in metabolic rates during ontogenesis. These results demonstrate the general applicability of multi-species stable isotope measurements of pristine Cretaceous benthic foraminifera to reconstruct past microhabitats and to evaluate biological and environmental effects on the stable isotope composition.
JF - Marine Micropaleontology VL - 58 KW - benthic foraminifera KW - stable isotopes KW - Campanian KW - Maastrichtian KW - South Atlantic SN - 0377-8398 TI - Stable isotope composition of Late Cretaceous benthic foraminifera from the southern South Atlantic: Biological and environmental effects SP - 135 AV - none EP - 157 ER - TY - JOUR ID - soton355633 UR - https://eprints.soton.ac.uk/355633/ IS - 2 A1 - Friedrich, Oliver A1 - Wilson, Paul A. A1 - Bolton, Clara T. A1 - Beer, Christopher J. A1 - Schiebel, Ralf Y1 - 2013/06// N2 - The strength and latitudinal position of the North Atlantic Current, NAC, determines the position of the Arctic front and heat transport to the high northern latitudes with potentially important consequences for Northern Hemisphere glaciation. A southward shift in the NAC and reduced poleward heat transport is hypothesized to have triggered the last major climate transition in Earth's history?late Pliocene intensification of Northern Hemisphere glaciation (iNHG). In turn, iNHG is hypothesized to have led to the amplification of climate variability on suborbital time scales. To date, however, only a handful of adequately resolved records are available to test these two hypotheses. Here we present a new late Pliocene to earliest Pleistocene record from Integrated Ocean Drilling Program Site U1313 (North Atlantic, 41°N; 2.9 to 2.4?Ma). We use Mg/Ca-derived paleotemperature records in planktic foraminiferal calcite to investigate changes in summer sea-surface temperatures (SST) on orbital and suborbital time scales. Our results call into question the suggestion that significant weakening and/or southward shift of the NAC served as a trigger for Northern Hemisphere cooling and intensified continental ice sheet growth across iNHG. In contrast to the late Pleistocene, during iNHG, we find that the position of the NAC and Arctic Front probably lay well to the north of Site U1313 and that the amplitude of suborbital SST variability did not change on glacial-interglacial time scales. Conservative estimates of Late Pliocene to earliest Pleistocene interglacial summer SSTs in our record are up to 3°C warmer than present, while glacial summer SSTs are only 2°C to 3°C cooler. In fact, our interglacial summer SSTs are remarkably similar to those of the mid-Pliocene. Our findings indicate that iNHG must have involved amplifying feedback mechanisms that are tightly coupled to ice sheet growth but that these processes were insufficiently developed by the late Pliocene/earliest Pleistocene to have triggered large amplitude changes in suborbital climate in the midlatitude North Atlantic. JF - Paleoceanography VL - 28 KW - Pliocene KW - planktic foraminifera KW - North Atlantic current SN - 0883-8305 TI - Late Pliocene to early Pleistocene changes in the North Atlantic Current and suborbital-scale sea-surface temperature variability SP - 274 AV - none EP - 282 ER - TY - JOUR ID - soton9728 UR - https://eprints.soton.ac.uk/9728/ IS - 6 A1 - Gage, J.D. A1 - Anderson, R.M. A1 - Tyler, P.A. A1 - Chapman, R. A1 - Dolan, E. Y1 - 2004/// N2 - Growth was studied from skeletal growth markers in the cosmopolitan abyssal brittle star Ophiocten hastatm. Samples for analysis were taken at five sites located in the southern (2900 m) and central (2000 m) Rockall Trough, at ca. 3000 and 4000 m in the Porcupine Seabight, and at 4850 m on the Porcupine Abyssal Plain. Growth bands were assumed to reflect an annual cycle in skeletal growth. Band measurements on arm vertebrae, standardised to disc diameter, were used to provide size-at-age data and size-increment data that took into account overgrowth of early bands in older individuals. The Richards growth function marginally provides best fit to pooled size-at-age data, although the asymptote-less Tanaka function and the Gompertz growth function also provided good fit to size-at-age data which showed a rather linear growth pattern with little indication of a growth asymptote. Loge transformed size-increment data were linearised by applying the Ford?Walford method to approximate Gompertz growth so that growth could be compared at the five sites. Grouped linear regression and analysis of covariance showed no significant differences between growth at the sites and a common fitted regression. However, pairwise comparisons suggest growth differences with increasing bathymetric separation. Oocyte size frequencies measured from histological preparations of the gonad of specimens from the Porcupine Abyssal Plain indicate marked reproductive periodicity, with spawn-out in late winter that is likely followed by planktotrophic early development in spring with benthic settlement in summer. Although usually rare in the trawl and epibenthic sled samples, several years of successful recruitment followed by a period when recruitment was low or absent might explain size structure observed in a single unusually large sample from the Rockall Trough. This is consistent with previous observations during the late 1990s of a large population increase on the Porcupine Abyssal Plain. Analysis of growth bands of these specimens sampled in 1997 suggest the population increase derives from a single or small number of year classes recruited during the early 1990s.
JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 51 KW - Ophiuroidea KW - Population dynamics KW - Growth comparison KW - Reproduction KW - Recruitment KW - Benthic environment KW - NE Atlantic KW - Rockall Trough KW - Porcupine Seabight KW - Porcupine Abyssal Plain SN - 0967-0637 TI - Growth, reproduction and possible recruitment variability in the abyssal brittle star Ophiocten hastatum (Ophiuroidea: Echinodermata) in the NE Atlantic SP - 849 AV - none EP - 864 ER - TY - JOUR ID - soton8020 UR - https://eprints.soton.ac.uk/8020/ IS - 1/4 A1 - Galeron, J. A1 - Sibuet, M. A1 - Vanreusel, A. A1 - MacKenzie, K. A1 - Gooday, A.J. A1 - Dinet, A. A1 - Wolff, G.A. Y1 - 2001/// N2 - Two major size classes of the sediment community, meiofauna and macrofauna, and four classes of lipid compounds, fatty acids, alkanes, alcohols and sterols, were investigated using multicorer and USNEL boxcorer samples, collected during six cruises over a two year period (September 1996 to September?October 1998), at the Porcupine Abyssal Plain (~ 48° 50?N 16° 30?W, 4850 m depth) within the framework of the MAST 3 BENGAL project. This site was known to be subject to seasonality in the input of organic matter to the seafloor. Results are given for each faunal size class in terms of taxonomic structure at the level of phylum, class or order, depending on the taxon, and for the dominant faunal components in terms of density and vertical distribution. For each lipid compound class, results are given in concentration and vertical distribution. The taxonomic structure of each size class did not change within the study period. Total meiofaunal and macrofaunal densities were particularly high, probably reflecting the high quantity and quality of organic matter inputs to the site. The dominant components of the two size classes presented different temporal patterns in their responses to changes in their environment. Populations of meiofaunal species, a foraminiferan and an opheliid polychaete, which inhabit the surface or sub-surface of sediment and feed on phytodetritus, responded with a rapid increase in abundance to a pulse of organic input in summer 1996. The macrofaunal polychaetes showed a lagged response to the same event by slowly increasing in density. Other components of the sediment community, that can live deeper in the sediment, moved down the sediment column, in response to 1) the impoverishment and bioturbation of the surface layer, and 2) the downward mixing of organic matter in the sediment by larger organisms. In this study, different temporal patterns were demonstrated for the first time in different size classes of the sediment community, and in the biological and environmental parameters that were studied simultaneously. JF - Progress in Oceanography VL - 50 KW - MEIOFAUNA KW - MACROFAUNA KW - NORTHEAST ATLANTIC OCEAN KW - POLYCHAETES KW - SEDIMENT CHEMISTRY KW - BIOLOGY SN - 0079-6611 TI - Temporal patterns among meiofauna and macrofauna taxa related to changes in sediment geochemistry at an abyssal NE Atlantic site SP - 303 AV - none EP - 324 ER - TY - GEN ID - soton417439 UR - https://eprints.soton.ac.uk/417439/ A1 - Gallego, Alejandro A1 - O'Hara Murray, Rory A1 - Berx, Barbara A1 - Turrell, William R. A1 - Beegle-Krause, C. J. A1 - Inall, Mark A1 - Sherwin, Toby A1 - Siddorn, John A1 - Wakelin, Sarah A1 - Vlasenko, Vasyl A1 - Hole, Lars R. A1 - Dagestad, Knut Frode A1 - Rees, John A1 - Short, Lucy A1 - Rønningen, Petter A1 - Main, Charlotte E. A1 - Legrand, Sebastien A1 - Gutierrez, Tony A1 - Witte, Ursula A1 - Mulanaphy, Nicole Y1 - 2018/02/01/ N2 -

As oil reserves in established basins become depleted, exploration and production moves towards relatively unexploited areas, such as deep waters off the continental shelf. The Faroe-Shetland Channel (FSC, NE Atlantic) and adjacent areas have been subject to increased focus by the oil industry. In addition to extreme depths, metocean conditions in this region characterise an environment with high waves and strong winds, strong currents, complex circulation patterns, sharp density gradients, and large small- and mesoscale variability. These conditions pose operational challenges to oil spill response and question the suitability of current oil spill modelling frameworks (oil spill models and their forcing data) to adequately simulate the behaviour of a potential oil spill in the area. This article reviews the state of knowledge relevant to deepwater oil spill modelling for the FSC area and identifies knowledge gaps and research priorities. Our analysis should be relevant to other areas of complex oceanography.

KW - Deepwater KW - Faroe-Shetland Channel KW - Modelling KW - Northeast Atlantic KW - Oil spill SN - 0025-326X TI - Current status of deepwater oil spill modelling in the Faroe-Shetland Channel, Northeast Atlantic, and future challenges SP - 484 AV - public EP - 504 ER - TY - RPRT ID - soton302 UR - https://eprints.soton.ac.uk/302/ A1 - German, C.R. Y1 - 1998/// N2 - The principal objective of the cruise was to recover a series of 11 long-term (12 month) current meter and sediment trap moorings deployed in Summer 1997 to monitor the neutrally-buoyant hydrothermal plume overlying the Rainbow hydrothermal field on the Mid-Atlantic Ridge, near 36°15?N. Secondary objectives were to continue CTD investigations of the physical and geochemical evolution of the plume and to attempt box-coring in sedimented areas identified from TOBI sidescan sonar records beneath the dispersing neutrally buoyant plume. Mooring recovery was completely successful for all three of the sediment trap moorings with the exception that one 2-week sample was lost from one of the 5 multi-collector sediment traps deployed. Seven of the eight current meter moorings deployed were also recovered, with 100% data-recovery from the 21 current meters recovered inboard. A total of 35 CTD-nephelometer profile stations were occupied to the North and South of the Rainbow hydrothermal field, together with one background station , east of the MAR. In situ CTD and nephel data were complemented by water sampling for He-3 and CH4 and shipboard analysis of rosette samples for salinity and TDMn. A total of 4 box-cores were attempted at depths of 2400-2600m beneath the neutrally buoyant plume. All four cores were successful yielding core lengths of 43, 30, 18 and 18cm at distances of 2, 5, 12 and 29km downstream from the known hydrothermal vent-field, respectively. PB - Southampton Oceanography Centre, University of Southampton T3 - 20 KW - acronym KW - AMAR KW - Azores Triple Junction KW - cruise 240 1998 KW - CTD observations KW - FLAME 2 KW - hydrothermal activity KW - Mid Atlantic Ridge KW - nephelometer KW - plume dynamics KW - Poseidon KW - Rainbow Hydrothermal Field KW - sediment M1 - project_report TI - FS Poseidon Cruise 240, 19 Jun-10 Jul 1998. The Fluxes at AMAR Experiment: FLAME 2 AV - public EP - 43 ER - TY - RPRT ID - soton311 UR - https://eprints.soton.ac.uk/311/ A1 - German, C.R. Y1 - 1997/// N2 - The principle objectives of the cruise were to study the physical, geochemical and biological dispersion of the neutrally-buoyant hydrothermal plume overlying the Rainbow hydrothermal field on the Mid-Atlantic Ridge, near 36°15'N; to investigate the interacting processes active within the dispersing plume; to better constrain the source of active venting on the seabed; and to quantify the physical, geochemical and biological fluxes to the water column on the segment scale. A secondary objective was to better constrain the source of strong dissolved methane concentrations which had been observed previously in the FAMOUS segment further north. An additional objective, which evolved during the course of the cruise programme, was to investigate the dispersion of vent-larvae through hydrothermal plumes along a section of the MAR extending from the Rainbow area to the previously known Lucky Strike hydrothermal field at 37°17'N. Initially, a series of hydrographic CTD stations were occupied, complete with a lowered Acoustic Doppler Current Profiler (L-ADCP) to provide instantaneous measurements of prevailing current directions with depth in the water column. This was coupled with a suite of deep-tow CTD tow-yo sections using the hydrothermal plume instrument BRIDGET. This preliminary data set yielded an understanding of the nature of plume dispersion which was then utilised to target further water column sampling using a combination of further CTD hydrocasts for water column samples, in situ filtration of particles for mineralogical, geochemical and microbiological investigations and RMT 1+8 Net trawls for biology. The strategy was largely successful and the neutrally buoyant plume, which was revealed to be dispersing under topographic control, was traced to a distance of greater than 50km down-stream. As the programme progressed a grid of closely spaced (0.5 nautical miles) orthogonal survey lines were occupied across the suspected site of venting, yielding a resolution of closest approach to the source of better than 200m. Finally at Rainbow, a suite of 8 current-meter moorings were deployed around the vent-site to monitor long-term (>12 month) fluxes of physical parameters including suspended particulate material away from the site of venting. In addition to sampling at Rainbow, 6 CTD stations were occupied in the southern portion of the FAMOUS segment and RMT 1+8 Net Trawls were completed in the Southern AMAR, AMAR, FAMOUS, North FAMOUS and Lucky Strike segments as well as in the non-transform discontinuity (NTD) offset immediately to the south of the Lucky Strike segment. PB - Southampton Oceanography Centre, University of Southampton T3 - 10 KW - AMAR KW - azores triple junction KW - biogeochemistry KW - BRIDGET KW - cruise 228 1997 KW - CTD observations KW - discovery KW - FAMOUS KW - FLAME KW - hydrothermal activity KW - hydrothermal field KW - hydrothermal flow KW - L-ADCP KW - lucky strike KW - mid atlantic ridge KW - plume dynamics KW - project KW - rainbow KW - RMT M1 - project_report TI - RRS Discovery Cruise 228, 21 May-28 Jun 1997. The Fluxes at AMAR Experiment: FLAME AV - public EP - 96 ER - TY - JOUR ID - soton63300 UR - https://eprints.soton.ac.uk/63300/ IS - 3-4 A1 - German, C.R. A1 - Bennett, S.A. A1 - Connelly, D.P. A1 - Evans, A.J. A1 - Murton, B.J. A1 - Parson, L.M. A1 - Prien, R.D. A1 - Ramirez-Llodra, E. A1 - Jakuba, M. A1 - Shank, T.M. A1 - Yoerger, D.R. A1 - Baker, E.T. A1 - Walker, S.L. A1 - Nakamura, K. Y1 - 2008/09/15/ N2 - We report results from an investigation of the geologic processes controlling hydrothermal activity along the previously-unstudied southern Mid-Atlantic Ridge (3?7°S). Our study employed the NOC (UK) deep-tow sidescan sonar instrument, TOBI, in concert with the WHOI (USA) autonomous underwater vehicle, ABE, to collect information concerning hydrothermal plume distributions in the water column co-registered with geologic investigations of the underlying seafloor. Two areas of high-temperature hydrothermal venting were identified. The first was situated in a non-transform discontinuity (NTD) between two adjacent second-order ridge-segments near 4°02?S, distant from any neovolcanic activity. This geologic setting is very similar to that of the ultramafic-hosted and tectonically-controlled Rainbow vent-site on the northern Mid-Atlantic Ridge. The second site was located at 4°48?S at the axial-summit centre of a second-order ridge-segment. There, high-temperature venting is hosted in an 18 km2 area of young lava flows which in some cases are observed to have flowed over and engulfed pre-existing chemosynthetic vent-fauna. In both appearance and extent, these lava flows are directly reminiscent of those emplaced in Winter 2005?06 at the East Pacific Rise, 9°50?N and reference to global seismic catalogues reveals that a swarm of large (M 4.6?5.6) seismic events was centred on the 5°S segment over a 24 h period in late June 2002, perhaps indicating the precise timing of this volcanic eruptive episode. Temperature measurements at one of the vents found directly adjacent to the fresh lava flows at 5°S MAR (Turtle Pits) have subsequently revealed vent-fluids that are actively phase separating under conditions very close to the Critical Point for seawater, at 3000 m depth and 407 °C: the hottest vent-fluids yet reported from anywhere along the global ridge crest.
JF - Earth and Planetary Science Letters VL - 273 KW - hydrothermal activity KW - South Atlantic KW - Mid-Atlantic Ridge KW - volcanism KW - tectonics SN - 0012-821X TI - Hydrothermal activity on the southern Mid-Atlantic Ridge: Tectonically- and volcanically-controlled venting at 4?5°S SP - 332 AV - none EP - 344 ER - TY - RPRT ID - soton41274 UR - https://eprints.soton.ac.uk/41274/ A1 - German, C.R. A1 - Parson, L.M. Y1 - 2006/// N2 - The principal objective of this cruise was to identify the first site or sites of high temperature hydrothermal venting anywhere on the southern Mid-Atlantic Ridge, to characterize their geological setting, preliminary chemical nature and to identify, where possible, the nature of any vent-endemic species that might inhabit such vents to investigate whether this ridge system might represent a new biogeographic province. Initially we used the TOBI deep-tow sidescan system equipped with a CTD system and optical backscatter sensors, together with Miniature Autonomous Plume Recorders (MAPRs) to identify two new sites in which diagnostic chemically- and particle-laden plumes indicated the presence of high-temperature hydrothermal venting. Subsequently, we used the ABE autonomous underwater vehicle to (1) locate the core of one of these hydrothermal plumes, (2) obtain a detailed map of the underlying seafloor and (3) photograph three discrete hydrothermal sites (2 black-smoker systems, 1 diffuse-flow) and their associated ecosystems. A series of CTD stations were occupied for water column investigations and a number of rock-coring and dredging stations were also undertaken to provide groundtruthing of sidescan sonar images of the Mid-Atlantic Ridge seafloor. PB - National Oceanography Centre T3 - 6 KW - ABE KW - ATLSE KW - BRIDGET KW - Charles Darwin KW - Cruise 169 2005 KW - CTD KW - EM-12 KW - hydrothermal activity KW - MAPRs KW - Mid-Atlantic Ridge KW - Red Lion KW - South Atlantic Ocean KW - TOBI KW - Turtle Pits KW - vent sites KW - Wideawake M1 - project_report TI - RRS "Charles Darwin" Cruise 169, 17 Feb-19 Mar 2005. Hydrothermal exploration of the southern Mid-Atlantic Ridge AV - public EP - 92 ER - TY - JOUR ID - soton41426 UR - https://eprints.soton.ac.uk/41426/ A1 - Gerringa, L.J.A. A1 - Rijkenberg, M.J.A. A1 - Timmermans, K.R. A1 - Buma, A.G.J. Y1 - 2004/// N2 - Hydrogen peroxide (H2O2) was measured in marine surface waters of the eastern Atlantic Ocean between 25degreesN and 25degreesS. H2O2 concentrations decreased from 80 nM in the north to 20 nM in the south, in agreement with earlier observations. A diel cycle of H2O2 production as a function of sunlight in surface waters was followed twice whilst the ship steamed southward. Around 23degreesN a distinct diel cycle could be measured which correlated well with irradiance conditions. The wavelength dependency of H2O2 formation was studied near the equator. For 16 hours, water samples were incubated with wavelength hands of the solar spectrum, i.e. visible (VIS: 400-700 nm), VIS and ultraviolet A radiation (UVAR: 320-400 nm) and VIS, UVAR and ultraviolet B radiation (UVBR: 280-320 rim). A significant relationship was found between wavelength band and the production of H2O2. In addition, a clear positive relationship between intensity and production was found. UVAR was 6.5 times more efficient than VIS in producing 1 nM of H2O2, whereas UVBR was 228 times more efficient than VIS. When these data were weighted with respect to the energy of the solar spectrum at zenith hour, 28% of the H2O2 was formed by VIS, 23% was formed by UVAR and 48% was formed by UVBR. Considering the strong attenuation of UVBR in marine waters as compared with UVAR and VIS radiation, the role of UVAR deeper in the water column is recognised. Furthermore results of this research emphasise the importance of VIS radiation in the formation of H2O2. JF - Journal of Sea Research VL - 51 KW - hydrogen peroxide KW - organic peroxides KW - Atlantic Ocean KW - UV radiation KW - photochemical production SN - 1385-1101 TI - The influence of solar ultraviolet radiation on the photochemical production of H2O2 in the equatorial Atlantic Ocean SP - 3 AV - none EP - 10 ER - TY - JOUR ID - soton8968 UR - https://eprints.soton.ac.uk/8968/ IS - 3/4 A1 - Gibb, S.W. A1 - Barlow, R.G. A1 - Cummings, D.G. A1 - Rees, N.W. A1 - Trees, C.C. A1 - Holligan, P. A1 - Suggett, D. Y1 - 2000/// N2 - We present an overview of the spatial distributions of phytoplankton pigments along transects between the UK and the Falkland Islands. These studies, undertaken as a component of the UK Atlantic Meridional Transect (AMT) programme, provided the first post-launch validation data for the NASA SeaWiFS satellite. Pigment data are used to characterise basin-scale variations in phytoplankton biomass and community composition over 100° of latitude, and to compliment the definition of hydrographic oceanic provinces. A summary of the key pigment characteristics of each province is presented.
Concentrations of total chlorophyll a (totCHLa = chlorophyll a, CHLa + divinyl CHLa, dvCHLa) were greatest in high latitude temperate waters (>37°N and >35°S), and in the Canary Current Upwelling system. In these regions, the total carotenoid (totCAR) budget was dominated by photosynthetic carotenoids (PSCs). High accessory pigment diversity was observed of which fucoxanthin (FUC), 19'?hexanoyloxyfucoxanthin (HEX), and diadinoxanthin (DIAD) were most abundant, indicating proliferation of large eukaryotes and nanoflagellates. In contrast, tropical and sub-tropical waters exhibited concentrations of totCHLa below 500 ng l?1, with the North Atlantic Sub-tropical East gyre (NASE, 26.7?35°N), South Equatorial Current (SeqC, 7?14.6°S) and South Atlantic tropical Gyre (SATG, 14.6?26°S) characterised by totCHLa of <100 ng?1. These waters exhibited relatively limited pigment diversity, and the totCAR budget was dominated by photoprotecting pigments (PPCs) of which zeaxanthin (ZEA), a marker of prokaryotes (cyanobacteria and prochlorophytes), was most abundant. DvCHLa, a marker of prochlorophytes was detected in waters at temperatures >15°C, and between the extremes of 48°N and 42°S. DvCHLa accounted for up to two-thirds of totCHLa in oligotrophic provinces demonstrating the importance of prochlorophytes to oceanic biomass.
Overall, HEX was the dominant PSC, contributing up to 75% of totCAR. HEX always represented >2% of totCAR and was the only truly ubiquitous carotenoid. Since HEX is a chemotaxonomic marker of prymnesiophytes, this observation reflects the truly cosmopolitan distribution of this algal class. ZEA was found to be the most abundant PPC contributing more than one third of the total carotenoid budget in each transect.
Greatest seasonality was observed in highly productive waters at high latitudes and in shallow continental shelf waters and attributed to proliferation of large eukaryotes during spring. Concentrations of the prokaryote pigments (ZEA + dvCHLa) also exhibited some seasonality, with elevated concentrations throughout most of the transect during Northern Hemisphere spring. JF - Progress in Oceanography VL - 45 KW - AMT KW - ATLANTIC OCEAN KW - ATLANTIC MERIDIONAL TRANSECT KW - RESEARCH PROGRAMMES KW - PHYTOPLANKTON KW - PIGMENTS KW - SEAWIFS KW - OPTICAL PROPERTIES KW - REMOTE SENSING SN - 0079-6611 TI - Surface phytoplankton pigment distributions in the Atlantic Ocean: an assessment of basin scale variability between 50N and 50S SP - 339 AV - none EP - 368 ER - TY - JOUR ID - soton37838 UR - https://eprints.soton.ac.uk/37838/ IS - 1 A1 - Gibbs, S.J. A1 - Shackleton, N.J. A1 - Young, J.R. Y1 - 2004/// N2 - Downcore cyclic variation in high-resolution nannofossil abundance records from mid-Pliocene equatorial Atlantic ODP Sites 662 and 926 demonstrate the direct response by several Pliocene taxa (notably Discoaster, Sphenolithus and Florisphaera profunda) to orbitally forced climatic variation. In particular, these records display strong obliquity and precessional signals reflecting primarily high latitude, Southern hemisphere changes influencing upwelling intensity and local low-latitude, insolation-driven climatic changes (via the productivity and/or turbidity influence of Amazon-sourced terrigenous material) at Sites 622 and 926 respectively.
In seasonal studies of coccolithophorid assemblages, only part of the variation observed can be explained by abiotic processes, so it is perhaps not surprising that in this study few Pliocene nannofossil taxa demonstrate significant correlations with each other or with physical environmental parameters. Only some variance in nannofossil abundances can be explained by the primary controls of temperature and productivity. The rest is attributed to nonlinear responses to climatic changes; biotic processes such as grazing, predation, viral infection and competition, and/or, abiotic factors for which there is no readily available proxy (e.g. salinity). The lack of strong, consistent intra- and inter-relationships of the nannoflora and the environment reflects an ecologically complex, differentiated original community producing a complex integrated signal transmitted into the fossil record. JF - Marine Micropaleontology VL - 51 KW - pliocene KW - central atlantic KW - calcareous nannofossils KW - biological cycles KW - environmental parameters SN - 0377-8398 TI - Orbitally forced climate signals in mid-Pliocene nannofossil assemblages SP - 39 AV - none EP - 56 ER - TY - JOUR ID - soton37839 UR - https://eprints.soton.ac.uk/37839/ IS - 1-2 A1 - Gibbs, Samantha J. A1 - Young, Jeremy R. A1 - Bralower, Timothy J. A1 - Shackleton, Nicholas J. Y1 - 2005/02/11/ N2 - The mid-Pliocene was an interval of subtle reorganisation within the nannoplankton community, including the prominent and biostratigraphically important last occurrences of Sphenolithus abies and Reticulofenestra pseudoumbilicus. The transition is part of the Pliocene to Recent ?attrition? of nannofossil species that resulted from changes in the distribution of trophic resources, and deep-water and surface-water current systems, likely associated with the initiation of Northern Hemisphere glaciation.
The extinctions of Sphenolithus abies and Reticulofenestra pseudoumbilicus were analysed in detail at ODP Sites 659, 662, and 926 in the equatorial and subequatorial Atlantic. These taxa show significantly different patterns of duration and timing of decline based on high-resolution abundance records and calibration with oxygen isotope stratigraphy. The initiation of abundance decline between 3.71 and 3.67 Ma and the extinction of S. abies between 3.56 and 3.52 Ma are diachronous. This extinction may have been a response to the intensification of glacial intervals at this time. In contrast, the last occurrence of R. pseudoumbilicus at 3.81?3.82 Ma appears to be a valid example of biostratigraphic (although not necessarily biological) synchrony in the fossil record. Direct environmental forcing is not attributable for the extinction of R. pseudoumbilicus; however, indirect physical and/or biological environmental stress may explain the observed patterns. JF - Palaeogeography, Palaeoclimatology, Palaeoecology VL - 217 KW - pliocene KW - central atlantic KW - calcareous nannofossils KW - biostratigraphy KW - evolution KW - extinction SN - 0031-0182 TI - Nannofossil evolutionary events in the mid-Pliocene: an assessment of the degree of synchrony in the extinctions of Reticulofenestra pseudoumbilicus and Sphenolithus abies SP - 155 AV - none EP - 172 ER - TY - JOUR ID - soton361693 UR - https://eprints.soton.ac.uk/361693/ IS - 4 A1 - Gledhill, Martha A1 - Achterberg, Eric P. A1 - Honey, David J. A1 - Nielsdottir, Maria C. A1 - Rijkenberg, Micha J.A. Y1 - 2013/12// N2 - Concentrations of heme b, the iron-containing component of b-type hemoproteins, ranged from?<?0.4 to 5.3 pM with an average of 1.18?±?0.8 pM (± 1?; n?=?86) in the Iceland Basin (IB), from?<?0.4 to 19.1 pM with an average of 2.24?±?1.67 pM (n?=?269) in the tropical northeast Atlantic (TNA) and from 0.6 to 21 pM with an average of 5.1?±?4.8 pM (n?=?34) in the Scotia Sea (SS). Heme b concentrations were enhanced in the photic zone and decreased with depth. Heme b concentrations correlated positively with chlorophyll a (chl a) in the TNA (r?=?0.41, p?<?0.01, n?=?269). Heme b did not correlate with chl a in the IB or SS. In the IB and SS, stations with high-chlorophyll and low-nutrient (Fe and/or Si) concentrations exhibited low heme b concentrations relative to particulate organic carbon (< 0.1??mol?mol?1), and high chl a:heme b ratios (> 500). High chl a:heme b ratios resulted from relative decreases in heme b, suggesting proteins such as cytochrome b6f, the core complex of photosystem II, and eukaryotic nitrate reductase were depleted relative to proteins containing chlorophyll such as the eukaryotic light-harvesting antenna. Relative variations in heme b, particulate organic carbon, and chl a can thus be indicative of a physiological response of the phytoplankton community to the prevailing growth conditions, within the context of large-scale changes in phytoplankton community composition. JF - Global Biogeochemical Cycles VL - 27 KW - iron KW - phytoplankton KW - physiology KW - nutrients KW - biogenic particulate material KW - atlantic ocean SN - 0886-6236 TI - Distributions of particulate Heme b in the Atlantic and Southern Oceans - implications for electron transport in phytoplankton SP - 1072 AV - public EP - 1082 ER - TY - JOUR ID - soton1361 UR - https://eprints.soton.ac.uk/1361/ IS - 1 A1 - Glover, A. A1 - Paterson, G. A1 - Bett, B. A1 - Gage, J. A1 - Sibuet, M. A1 - Sheader, M. A1 - Hawkins, L. Y1 - 2001/// N2 - Polychaete abundance and diversity patterns from the Madeira Abyssal Plain (MAP) were studied together with data from three other sites on the northeastern Atlantic abyssal plains. Polychaete abundance at MAP was significantly lower than at any of the other sites, including those lying under comparable productivity regimes. Analysis of diversity, using rarefaction and species counts per unit area, suggests that MAP is extremely species poor and shows dominance by a few common species. The MAP site is characterised by a superficial layer of turbidite sediment, and the hypothesis is put forward that the unusual sediment characteristics at MAP have affected macrofaunal abundance over a vast area (>2000 km2). Analysis of species composition indicates that the MAP site is not faunistically unique; rather it contains a high proportion of widespread, abundant, cosmopolitan species. We suggest that these are the opportunists of the abyssal benthic habitat. Differences in abundance between the other abyssal sites are the result of both productivity and local environmental conditions. Equitability at the other north Atlantic sites is not affected by productivity, although the actual number of species per unit area is affected, showing a south?north gradient. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 48 KW - Deep sea KW - Polychaeta KW - Productivity KW - Turbidite KW - Biodiversity KW - Biogeography KW - Northeast Atlantic KW - Madeira Abyssal Plain SN - 0967-0637 TI - Patterns in polychaete abundance and diversity from the Madeira Abyssal Plain, northeast Atlantic SP - 217 AV - none EP - 236 ER - TY - JOUR ID - soton448627 UR - https://eprints.soton.ac.uk/448627/ A1 - González-santana, David A1 - González-dávila, Melchor A1 - Lohan, Maeve C. A1 - Artigue, Lise A1 - Planquette, Hélène A1 - Sarthou, Géraldine A1 - Tagliabue, Alessandro A1 - Santana-casiano, J. Magdalena Y1 - 2021/03/15/ N2 - One of the recently recognized main sources of iron to the deep ocean inventory is the hydrothermal activity associated with mid-ocean ridges. Little is known about the oxidation kinetics of iron(II) within these environments, especially the dependence on physico-chemical parameters such as temperature (T), pH, particle size-fractionation and the effect of organic matter.

Following sample collection during the GA13 section cruise, the iron(II) oxidation at six hydrothermal vent sites (Menez Gwen, Lucky Strike, Rainbow, Lost City, Broken Spur and TAG) along the Mid-Atlantic Ridge were investigated, revealing high variability. The Fe(II) oxidation rate constant analysis from multiple stations at two sites (Rainbow and TAG), revealed that factors, other than T and pH, controlled the oxidation process. Experiments on the effect of particle size-fractionation and organic matter at different pH showed that the presence of organic ligands and colloidal size particles delayed the oxidation process, while not affecting the overall pH dependency.

Extending our analysis to the broader relationship between the Fe(II) oxidation rate constants across a range of temperatures (between 2 and 25?°C) and pH (between 7 and 8) on a set of selected hydrothermal samples allowed us to derive a multiparametric equation to model the iron(II) oxidation rate constants in the ocean. This equation covers a larger range of temperatures than previous published equations, improving its applicability for global biogeochemical models. JF - Geochimica et Cosmochimica Acta VL - 297 KW - Fe(II) half-life time KW - Fe(II) oxidation kinetics KW - Hydrothermal KW - Kinetic equation KW - Mid Atlantic Ridge SN - 0016-7037 TI - Variability in iron (II) oxidation kinetics across diverse hydrothermal sites on the northern Mid Atlantic Ridge SP - 143 AV - public EP - 157 ER - TY - JOUR ID - soton193821 UR - https://eprints.soton.ac.uk/193821/ IS - 3 A1 - Good, P. A1 - Caesar, J. A1 - Bernie, D. A1 - Lowe, J.A. A1 - van der Linden, P. A1 - Gosling, S.N. A1 - Warren, R. A1 - Arnell, N.W. A1 - Smith, S. A1 - Bamber, J. A1 - Payne, T. A1 - Laxon, S. A1 - Srokosz, M. A1 - Sitch, S. A1 - Gedney, N. A1 - Harris, G. A1 - Hewitt, H. A1 - Jackson, L. A1 - Jones, C.D. A1 - O'Connor, F. A1 - Ridley, J. A1 - Vellinga, M. A1 - Halloran, P. A1 - McNeall, D. Y1 - 2011/06// N2 - This article reviews some of the major lines of recent scientific progress relevant to the choice of global climate policy targets, focusing on changes in understanding since publication of the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4). Developments are highlighted in the following major climate system components: ice sheets; sea ice; the Atlantic Meridional Overturning Circulation; tropical forests; and accelerated carbon release from permafrost and ocean hydrates. The most significant developments in each component are identified by synthesizing input from multiple experts from each field. Overall, while large uncertainties remain in all fields, some substantial progress in understanding is revealed. JF - Progress in Physical Geography VL - 35 KW - Atlantic Meridional Overturning Circulation (AMOC) KW - climate change KW - global climate KW - ice sheets KW - Intergovernmental Panel on Climate Change (IPCC) KW - sea ice KW - tropical forest SN - 0309-1333 TI - A review of recent developments in climate change science. Part I: Understanding of future change in the large-scale climate system SP - 281 AV - none EP - 296 ER - TY - JOUR ID - soton420407 UR - https://eprints.soton.ac.uk/420407/ IS - 1 A1 - Good, Peter A1 - Bamber, Jonathan A1 - Halladay, Kate A1 - Harper, Anna B. A1 - Jackson, Laura C. A1 - Kay, Gillian A1 - Kruijt, Bart A1 - Lowe, Jason A. A1 - Phillips, Oliver L. A1 - Ridley, Jeff A1 - Srokosz, Meric A1 - Turley, Carol A1 - Williamson, Phillip Y1 - 2018/02// N2 -

This article reviews recent scientific progress, relating to four major systems that could exhibit threshold behaviour: ice sheets, the Atlantic meridional overturning circulation (AMOC), tropical forests and ecosystem responses to ocean acidification. The focus is on advances since the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5). The most significant developments in each component are identified by synthesizing input from multiple experts from each field. For ice sheets, some degree of irreversible loss (timescales of millennia) of part of the West Antarctic Ice Sheet (WAIS) may have already begun, but the rate and eventual magnitude of this irreversible loss is uncertain. The observed AMOC overturning has decreased from 2004?2014, but it is unclear at this stage whether this is forced or is internal variability. New evidence from experimental and natural droughts has given greater confidence that tropical forests are adversely affected by drought. The ecological and socio-economic impacts of ocean acidification are expected to greatly increase over the range from today?s annual value of around 400, up to 650 ppm CO2 in the atmosphere (reached around 2070 under RCP8.5), with the rapid development of aragonite undersaturation at high latitudes affecting calcifying organisms. Tropical coral reefs are vulnerable to the interaction of ocean acidification and temperature rise, and the rapidity of those changes, with severe losses and risks to survival at 2 °C warming above pre-industrial levels. Across the four systems studied, however, quantitative evidence for a difference in risk between 1.5 and 2 °C warming above pre-industrial levels is limited.

JF - Progress in Physical Geography VL - 42 KW - Atlantic meridional overturning circulation KW - climate change KW - ice sheets KW - ocean acidification KW - thresholds KW - tropical forests SN - 0309-1333 TI - Recent progress in understanding climate thresholds: Ice sheets, the Atlantic meridional overturning circulation, tropical forests and responses to ocean acidification SP - 24 AV - none EP - 60 ER - TY - JOUR ID - soton360967 UR - https://eprints.soton.ac.uk/360967/ A1 - Gooday, A.J. A1 - Alt, C.H.S. A1 - Jones, D.O.B. A1 - Shale, D. A1 - Marsden, K. A1 - Brasier, M.D. Y1 - 2013/12/15/ N2 - The large (?1 cm diameter) miliolid foraminifera Discospirina tenuissima (Carpenter and Jeffreys, 1870) is common at four sites (NW, NE, SW, and SE), located on either side of the Mid-Atlantic Ridge to the north (54°N) and south (49°N) of the Charlie?Gibbs Fracture Zone. The white discoidal tests of this epifaunal species were visible in video surveys of flat and gently (10°) sloping, sediment-covered areas of seafloor (replicate 500-m-long transects, 1000 m2 surface area) obtained using the Remote Operated Vehicle Isis. Average densities varied from 0.07 (SE site) to 1.12 (NW) ind m?2 for sloped transects and 0.02 (NW) to 1.75 (SW) ind m?2 for flat transects. Considerable variation was also evident between individual transects (0?2.25 ind m?2). The tests displayed no consistent dispersion pattern; both significantly random and clumped patterns were observed, in some cases within a single site. Isis was also used to make detailed in situ observations of D. tenuissima and to collect individual specimens. The delicate test margin sometimes exhibited angular notches and other signs of damage, presumably a result of megafaunal activity; in some cases the damage had been repaired. Specimens perforated by a large central hole occurred at the SE site. Smaller sessile organisms, including agglutinated foraminifera and occasional brachiopods, use D. tenuissima tests as a substratum for attachment. In all areas, some tests were surrounded by a ring of sediment, presumably surface material collected by pseudopodia. We interpret these features as being comparable to the feeding cysts created by other foraminiferal species. They were particularly common at the SE site, where one or two abandoned rings indicated that some tests had moved distances of several centimetres across the seafloor. Most previous records of D. tenuissima are from well-oxygenated sites in the NE Atlantic. We provide the first records from the Indian Ocean. Here, this species occurs at bathyal depths in the northwest (1980 m) and northeast (938 m) Arabian Sea, where bottom-water oxygen concentrations are depressed. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 98 KW - mid-atlantic ridge KW - benthos KW - miliolid KW - phytodetritus KW - north atlantic ocean KW - indian ocean SN - 0967-0645 TI - The ecology and biogeography of Discospirina tenuissima (Foraminifera) in the Atlantic and Indian Oceans SP - 301 AV - none EP - 314 ER - TY - JOUR ID - soton7958 UR - https://eprints.soton.ac.uk/7958/ IS - 1-4 A1 - Gooday, A.J. A1 - Alve, E. Y1 - 2001/// JF - Progress in Oceanography VL - 50 KW - Atlantic KW - NE Atlantic KW - Porcupine Abyssal Plain KW - Oslofjord KW - Lyngdalsfjord SN - 0079-6611 TI - Morphological and ecological parallels between sublittoral and abyssal foraminiferal species in the NE Atlantic: a comparison of Stainforthia fusiformis and Stainforthia sp SP - 261 AV - none EP - 283 ER - TY - JOUR ID - soton189479 UR - https://eprints.soton.ac.uk/189479/ IS - 23-24 A1 - Gooday, A.J. A1 - Aranda da Silva, A. A1 - Pawlowski, J. Y1 - 2011/12/01/ N2 - Xenophyophores are abundant on a terrace of the lower Nazaré Canyon (4300 m water depth) on the Portuguese margin. Here, the most abundant species, Reticulammina cerebreformis sp. nov., occurs in densities of up to 21 individuals/m2. This large species has a soft, friable hemispherical test up to 10 cm in diameter consisting of curved, sinuous plates (lamellae) that branch and anastomose. The plates are separated by deep furrows and other depressions to form a distinctive ?brain-like? structure. The outer test layer is thin, weakly cemented and is dominated by fine sediment particles; the internal xenophyae include a higher proportion of larger mineral grains. The second new species at the 4300-m site, Nazareammina tenera gen. et sp. nov., is much less common. The test is basically plate-like, but towards the interior it is perforated by oval spaces, which typically merge into complex system of bar-like features, sometimes with irregular excrescences. The granellare system (cell body and its organic envelope) is packed with tiny mineral grains of various sizes and shapes, including titanium-bearing particles. Also common at this deep site are clusters, with a maximum diameter up to 10 cm or occasionally more, of irregular tubes belonging to Aschemonella ramuliformis Brady 1884, a species previously known mainly from isolated tubes. Rather than being single individuals, these clusters comprise a large number of separate branched tubes. Finally, Syringammina fragillissima Brady 1883, a well-known species that is widely distributed on the NW European margin, occurred on steep sediment-covered slopes at a shallower (1555 m water depth) site in the upper canyon. Almost complete SSU rDNA gene sequences obtained from A. ramuliformis and R. cerebreformis confirm that these previous termxenophyophoresnext term are foraminifera. Together with two previously sequenced xenophophores (Shinkaia lindsayi Lecroq, Gooday, Tsuchiya, Pawlowski 2009 and Syringammina corbicula Richardson 2001), and the foraminiferan Rhizammina algaeformis, they constitute a clade within the radiation of monothalamous foraminifera. In situ photographs of R. cerebreformis and A. ramuliformis reveal no evidence of pseudopodia deployed onto the sediment surface. Instead, these species probably trap sediment within their complex, folded test surface (R. cerebreformis) or intercept suspended particles (A. ramuliformis). JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 58 KW - Benthos KW - Deep sea KW - Megafauna KW - Protists KW - Submarine canyons KW - Taxonomy KW - Atlantic KW - NE Atlantic KW - Portuguese margin SN - 0967-0645 TI - Xenophyophores (Rhizaria, Foraminifera) from the Nazaré Canyon (Portuguese margin, NE Atlantic) SP - 2401 AV - none EP - 2419 ER - TY - JOUR ID - soton1408 UR - https://eprints.soton.ac.uk/1408/ IS - 1 A1 - Gooday, A.J. A1 - Hori, S. A1 - Todo, Y. A1 - Okamoto, T. A1 - Kitazato, H. A1 - Sabbatini, A. Y1 - 2004/01// N2 - Delicate foraminiferans with test walls that are either agglutinated (Order Astrorhizida, Families Saccamminidae and Psammosphaeridae) or composed of organic material (Order Allogromiida) are often an important element of deep-sea benthic assemblages. Many species have soft, flexible walls and, except for a few allogromiids, are monothalamous (single-chambered). We examined quantitative multicorer samples from abyssal (4263?5570 m) water depths in the North and western Equatorial Pacific and a qualitative sample from a hadal site (7800 m water depth) in the Atacama Trench, SE Pacific. Soft-walled foraminiferans made up 29?42% of all complete, 'live' (rose Bengal stained) foraminiferans in the>32 µm fractions (0?1 cm sediment layer) of the North Pacific samples and 63% in the western Equatorial Pacific sample. They included the following morphotypes: (i) organic-walled allogromiids with one or occasionally two apertures; (ii) Nodellum- and Resigella-like forms in which the organic wall is generally brownish in colour and the test sometimes divided into more or less well-defined chambers by constrictions or partitions; (iii) flask-like agglutinated saccamminids with one aperture; (iv) oval saccamminids with two apertures; (v) agglutinated spheres which lack obvious apertures (psammosphaerids). In addition, numerous isolated spherical chambers, believed to be fragments derived from much larger komokiacean foraminiferans, were present in some samples and easily confused with saccamminids. At each Pacific station, we recognised 26?55 morphologically distinct forms (morphospecies) in addition to numerous 'indeterminate' specimens that could not be categorised on the basis of morphological criteria. A comparison of the Pacific assemblages with existing data on monothalamous assemblages from abyssal and bathyal depths in the Atlantic and Indian Oceans (>63 µm fraction) suggests that some morphospecies have wide geographical and bathymetric distributions. These wide-ranging morphospecies could provide good targets for future molecular-level studies addressing species differentiation among soft-shelled, monothalamous deep-sea foraminiferans. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 51 KW - Abyssal KW - Allogromiids KW - North and Equatorial Pacific KW - Northeast Atlantic KW - Arabian Sea SN - 0967-0637 TI - Soft-walled, monothalamous benthic foraminiferans in the Pacific, Indian and Atlantic Oceans: aspects of biodiversity and biogeography SP - 33 AV - none EP - 53 ER - TY - JOUR ID - soton352177 UR - https://eprints.soton.ac.uk/352177/ IS - 5-6 A1 - Gooday, Andrew J. A1 - Rothe, Nina A1 - Pearce, Richard B. Y1 - 2013/04// N2 - Based on sediment samples from the Mid-Atlantic Ridge (MAR; 49?54°N, 2508?2772 m water depth) we redescribe Hospitella fulva Rhumbler, 1911, an organic-walled foraminiferal species that inhabits the empty shells of planktonic foraminifera and has not been reported since its initial description more than 100 years ago. This poorly known species is characterized by a series of more or less globular ?pseudo-chambers? joined by tubular stolons and with an organic, brownish-orange, somewhat brittle test wall. It is probably related to Placopsilinella aurantiaca Earland, 1934, a species that is commonly attached to the external surface of planktonic foraminiferal shells at our MAR sites. A second inhabiting foramininferan, which we describe as Incola inculta gen. & sp. nov., is distinguished from H. fulva by the very thin and flexible organic test wall and the distinct tubular to somewhat conical agglutinated structure, which extends above the surface of the host shell and terminates in an aperture. A large number of xanthosomes (waste products) are distributed throughout the cell body of the new species. These and other inhabitants of planktonic foraminiferal shells make an important contribution to benthic foraminiferal assemblages on the bathyal MAR. JF - Marine Biology Research VL - 9 KW - North Atlantic KW - ECOMAR KW - MAR-ECO KW - deep-sea protists KW - organic-walled foraminifera SN - 1745-1000 TI - New and poorly known benthic foraminifera (Protista, Rhizaria) inhabiting the shells of planktonic foraminifera on the bathyal Mid-Atlantic Ridge SP - 447 AV - none EP - 461 ER - TY - JOUR ID - soton8857 UR - https://eprints.soton.ac.uk/8857/ IS - 1/2 A1 - Gracia, E. A1 - Charlou, J.L. A1 - Radford-Knoery, J. A1 - Parson, L.M. Y1 - 2000/// N2 - Ten contiguous non-transform offsets (NTOs) along the Mid-Atlantic Ridge (MAR) south of the Azores (between 38°N and 35°40?N) have been studied in detail using swath bathymetric, acoustic backscatter and deep-tow high-resolution sidescan sonar (TOBI) data. In contrast with discontinuities studied elsewhere at slow-spreading ridges, these left-lateral NTOs are consistently broader and larger, with complex structural fabrics accommodating the offset. They are characterized by a range of elevated and faulted massifs detached from their segment flanks, with an irregular acoustic backscatter pattern. Some of these massifs have been explored and sampled recently during dive cruises revealing that they are composed of upper mantle peridotites and lower crustal rocks, and sometimes associated with high-temperature hydrothermal venting. Water column surveys adjacent to these massifs show high CH4 and low TDM (total dissolvable manganese) concentrations, possibly resulting from the process of serpentinization of ultramafic rocks. The correlation between the shallow dome-like shaped massifs and the high concentrations of CH4 (associated with low levels of Mn) is of particular interest to predict the outcrop of ultramafic rocks within the NTOs where no geological data are available. The exposure of the ultramafic massifs within the NTOs is favored by low magmatic supply and low-angle detachment faulting occurring at segment ends. The pervasive fracturing and faulting at these discontinuities favor circulation of hydrothermal fluids and occurrence of high-temperature vent sites. JF - Earth and Planetary Science Letters VL - 177 KW - MID ATLANTIC RIDGE KW - DISCONTINUITIES KW - HYDROTHERMAL ACTIVITY KW - BATHYMETRIC DATA KW - METHANE KW - SIDESCAN SONAR KW - TOBI KW - MANGANESE SN - 0012-821X TI - Non-transform offsets along the Mid-Atlantic Ridge south of the Azores (38N-34N): ultramafic exposures and hosting of hydrothermal vents SP - 89 AV - none EP - 103 ER - TY - JOUR ID - soton380994 UR - https://eprints.soton.ac.uk/380994/ IS - 11 A1 - Grist, J.P. A1 - Josey, S.A. A1 - Jacobs, Z.L. A1 - Marsh, R. A1 - Sinha, B. A1 - Van Sebille, E. Y1 - 2016/06// N2 - Exceptionally low North American temperatures and record-breaking precipitation over the British Isles during winter 2013?2014 were interconnected by anomalous ocean evaporation over the North Atlantic subpolar gyre region (SPG). This evaporation (or oceanic latent heat release) was accompanied by strong sensible heat loss to the atmosphere. The enhanced heat loss over the SPG was caused by a combination of surface westerly winds from the North American continent and northerly winds from the Nordic Seas region that were colder, drier and stronger than normal. A distinctive feature of the air?sea exchange was that the enhanced heat loss spanned the entire width of the SPG, with evaporation anomalies intensifying in the east while sensible heat flux anomalies were slightly stronger upstream in the west. The immediate impact of the strong air?sea fluxes on the ocean?atmosphere system included a reduction in ocean heat content of the SPG and a shift in basin-scale pathways of ocean heat and atmospheric freshwater transport. Atmospheric reanalysis data and the EN4 ocean data set indicate that a longer-term legacy of the winter has been the enhanced formation of a particularly dense mode of Subpolar Mode Water (SPMW)?one of the precursors of North Atlantic Deep Water and thus an important component of the Atlantic Meridional Overturning Circulation. Using particle trajectory analysis, the likely dispersal of newly-formed SPMW is evaluated, providing evidence for the re-emergence of anomalously cold SPMW in early winter 2014/2015. JF - Climate Dynamics VL - 46 KW - North Atlantic Ocean KW - Air?sea fluxes KW - Ocean heat content KW - Subpolar Mode Water KW - Winter 2013?2014 SN - 0930-7575 TI - Extreme air?sea interaction over the North Atlantic subpolar gyre during the winter of 2013?2014 and its sub-surface legacy SP - 4027 AV - public EP - 4045 ER - TY - JOUR ID - soton377995 UR - https://eprints.soton.ac.uk/377995/ A1 - Gunton, Laetitia A1 - Neal, Lenka A1 - Gooday, Andrew A1 - Bett, Brian A1 - Glover, Adrian Y1 - 2015/12// N2 - We examined deep-sea macrofaunal polychaete species assemblage composition, diversity and turnover in the Whittard Canyon system (NE Atlantic; 3500 m water depth). Replicate Megacore samples were collected from three of the canyon branches and one site on the continental slope to the west of the canyon, all at c. 3500 m water depth. A total of 110 polychaete species were recorded. Paramphinome jeffreysii was the most abundant species (2326 ind m-2) followed by Aurospio sp. B (646 ind m-2), Opheliidae sp. A (393 ind m-2), Prionospio sp. I (380 ind m-2), and Ophelina abranchiata (227 ind m-2). Species composition varied significantly across all sites. From west to east, the dominance of Paramphinome jeffreysii increased from 12.9 % on the slope to 39.6 % in the Eastern branch. Ordination of species composition revealed that the Central and Eastern branches were most similar, whereas the Western branch and slope sites were more distinct. High abundances of P. jeffreysii and Opheliidae sp. A characterised the Eastern branch of the canyon and may indicate an opportunistic response to a possible recent input of organic matter inside the canyon. Species diversity indices were higher on the slope than inside the canyon, and the slope site had higher species evenness. Within the canyon, species diversity between branches was broadly similar. Our data does not suggest that the Whittard Canyon makes a substantial contribution to the regional diversity of soft-bottom benthic polychaetes. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 106 KW - Biodiversity KW - Polychaeta KW - Submarine Canyon KW - Deep sea KW - Northeast Atlantic KW - Biogeography SN - 0967-0637 TI - Benthic polychaete diversity patterns and community structure in the Whittard canyon system and adjacent slope (NE Atlantic) SP - 42 AV - public EP - 54 ER - TY - JOUR ID - soton154465 UR - https://eprints.soton.ac.uk/154465/ IS - 9 A1 - Haigh, Ivan A1 - Nicholls, Robert A1 - Wells, Neil Y1 - 2010/05/31/ N2 - A recently extended and spatially rich English Channel sea level dataset has been used to evaluate changes in extreme still water levels throughout the 20th century. Sea level records from 18 tide gauges have been rigorously checked for errors and split into mean sea level, tidal and non-tidal components. These components and the interaction between surge and tide have been analysed separately for significant trends before determining changes in extreme sea level. Mean sea level is rising at 0.8?2.3 mm/year, depending on location. There is a small increase (0.1?0.3 mm/year) in the annual mean high water of astronomical tidal origin, relative to mean sea level, and an increase (0.2?0.6 mm/year) in annual mean tidal range. There is considerable intra- and inter-decadal variability in surge intensity with the strongest intensity in the late 1950s. Storm surges show a statistically significant weak negative correlation to the winter North Atlantic Oscillation index throughout the Channel and a stronger significant positive correlation at the boundary with the southern North Sea. Tide?surge interactions increase eastward along the English Channel, but no significant long-term changes in the distribution of tide?surge interaction are evident. In conclusion, extreme sea levels increased at all of the 18 sites, but at rates not statistically different from that observed in mean sea level. JF - Continental Shelf Research VL - 30 KW - Astronomical tides KW - Mean sea level KW - Storm surges KW - Climate changes KW - Extremes KW - North Atlantic Oscillation KW - English Channel KW - Southern England KW - Northern France SN - 0278-4343 TI - Assessing changes in extreme sea levels: Application to the English Channel, 1900?2006 SP - 1042 AV - none EP - 1055 ER - TY - JOUR ID - soton358312 UR - https://eprints.soton.ac.uk/358312/ IS - 3-4 A1 - Hansell, Dennis A. A1 - Bates, Nicholas R. A1 - Olson, Donald B. Y1 - 2004/01// N2 - The process of nitrogen fixation in the subtropical North Atlantic has received considerable study over the last few decades. The findings have highlighted a large discrepancy in estimates for the locations and rates of nitrogen fixation when results from biological techniques are compared to geochemical techniques. Here, we evaluated the distribution and rates of excess nitrate development in the North Atlantic using World Ocean Circulation Experiment (WOCE) nutrient data. These data indicate that excess nitrate development is largely confined to depths of ?150?400 m in the region of 15?25°N by 25?75°W, an area considerably smaller than that employed by Gruber and Sarmiento [Glob. Biogeochem. Cycles 11 (1997) 235] (10?50°N by 10?90°W) to estimate rates of nitrogen fixation in the North Atlantic. The areally integrated nitrogen fixation rate for the subtropical North Atlantic was 0.045 mol N m?2 year?1, or 62% of the geochemical estimate by Gruber and Sarmiento [Glob. Biogeochem. Cycles 11 (1997) 235]. The regional rate of fixation was 3.1×1011 mol N year?1 (1.5?4.6×1011 mol N year?1 given a 50% uncertainty), similar to rates expected from biological measures of fixation, but only 15% of the areal rate estimated by Gruber and Sarmiento [Glob. Biogeochem. Cycles 11 (1997) 235]. An accurate assessment of the region over which excess nitrate accumulates is critical to the estimate of nitrogen fixation, but remains prone to large uncertainty because of the gaps in spatial coverage. Additional survey work in the North Atlantic must be done to lessen the uncertainty. With this work, we reduce the differences between the biological and geochemical rate estimates, and describe a conceptual model for the location and dynamics of nitrate excess development in the North Atlantic. JF - Marine Chemistry VL - 84 KW - Nitrate KW - Phosphate KW - N/P ratio KW - Subtropical North Atlantic KW - Nitrogen fixation SN - 0304-4203 TI - Excess nitrate and nitrogen fixation in the North Atlantic Ocean SP - 243 AV - none EP - 265 ER - TY - JOUR ID - soton444406 UR - https://eprints.soton.ac.uk/444406/ IS - 9 A1 - Harmon, Nicholas A1 - Rychert, Catherine A1 - Kendall, Mike A1 - Agius, Matthew A1 - Bogiatzis, Petros A1 - Tharimena, Saikiran Y1 - 2020/09/01/ N2 - The oceanic lithosphere is a primary component of the plate tectonic system, yet its evolution and its asthenospheric interaction have rarely been quantified by in situ imaging at slow spreading systems. We use Rayleigh wave tomography from noise and teleseismic surface waves to image the shear wave velocity structure of the oceanic lithosphere?asthenosphere system from 0 to 80 My at the equatorial Mid?Atlantic Ridge using data from the Passive Imaging of the Lithosphere?Asthenosphere Boundary (PI?LAB) experiment. We observe fast lithosphere (VSV > 4.4 km/s) that thickens from 20?30 km near the ridge axis to ~70 km at seafloor >60 My. We observe several punctuated slow velocity anomalies (VSV < 4.1 km/s) in the asthenosphere between 50 and 150 km depth, not necessarily focused beneath the ridge axis. Some of the slow velocity regions are located within 100 km of the ridge axis, but other slow velocity regions are observed at distances > 400 km from the ridge. We observe a high velocity lithospheric downwelling drip beneath 30 My seafloor that extends to 80?130 km depth. The asthenospheric slow velocities likely require partial melt. Although melt is present off axis, the lack of off?axis volcanism suggests the lithosphere acts as a permeability boundary for deeper melts. The punctuated and off?axis character of the asthenospheric anomalies and lithospheric drip suggests small?scale convection is active at a range of seafloor ages. Small?scale convection and/or more complex mantle flow may be aided by the presence of large offset fracture zones and/or the presence of melt and its associated low?viscosities and enhanced buoyancies. JF - Geochemistry, Geophysics, Geosystems VL - 21 KW - Atlantic Ocean KW - PI-LAB KW - asthenosphere KW - oceanic lithosphere KW - shear velocity KW - surface wave tomography SN - 1525-2027 TI - Evolution of the oceanic lithosphere in the equatorial Atlantic From Rayleigh wave tomography, evidence for small?scale convection From the PI?LAB experiment AV - none ER - TY - JOUR N1 - https://doi.org/10.1029/2021JB022202 ID - soton450941 UR - https://eprints.soton.ac.uk/450941/ IS - 8 A1 - Harmon, Nicholas A1 - Wang, Shunguo A1 - Rychert, Catherine A. A1 - Constable, Steven A1 - Kendall, J Michael Y1 - 2021/08/11/ N2 -

The lithosphere-asthenosphere system is fundamental to our understanding of mantle convection and plate tectonics. The different sensitivities of seismic and electromagnetic methods can be used together to better constrain the properties of the system. Here, we re-examine the shear velocity model from Rayleigh waves in light of the magnetotelluric based resistivity models from the Passive Imaging of the Lithosphere Asthenosphere Boundary (PI-LAB) experiment near the equatorial Mid-Atlantic Ridge, with the goal of generating a structurally consistent velocity and resistivity model for the region. Cross-plots of the models suggest a linear or near-linear trend that is also in agreement with petrophysical predictions. We generate a new shear velocity model from the resistivity models based on petrophysical relationships. The new velocity model fits the phase velocity data, and the correlation coefficient between the shear velocity and resistivity models is increased. Much of the model can be predicted by expectations for a thermal half-space cooling model, although some regions require a combination of higher temperatures, volatiles, or partial melt. We use the petrophysical predictions to estimate the melt fraction, melt volatile content, and temperature structure of the asthenospheric anomalies. We find up to 4% melt, with the lowest resistivities and shear velocities explained by up to 20% water or 20% CO 2 in the melt or ?1% nearly pure sulfide melt, depending on the set of assumptions used. Melt is required in punctuated anomalies over broad depth ranges, and also in channels at the base of the lithosphere. Melt in the asthenosphere is dynamic, yet persistent on geologic timescales.

JF - Journal of Geophysical Research: Solid Earth VL - 126 KW - Lithosphere Asthenosphere KW - Magnetotellurics KW - Melt KW - Mid-Atlantic Ridge KW - Rayleigh Wave Tomography KW - small scale convection SN - 2169-9313 TI - Shear velocity inversion guided by resistivity structure from the PI-LAB Experiment for integrated estimates of partial melt in the mantle AV - none ER - TY - JOUR ID - soton470366 UR - https://eprints.soton.ac.uk/470366/ IS - 3-4 A1 - Harris, Elizabeth A1 - Marsh, Robert A1 - Grist, Jeremy P A1 - McCarthy, Gerard D. N2 - Hurricane activity has been higher since 1995 than in the 1970s and 1980s. This rise in activity has been linked to a warming Atlantic. In this study, we consider variability of the volume of water warmer than 26.5 ºC, considered widely to be the temperature threshold crucial to hurricane development. We find the depth of the 26.5 ºC isotherm better correlated with seasonal hurricane counts than SST in the early part of the Atlantic hurricane season in some regions. The volume of water transformed by surface heat fluxes to temperatures above 26.5 ºC is directly calculated using the Water Mass Transformation framework. This volume is compared with the year-to-year changes in the volume of water of this temperature to see how much of the volume can be explained using this calculation. In some years, there is notable correspondence between transformed and observed volume anomalies, but anomalies in other years must be largely associated with other processes, such as the divergence of horizontal heat transport associated with the AMOC. This technique provides evidence that, in a given year, coordinated physical mechanisms are responsible for the build-up of anomalous ocean heat; not only net surface heat exchange but also the convergence of horizontal heat transport from ocean currents, to provide fuel for larger numbers of intense hurricanes. VL - 59 TI - The water mass transformation framework and variability in hurricane activity AV - public EP - 972 N1 - Funding Information: This analysis was possible due to the public availability of the NCEP/NCAR Reanalysis Monthly Means and Other Derived Variables data (https://psl.noaa.gov/data/gridded/data.ncep.reanalysis.derived.surfaceflux.html), the NCEP Global Ocean Data Assimilation System (GODAS) data (https://psl.noaa.gov/data/gridded/data.godas.html) and International Best Track Archive for Climate Stewardship (IBTrACS) data (https://www.ncdc.noaa.gov/ibtracs/index.php?name=ib-v4-access). We thank two anonymous reviewers for perceptive comments, helping us to substantially improve the manuscript. Publisher Copyright: © 2022, The Author(s). Y1 - 2022/04/13/ JF - Climate Dynamics KW - Atlantic KW - Hurricane KW - Surface heat flux KW - Warm water anomalies KW - Water mass transformation SN - 0930-7575 SP - 961 ER - TY - JOUR ID - soton366900 UR - https://eprints.soton.ac.uk/366900/ IS - A A1 - Hartman, S.E. A1 - Hartman, M.C. A1 - Hydes, D.J. A1 - Smythe-Wright, D. A1 - Gohin, F. A1 - Lazure, P. Y1 - 2014/12// N2 - Unusually high chlorophyll values (~ 14 mg chl m-3 at 5 m depth), recorded on a ship of opportunity (SOO) in July 2010, indicated the occurrence of a potential Harmful Algal Bloom (HAB) in the Western approaches of the English Channel. This bloom, located at 49.7°N, 3.2°W was observed via complementary datasets. These included data from samples collected for microscopic phytoplankton identification, information from satellite maps to follow geographical bloom development and in situ data to identify hydrographic factors related to bloom initiation. The relationships between chlorophyll-fluorescence, temperature, salinity and wind speed were examined. The intense summer bloom predominantly consisted of the dinoflagellate Karenia mikimotoi and followed an increase in sea surface temperature (to 18.5 °C). A mid-channel bloom of this magnitude along the SOO route was last seen in 2003. In both years the peak biomass was associated with Karenia mikimotoi blooms, which occurred at the same location and coincided with the least saline, warmest water and lowest wind speeds. This study demonstrates that ships of opportunity are a useful tool to identify and track HAB events through continuous in situ measurements and for the frequent sampling opportunities that they provide. JF - Journal of Marine Systems VL - 140 KW - Karenia mikimotoi KW - Harmful Algae KW - wind speed KW - temperature KW - low salinity water KW - French Atlantic rivers KW - English Channel KW - Ferry-box SN - 0924-7963 TI - The role of hydrographic parameters, measured from a ship of opportunity, in bloom formation of Karenia mikimotoi in the English Channel SP - 39 AV - public EP - 49 ER - TY - JOUR ID - soton340661 UR - https://eprints.soton.ac.uk/340661/ IS - 5 A1 - Hartman, S.E. A1 - Lampitt, R.S. A1 - Larkin, K.E. A1 - Pagnani, M. A1 - Campbell, J. A1 - Gkritzalis, T. A1 - Jiang, Z-P. A1 - Pebody, C.A. A1 - Ruhl, H.A. A1 - Gooday, A.J. A1 - Bett, B.J. A1 - Billett, D.S.M. A1 - Provost, P. A1 - McLachlan, R. A1 - Turton, J.D. A1 - Lankester, S. Y1 - 2012/07// N2 - The Porcupine Abyssal Plain sustained observatory (PAP-SO) in the Northeast Atlantic (49°N 16.5°W; 4800 m) is the longest running open-ocean multidisciplinary observatory in the oceans around Europe. The site has produced high-resolution datasets integrating environmental and ecologically relevant variables from the surface to the seabed for >20 years. Since 2002, a full-depth mooring has been in place with autonomous sensors measuring temperature, salinity, chlorophyll-a fluorescence, nitrate, and pCO2. These complement ongoing mesopelagic and seabed observations on downward particle flux and benthic ecosystem structure and function. With national and European funding, the observatory infrastructure has been advanced steadily, with the latest development in 2010 involving collaboration between the UK's Meteorological Office and Natural Environment Research Council. This resulted in the first simultaneous atmospheric and ocean datasets at the site. All PAP-SO datasets are open access in near real time through websites and as quality-controlled datasets for a range of remote users using ftp sites and uploaded daily to MyOcean and the global telecommunications system for use in modelling activities. The combined datasets capture short-term variation (daily?seasonal), longer term trends (climate-driven), and episodic events (e.g. spring-bloom events), and the data contribute to the Europe-wide move towards good environmental status of our seas, driven by the EU's Marine Strategy Framework Directive (http://ec.europa.eu/environment/water/marine). JF - ICES Journal of Marine Science VL - 69 KW - Northeast Atlantic KW - observatory KW - Porcupine Abyssal Plain KW - time-series SN - 1054-3139 TI - The Porcupine Abyssal Plain fixed-point sustained observatory (PAP-SO): variations and trends from the Northeast Atlantic fixed-point time-series SP - 776 AV - none EP - 783 ER - TY - JOUR ID - soton362610 UR - https://eprints.soton.ac.uk/362610/ A1 - Hartman, Susan E. A1 - Hartman, Mark C. A1 - Hydes, David J. A1 - Jiang, Zong-Pei A1 - Smythe-Wright, Denise A1 - González-Pola, Cesar Y1 - 2014/08// N2 - A key challenge in oceanography is to capture and quantify processes that happen on short time scales, seasonal changes and inter-annual variations. To address this problem the P&O European Ferries Ltd. Ship MV Pride of Bilbao was fitted with a FerryBox from 2002 to 2010 and data returned to NOC in real time providing near continuous measurements between UK (Portsmouth) and Spain (Bilbao) of temperature, salinity, chlorophyll-fluorescence and oxygen. Additional monthly samples were collected on manned crossings. Over 6000 samples were analysed for nitrate (nitrate and nitrite) concentrations. The timing of nitrate concentration increases (with winter mixing) and decreases (with the spring bloom) are different on and off shelf and in autumn nitrate concentrations remain high on the shelf. Off shelf in the Bay of Biscay, the mixed layer depth assessed using Argo floats, was found to vary from 212 m in relatively mild winters (such as 2007/2008) to 476 m in cold winters (2009/2010). Years with deeper mixing were associated with an increase in nitrate concentrations in the surface waters (~3 µmol l-) and the increased vertical nutrient supply resulted in higher productivity the following spring. Bloom progression could be seen through the increase in oxygen anomaly and decrease in nitrate concentrations off shelf prior to changes further north on the shelf and phytoplankton growth was initiated as shoaling begins. The full dataset demonstrates that ships of opportunity, particularly ferries with consistently repeated routes, can deliver high quality in situ measurements over large time and space scales that currently cannot be delivered in any other way. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 106 KW - Nitrates KW - Time-series KW - Ship of opportunity KW - North East Atlantic KW - Bay of Biscay SN - 0967-0645 TI - Seasonal and inter-annual variability in nutrient supply in relation to mixing in the Bay of Biscay SP - 68 AV - public EP - 75 ER - TY - JOUR ID - soton375537 UR - https://eprints.soton.ac.uk/375537/ IS - 1 A1 - Hathorne, Ed C. A1 - Stichel, Torben A1 - Brück, Bastian A1 - Frank, Martin Y1 - 2015/12/20/ N2 -
The concentrations of rare earth elements (REEs) in seawater display systematic variations related to weathering inputs, particle scavenging and water mass histories. Here we investigate the REE concentrations of water column profiles in the Atlantic sector of the Southern Ocean, a key region of the global circulation and primary production. The data reveal a pronounced contrast between the vertical profiles in the Antarctic Circumpolar Current (ACC) and those south of the ACC in the Weddell Gyre (WG). The ACC profiles exhibit the typical increase of REE concentrations with water depth and a change in the shape of the profiles from near linear for the light REEs to more convex for the heavy REEs. In contrast, the WG profiles exhibit high REE concentrations throughout the water column with only the near surface samples showing slightly reduced concentrations indicative of particle scavenging. Seawater normalised REE patterns reveal the strong remineralisation signal in the ACC with the light REEs preferentially removed in surface waters and the mirror image pattern of their preferential release in deep waters. In the WG the patterns are relatively homogenous reflecting the prevalence of well-mixed Lower Circumpolar Deep Water (LCDW) that follows shoaling isopycnals in the region. In the WG particle scavenging of REEs is comparatively small and limited to the summer months by light limitation and winter sea ice cover. Considering the surface water depletion compared to LCDW and that the surface waters of the WG are replaced every few years, the removal rate is estimated to be on the order of 1 nmol m? 3 yr? 1 for La and Nd. The negative cerium anomalies observed in deep waters are some of the strongest found globally with only the deepest waters in parts of the Pacific having stronger anomalies. These deep waters have been isolated from fresh continental REE inputs during their long journey through the abyssal Indo-Pacific Ocean, which suggests that the high REE concentrations found in the ACC and WG reflect contributions from old deep waters.
JF - Marine Chemistry VL - 177 KW - Rare earth elements KW - Atlantic sector of the Southern Ocean KW - Weddell Gyre KW - GEOTRACES SN - 0304-4203 TI - Rare earth element distribution in the Atlantic sector of the Southern Ocean: The balance between particle scavenging and vertical supply SP - 157 AV - none EP - 171 ER - TY - JOUR ID - soton199269 UR - https://eprints.soton.ac.uk/199269/ IS - 16 A1 - Hawkins, E. A1 - Smith, R.S. A1 - Allison, L.C. A1 - Gregory, J.M. A1 - Woollings, T.J. A1 - Pohlmann, H. A1 - de Cuevas, B. Y1 - 2011/// JF - Geophysical Research Letters VL - 38 KW - AOGCM KW - Atlantic KW - bistability KW - freshwater transport KW - hysteresis KW - overturning circulation SN - 0094-8276 TI - Correction to ?Bistability of the Atlantic overturning circulation in a global climate model and links to ocean freshwater transport" AV - none ER - TY - JOUR ID - soton187801 UR - https://eprints.soton.ac.uk/187801/ A1 - Hawkins, S.J. A1 - Sugden, H.E. A1 - Mieszkowska, N. A1 - Moore, P.J. A1 - Poloczanska, E. A1 - Leaper, R. A1 - Herbert, R.J.H. A1 - Genner, M.J. A1 - Moschella, P.S. A1 - Thompson, R.C. A1 - Jenkins, S.R. A1 - Southward, A.J. A1 - Burrows, M.T. Y1 - 2009/// N2 - We review how intertidal biodiversity is responding to globally driven climate change, focusing on long-term data from rocky shores in the British Isles. Physical evidence of warming around the British Isles is presented and, whilst there has been considerable fluctuation, sea surface temperatures are at the highest levels recorded, surpassing previous warm periods (i.e. late 1950s). Examples are given of species that have been advancing or retreating polewards over the last 50 to 100 yr. On rocky shores, the extent of poleward movement is idiosyncratic and dependent upon life history characteristics, dispersal capabilities and habitat requirements. More southern, warm water species have been recorded advancing than northern, cold water species retreating. Models have been developed to predict likely assemblage composition based on future environmental scenarios. We present qualitative and quantitative forecasts to explore the functional consequences of changes in the identity, abundance and species richness of gastropod grazers and foundation species such as barnacles and canopy-forming algae. We forecast that the balance of primary producers and secondary consumers is likely to change along wave exposure gradients matching changes occurring with latitude, thereby shifting the balance between export and import of primary production. Increases in grazer and sessile invertebrate diversity are likely to be accompanied by decreasing primary production by large canopy-forming fucoids. The reasons for such changes are discussed in the context of emerging theory on the relationship between biodiversity and ecosystem functioning. JF - Marine Ecology Progress Series VL - 396 KW - Climate change KW - Intertidal KW - Range shifts KW - Biodiversity KW - Ecosystem functioning KW - Northeast Atlantic TI - Consequences of climate-driven biodiversity changes for ecosystem functioning of North European rocky shores SP - 245 AV - restricted EP - 259 ER - TY - JOUR ID - soton349159 UR - https://eprints.soton.ac.uk/349159/ IS - C3 A1 - Hazeleger, Wilco A1 - Drijfhout, Sybren Y1 - 2006/03// N2 - Pathways of subtropical cells (STCs) and the basin-wide meridional overturning circulation (MOC) are studied in the tropical Atlantic using a particle tracking algorithm and transports from a high-resolution ocean model. Here 16 Sv (=106 m3 s-1) of MOC water flows to the equator from the south, primarily in the North Brazil Current. The MOC water recirculates in the tropics and, after crossing the equator about half of it, stays along the western boundary and the other half loops in a cyclonic circulation northward to join the North Equatorial Current. The STC on the Southern Hemisphere has a strength of 4 Sv. The northern STC has a strength of 1.5 Sv; it is confined to the retroflection area close to the equator and it contains primarily MOC water. In total, 5.5 Sv of MOC water entrains into the mixed layer in the tropical Atlantic. Here 2 Sv of MOC water recirculates in the southern STC and 1.5 Sv in the northern STC. The STCs are weaker than suggested from observations, but the interior flows in the model compare well to observations. The heat transport divergence that is associated with warming of MOC water masses between 10°S and 10°N is 0.22 PW (=1015W). The fresh water transport divergence of MOC water masses in the tropical Atlantic is 0.16 Sv. It is concluded that the MOC can substantially affect the tropical circulation, but the tropical circulation itself can also affect MOC properties. JF - Journal of Geophysical Research VL - 111 KW - moc KW - stc KW - tropical atlantic SN - 0148-0227 TI - Subtropical cells and meridional overturning circulation pathways in the tropical Atlantic SP - C03013 AV - none EP - [13pp] ER - TY - JOUR ID - soton50062 UR - http://www.sciencedirect.com/science/journal/00796611 IS - 1 A1 - Heath, M.R. A1 - Rasmussen, J. A1 - Ahmed, Y. A1 - Allen, J. A1 - Anderson, C.I.H. A1 - Brierley, A.S. A1 - Brown, L. A1 - Bunker, A. A1 - Cook, K. A1 - Davidson, R. A1 - Fielding, S. A1 - Gurney, W.S.C. A1 - Harris, R. A1 - Hay, S. A1 - Henson, S. A1 - Hirst, A.G. A1 - Holliday, N.P. A1 - Ingvarsdottir, A. A1 - Irigoien, X. A1 - Lindeque, P. A1 - Mayor, D.J. A1 - Montagnes, D. A1 - Moffat, C. A1 - Pollard, R. A1 - Richards, S. A1 - Saunders, R.A. A1 - Sidey, J. A1 - Smerdon, G. A1 - Speirs, D. A1 - Walsham, J. A1 - Waniek, J. A1 - Webster, L. A1 - Wilson, D. Y1 - 2008/01// N2 - Continuous Plankton Recorder data suggest that the Irminger Sea supports a major proportion of the surface-living population of the copepod Calanus finmarchicus in the northern North Atlantic, but there have been few studies of its population dynamics in the region. In this paper, we document the seasonal changes in the demographic structure of C. finmarchicus in the Irminger Sea from a field programme during 2001/2002, and the associations between its developmental stages and various apparent bio-physical zones. Overwintering stages were found widely at depth (>500 m) across the Irminger Sea, and surviving females were widely distributed in the surface waters the following spring. However, recruitment of the subsequent generation was concentrated around the fringes of the Irminger Sea basin, along the edges of the Irminger and East Greenland Currents, and not in the central basin. In late summer animals were found descending back to overwintering depths in the Central Irminger Sea. The key factors dictating this pattern of recruitment appear to be (a) the general circulation regime, (b) predation on eggs in the spring, possibly by the surviving G0 stock, and (c) mortality of first feeding naupliar stages in the central basin where food concentrations appear to be low throughout the year.
We compared the demographic patterns in 2001/2002 with observations from the only previous major survey in 1963 and with data from the Continuous Plankton Recorder (CPR) surveys. In both previous data sets, the basic structure of G0 ascent from the central basin and G1 recruitment around the fringes was a robust feature, suggesting that it is a recurrent phenomenon. The Irminger Sea is a complex mixing zone between polar and Atlantic water masses, and it has also been identified as a site of sporadic deep convection. The physical oceanographic characteristics of the region are therefore potentially sensitive to climate fluctuations. Despite this, the abundance of C. finmarchicus in the region, as measured by the CPR surveys, appears not to have responded to climate factors linked to the North Atlantic Oscillation Index, in contrast with the stocks in eastern Atlantic areas. We speculate that this may because biological factors (production and mortality), rather than transport processes are the key factors affecting the population dynamics in the Irminger Sea. JF - Progress in Oceanography VL - 76 KW - Plankton KW - Oceanography KW - Atlantic Ocean KW - Greenland KW - Copepods KW - Mortality SN - 0079-6611 TI - Spatial demography of Calanus finmarchicus in the Irminger Sea SP - 39 AV - none EP - 88 ER - TY - JOUR ID - soton368389 UR - https://eprints.soton.ac.uk/368389/ A1 - Hernández-Sánchez, Maria T. A1 - LaRowe, Douglas E. A1 - Deng, Feifei A1 - Homoky, William B. A1 - Browning, Thomas J. A1 - Martin, Patrick A1 - Mills, Rachel A. A1 - Pancost, Richard D. Y1 - 2014/11// N2 - Sedimentary biomarker distributions can record ocean productivity and community structure, but their interpretation must consider alteration during organic matter (OM) export and burial. Large changes in the water column redox state are known to impact on the preservation of biomarkers, but more subtle variation in sediment redox conditions, characteristic of major modern ocean basins, have been less thoroughly investigated. Here we evaluate changes in biomarker distributions during sinking and burial across a nearshore to offshore transect in the southwestern Cape Basin (South East Atlantic), which includes a range of sedimentary environments. Biomarker concentrations and distributions in suspended particulate matter from the upper water column were determined and compared with underlying sedimentary biomarker accumulation rates and distributions. Biomarker distributions were similar in surface and subsurface waters, indicating that the OM signature is exported from the ocean mixed layer with minimal alteration. We show that, while export production (100 m) is similar along this transect, 230Thxs-corrected biomarker accumulation rate varies by over an order of magnitude in sediments and is directly associated with sedimentary redox conditions, ranging from oxic to nitrogenous-ferruginous. Biomarker distributions are dominated by sterols in surface water, and by alkenones in underlying sediments, which we propose to be primarily the result of selective preservation. Notably, the difference in sediment O2 penetration depth is associated with relative biomarker preservation. Subtle variation in sedimentary redox conditions has a dramatic impact on the distribution of preserved biomarkers. We discuss mechanisms for preferential degradation of specific biomarkers within this setting. JF - Organic Geochemistry VL - 76 KW - Biomarker preservation KW - Atlantic Ocean KW - Paleoproductivity proxies SN - 0146-6380 TI - Further insights into how sediment redox status controls the preservation and composition of sedimentary biomarkers SP - 220 AV - none EP - 234 ER - TY - JOUR ID - soton386234 UR - https://eprints.soton.ac.uk/386234/ A1 - Herrmann, Rachel B. Y1 - 2016/03// N2 - In 1800 black Loyalists in Sierra Leone participated in an event that historians have called a rebellion. Reinterpreting the 1800 rebellion as a food riot reveals more extensive black Loyalist political activity in the 1790s, greater cooperation between black Loyalists and white councilmen, and increased animosity between black Loyalists and Africans. Black Loyalists created food legislation with the approval of the Sierra Leone Council, but those laws fostered disagreements with Africans. When the Sierra Leone Council revoked the black Loyalists? law-making abilities, colonists rioted to reclaim the political and legal rights that they developed through their food legislation. JF - Slavery & Abolition KW - black loyalists KW - food history KW - atlantic world KW - sierra leone KW - riot KW - american revolution SN - 0144-039X TI - Rebellion or riot?: black Loyalist food laws in Sierra Leone SP - 1 AV - public EP - 31 ER - TY - JOUR ID - soton378189 UR - https://eprints.soton.ac.uk/378189/ IS - 6 A1 - Hetzinger, S. A1 - Halfar, J. A1 - Mecking, J.V. A1 - Keenlyside, N.S. A1 - Kronz, A. A1 - Steneck, R.S. A1 - Adey, W.H. A1 - Lebednik, P.A. Y1 - 2012/09// N2 - Decadal- to multidecadal variability in the extra-tropical North Pacific is evident in 20th century instrumental records and has significant impacts on Northern Hemisphere climate and marine ecosystems. Several studies have discussed a potential linkage between North Pacific and Atlantic climate on various time scales. On decadal time scales no relationship could be confirmed, potentially due to sparse instrumental observations before 1950. Proxy data are limited and no multi-centennial high-resolution marine geochemical proxy records are available from the subarctic North Pacific. Here we present an annually-resolved record (1818?1967) of Mg/Ca variations from a North Pacific/Bering Sea coralline alga that extends our knowledge in this region beyond available data. It shows for the first time a statistically significant link between decadal fluctuations in sea-level pressure in the North Pacific and North Atlantic. The record is a lagged proxy for decadal-scale variations of the Aleutian Low. It is significantly related to regional sea surface temperature and the North Atlantic Oscillation (NAO) index in late boreal winter on these time scales. Our data show that on decadal time scales a weaker Aleutian Low precedes a negative NAO by several years. This atmospheric link can explain the coherence of decadal North Pacific and Atlantic Multidecadal Variability, as suggested by earlier studies using climate models and limited instrumental data. JF - Climate Dynamics VL - 39 KW - Aleutian Low KW - North Atlantic Oscillation KW - North Pacific KW - Atlantic Multidecadal Variability KW - Mg/Ca KW - Coralline algae SN - 0930-7575 TI - Marine proxy evidence linking decadal North Pacific and Atlantic climate SP - 1447 AV - none EP - 1455 ER - TY - JOUR ID - soton41931 UR - https://eprints.soton.ac.uk/41931/ IS - 14-16 A1 - Heywood, J.L. A1 - Zubkov, M.V. A1 - Tarran, G.A. A1 - Fuchs, B.M. A1 - Holligan, P.M. Y1 - 2006/// N2 - Temporal changes of prokaryoplankton in three different provinces of the Atlantic Ocean were examined between 1996 and 2004. The abundance and integrated biomass of three prokaryote groups (Prochlorococcus spp., Synechococcus spp. and other prokaryoplankton) were used to detect standing stock changes in the northern and southern oligotrophic gyres and in the equatorial region. Mean cell concentrations (±standard error of the mean) of Prochlorococcus spp., Synechococcus spp. and other prokaryoplankton above the nitracline in the northern oligotrophic gyre were 1.2×105 (±0.08), 5.0×103 (±1.22) and 0.9×106 (±0.03) cells mL-1, respectively. Similar concentrations of 1.2×105 (±0.06) Prochlorococcus mL-1, 1.9×103 (±0.29) Synechococcus mL?1 and 0.7×106 (±0.03) other prokaryoplankton mL-1 were measured in the southern oligotrophic gyre, with higher concentrations of all prokaryote groups in equatorial waters. Integrated biomass (±standard error of the mean) of Prochlorococcus spp. above the nitracline was 173 (±21) mg C m-2 in the northern oligotrophic gyre, 190 (±14) mg C m-2 in the southern oligotrophic gyre and 141 (±15) mg C m-2 in the equatorial region. Synechococcus spp. biomass was lower in each of the three provinces (18 (±2), 17 (±4) and 32 (±5) mg C m-2, respectively). The data showed no statistically significant inter-annual variability in Prochlorococcus or Synechococcus abundance or integrated biomass above the nitracline in any of the provinces. The abundance and biomass of the remaining prokaryoplankton were variable, but these variations could not be ascribed to seasonal differences and did not follow a clear inter-annual trend. In light of results presented here, recommendations on the frequency and spatial resolution of sampling needed to characterise province-scale temporal variability of prokaryoplankton communities have been suggested.
JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 53 KW - Atlantic Ocean KW - Atlantic Meridional Transect KW - Picoplankton community composition KW - Oligotrophic gyre KW - Prochlorococcus KW - Synechococcus SN - 0967-0645 TI - Prokaryoplankton standing stocks in oligotrophic gyre and equatorial provinces of the Atlantic Ocean: evaluation of inter-annual variability SP - 1530 AV - none EP - 1547 ER - TY - GEN N1 - Funding Information: We acknowledge constructive comments by Martha Buckley and one anonymous reviewer as well as from Harry Bryden and David Webb. We thank Alain Colin de Verdi?re for providing the barotropic stream function data. J. H. and A. B. acknowledge funding from the NERC, the NERC RAPID-AMOC project DYNAMOC (NE/M005097/1), and the NERC project ACSIS (NE/N018044/1). This work used the ARCHER U.K. National Supercomputing Service (http://www.archer.ac.uk) and is a contribution to the DRAKKAR project (https://www.drakkarocean.eu). J. S. is partially supported by the International Laboratory for High Resolution Earth System Prediction (iHESP)?a collaboration among the Qingdao National Laboratory for Marine Science and Technology Development Center (QNLM), Texas A&M University (TAMU), and the National Center for Atmospheric Research (NCAR). D. Sein acknowledges the state assignment of FASO Russia (Theme 0149-2019-0015). M. R., D. I., and D. Sein acknowledge PRIMAVERA funding received from the European Commission under Grant Agreement 641727 of the Horizon 2020 research programme, and M. R. and H. H. were supported by the Joint UK BEIS/Defra Met Office Hadley Centre Climate Programme (GA01101). A. K.was funded by the Australian Research Council Linkage Program (LP160100073). L. Thompson acknowledges support from NASA (Grant NNX17AH56G). W. W. was supported by the HiLAT-RASM project of the U.S. Department of Energy's Regional and Global Model Analysis (RGMA) program. The ACCESS-OM2 suite was configured by COSIMA (cosima.org.au) which is funded by the Australian Research Council (Linkage Program LP160100073). It was also supported by the ARC Centre of Excellence for Climate Extremes (Australian Research Council Grant CE170100023) and undertaken using the National Computational Infrastructure (NCI), which is supported by the Australian Government. Publisher Copyright: ©2020. The Authors. ID - soton437800 UR - https://eprints.soton.ac.uk/437800/ A1 - Hirschi, Joël J.?m. A1 - Barnier, Bernard A1 - Böning, Claus A1 - Biastoch, Arne A1 - Blaker, Adam T. A1 - Coward, Andrew A1 - Danilov, Sergey A1 - Drijfhout, Sybren A1 - Getzlaff, Klaus A1 - Griffies, Stephen M. A1 - Hasumi, Hiroyasu A1 - Hewitt, Helene A1 - Iovino, Doroteaciro A1 - Kawasaki, Takao A1 - Kiss, Andrew E. A1 - Koldunov, Nikolay A1 - Marzocchi, Alice A1 - Mecking, Jennifer V. A1 - Moat, Ben A1 - Molines, Jean?marc A1 - Myers, Paul G. A1 - Penduff, Thierry A1 - Roberts, Malcolm A1 - Treguier, Anne?marie A1 - Sein, Dmitry V. A1 - Sidorenko, Dmitry A1 - Small, Justin A1 - Spence, Paul A1 - Thompson, Luanne A1 - Weijer, Wilbert A1 - Xu, Xiaobiao Y1 - 2020/04/01/ N2 - The Atlantic meridional overturning circulation (AMOC) represents the zonally integrated stream function of meridional volume transport in the Atlantic Basin. The AMOC plays an important role in transporting heat meridionally in the climate system. Observations suggest a heat transport by the AMOC of 1.3 PW at 26°N ? a latitude which is close to where the Atlantic northward heat transport is thought to reach its maximum. This shapes the climate of the North Atlantic region as we know it today. In recent years there has been significant progress both in our ability to observe the AMOC in nature and to simulate it in numerical models. Most previous modeling investigations of the AMOC and its impact on climate have relied on models with horizontal resolution that does not resolve ocean mesoscale eddies and the dynamics of the Gulf Stream/North Atlantic Current system. As a result of recent increases in computing power, models are now being run that are able to represent mesoscale ocean dynamics and the circulation features that rely on them. The aim of this review is to describe new insights into the AMOC provided by high?resolution models. Furthermore, we will describe how high?resolution model simulations can help resolve outstanding challenges in our understanding of the AMOC. KW - Atlantic Meridional Overturning KW - high-resolution modeling KW - mesoscale SN - 2169-9275 TI - The Atlantic meridional overturning circulation in high resolution models AV - public EP - 81 ER - TY - JOUR ID - soton351184 UR - https://eprints.soton.ac.uk/351184/ IS - 1-2 A1 - Hodell, David A. A1 - Minth, Emily Kay A1 - Curtis, Jason H. A1 - McCave, I. Nicholas A1 - Hall, Ian R. A1 - Channell, James E.T. A1 - Xuan, Chuang Y1 - 2009/10/30/ N2 - Changes in surface and deep-water hydrography were inferred from variations in stable isotopes and sortable silt mean grain size, respectively, on the southern Gardar Drift in the subpolar North Atlantic. The bathymetric ?13C gradient during the penultimate glaciation was similar to the last glaciation with high- ?13C Glacial North Atlantic Intermediate water above ? 2000 m, and low- ?13C water derived from the Southern Ocean below. During Termination II, low-?13C water was present throughout the water column with minimum values at intermediate depths (? 1500?2000 m) and below 3000 m. This pattern continued well into the early part of the Last Interglacial (LIG) period. Sortable silt mean size at 3275 m suggests that deep-water circulation on Gardar Drift was relatively weak during the earliest part of the LIG (128 to 124.5 ka) when planktonic ?18O was at a minimum, reflecting warming and/or reduced salinity. We suggest that low- ?13C water and slow current speed on Gardar Drift during the early part of the LIG was related to increased melt water fluxes to the Nordic Seas during peak boreal summer insolation, which decreased the flux and/or density of overflow to the North Atlantic. The resumption of the typical interglacial pattern of strong, well-ventilated Iceland Scotland Overflow Water was delayed until ? 124 ka. These changes may have affected Atlantic Meridional Overturning Circulation. JF - Earth and Planetary Science Letters VL - 288 KW - last interglacial KW - north atlantic KW - gardar drift KW - iceland?scotland overflow KW - thermohaline circulation KW - surface hydrography SN - 0012-821X TI - Surface and deep-water hydrography on Gardar Drift (Iceland Basin) during the last interglacial period SP - 10 AV - none EP - 19 ER - TY - RPRT N1 - Deposited at the request of D.A. Purdie. Major revision of SOC Research & Consultancy Report No. 82 (2004). Report now made completely open access 07/01/2013. ID - soton49735 UR - https://eprints.soton.ac.uk/49735/ A1 - Holley, S.E. A1 - Purdie, D.A. A1 - Hydes, D.J. A1 - Hartman, M.C. Y1 - 2007/10/02/ N2 - The Environment Agency (EA) has to make a eutrophication status assessment of the Solent and its harbours every four years. This requires a review of the frequency and magnitude of phytoplankton blooms. To assist with this process SOC has prepared this report to provide a "meta-data base" describing the relevant data sets collected by SOC between 1999 and 2003. It provides details of :-
(1) methods used to collect the data
(2) errors associated with the methods
(3) calibration and quality control procedures used
(4) changes in procedures (5) references to technical reports and theses containing detailed descriptions of the methods used.
Changes in concentrations of chlorophyll in relation to concentrations of nutrients at SOC study sites in Southampton Water are plotted in graphs. The occurrence of bloom events and processes of bloom limitation are described. In particular observations of the variation of chlorophyll concentrations made using the FerryBox route between Town Quay Southampton and Cowes Isle of Wight are described and the development of the systems and associated problems are detailed. The information is presented as (i) graphs of the whole data set at all locations against time for each year (ii) 3D maps of the variation in concentrations with location and time (iii) time series for single locations along the FerryBox track. PB - National Oceanography Centre T3 - 31 KW - eutrophication KW - FerryBox KW - monitoring KW - nutrients KW - plankton blooms KW - Solent KW - Southampton Water KW - time seriesmacrobethos KW - Megacorer KW - pockmarks KW - salt diapirs KW - SE Atlantic KW - seabed KW - sediment particle size KW - sediments KW - species diversity KW - total nitrogen KW - Total Organic Carbon M1 - project_report TI - 5 years of plankton monitoring in Southampton Water and the Solent including FerryBox, Dock Monitor and discrete sample data AV - public EP - 66 ER - TY - JOUR ID - soton1982 UR - http://www.agu.org/pubs/crossref/2003/2002JC001344.shtml IS - C8 A1 - Holliday, N.P. Y1 - 2003/// N2 - The upper ocean of the Rockall Trough exhibits coherent interannual variations in temperature and salinity over the past 26 years, with highs in the mid-1980s and late 1990s and lows in the late 1970s and early 1990s, and with ranges of ±0.5°C and ±0.05 in salinity. The origins of the interannual changes are discussed, covering three potential influencing factors: the propagation of anomalies developed upstream of the basin, the effect of local air-sea interaction, and the result of changes of regional circulation bringing different water masses into the region. The changes in heat and freshwater content of the upper ocean are directly compared to observed variations in air-sea heat and freshwater fluxes over the period of the time series. It is shown that the role of the atmosphere in locally altering the oceanic properties, particularly salinity, is relatively small and insufficient to explain the changes. Two recent hydrographic surveys are analyzed to ascertain how the distribution of water masses to the south of the basin may influence the properties of the northern Rockall Trough upper ocean, and the results are reviewed in the context of historical analyses. It is found that the critical factor in determining the properties is the varying amount of relatively cool and fresh North Atlantic Current water mixing with the dominant water mass, the warm saline Eastern North Atlantic Central Water at the entrance to the basin. Variations of inflowing water masses are caused by east-west changes in the location of the subpolar front, and the relationship of these changes in regional circulation to the North Atlantic wind stress field is discussed. JF - Journal of Geophysical Research VL - 108 KW - AIR SEA INTERACTION KW - NORTHEAST ATLANTIC OCEAN KW - ATLNE KW - ROCKALL TROUGH KW - ATLNENROC KW - INTERANNUAL VARIABILITY KW - WATER MIXING KW - OCEANCIRCULATION KW - GEOLOGY SN - 0148-0227 TI - Air-sea interaction and circulation changes in the northeast Atlantic AV - none ER - TY - JOUR ID - soton2045 UR - https://eprints.soton.ac.uk/2045/ A1 - Holliday, N.P. Y1 - 2003/// JF - ICES Marine Science Symposia VL - 219 KW - ATLNENROC KW - ROCKALL TROUGH KW - NORTH ATLANTIC KW - ATLN KW - TEMPERATURE KW - AIR-WATER EXCHANGES KW - SALINITY KW - OCEAN CIRCULATION KW - INTERANNUAL VARIABILITY TI - Extremes in temperature and salinity during the 1990s in the northern Rockall Trough: results from the 'Ellett line' SP - 95 AV - none EP - 101 ER - TY - JOUR ID - soton65724 UR - http://ams.allenpress.com/perlserv/?request=get-document&doi=10.1175%2F2009JPO4160.1 IS - 8 A1 - Holliday, N.P. A1 - Bacon, S. A1 - Allen, J.T. A1 - McDonagh, E.L. Y1 - 2009/08// N2 - The circulation and volume transports in the western boundary currents around Cape Farewell, Greenland, are derived from full-depth hydrographic and velocity measurements from August-September, 2005. The western boundary currents from surface to seafloor transport 40.5 ± 8.1 Sv southwards in the Irminger Sea, and 53.8 ± 10.8 Sv northwards in the Labrador Sea. The Deep Western Boundary Current (DWBC, defined as water with potential density greater than 27.80 kg m-3) transports 12.3 ± 2.5 Sv southwards in the Irminger Sea. The deep water transport is reduced south of Cape Farewell, where it changes flow direction from southwards to northwards (the south corner). At a section over the Eirik Ridge, a bathymetric feature extending southwest of Cape Farewell, the DWBC transports 8.7 ± 1.7 Sv westwards. The reduction in transport at the south corner is associated with decreased velocities within the deepest layers, and the volumetric loss of the most saline deep water types. The observations suggest that the part of the shallow and deep western boundary currents diverge at the south corner. Downstream in the eastern Labrador Sea the deep water transport is increased to 19.7 ± 3.9 Sv northwards, with the addition of recirculating denser deep waters. The representativeness of the results from the semi-synoptic survey are discussed with reference to companion current meter measurements of the DWBC. JF - Journal of Physical Oceanography VL - 39 KW - western boundary current transport north atlantic SN - 0022-3670 TI - Circulation and transport in the western boundary currents at Cape Farewell, Greenland SP - 1854 AV - public EP - 1870 ER - TY - RPRT ID - soton294 UR - https://eprints.soton.ac.uk/294/ A1 - Holliday, N.P. A1 - Griffiths, C.R. Y1 - 2000/// N2 - The report describes the RRS Discovery Cruise 245, designed as a repeat of the hydrographic section that includes the Ellett line from Scotland to Rockall, and the SOC extension to Iceland.

The section consisted of stations for CTD, LADCP, chemistry (nutrients, oxygen) and biology (chlorophyll). Continuous measurements of high precision position and heading navigation data were made, also of surface currents (VM-ADCP), depth, surface temperature and salinity, surface nutrients and high-quality meteorological measurements. The cruise objectives also included recovering two deep ocean and two shelf current meter moorings, and collecting shallow sediment cores in the Muck Deep, a shelf depression. The cruise was severely hit by bad weather and as a consequence not all the scientific objectives were achieved. PB - Southampton Oceanography Centre, University of Southampton T3 - 29 KW - ADCP KW - ATLN KW - cruise 245 2000 KW - CTD observations KW - current meters KW - Discovery KW - Iceland Basin KW - Irish Sea KW - LADCP KW - Multicore KW - Muck Deep KW - North Atlantic KW - nutrients KW - oxygen KW - repeat hydrography KW - Rockall Trough KW - shelf-edge current KW - VM-ADCP KW - water exchange KW - winter convection M1 - project_report TI - RRS Discovery Cruise 245, 27 Jan-20 Feb 2000. A hydrographic section from Scotland to Iceland AV - public EP - 80 ER - TY - RPRT ID - soton164021 UR - https://eprints.soton.ac.uk/164021/ Y1 - 2010/// PB - International Council for the Exploration of the Sea T3 - 304 Special Issue KW - ocean climate KW - north atlantic KW - time series observations SN - 1017-6195 ED - Holliday, N.P. ED - Hughes, S.L. ED - Beszczynska-Moller, A. M1 - project_report TI - ICES Report on Ocean Climate 2009 AV - none EP - 67 ER - TY - RPRT N1 - Deposited by Jane Conquer ID - soton68724 UR - https://eprints.soton.ac.uk/68724/ Y1 - 2009/09// PB - International Council for the Exploration of the Sea T3 - 298 Special Issue KW - ocean climate KW - north atlantic KW - time series observations SN - 1017-6195 ED - Holliday, N.P. ED - Hughes, S.L. ED - Beszczynska-Moller, A. M1 - project_report TI - ICES Report on Ocean Climate 2008 AV - none EP - 66 ER - TY - JOUR ID - soton384385 UR - https://eprints.soton.ac.uk/384385/ IS - 5 A1 - Holmes, N. A1 - Langdon, P.G. A1 - Caseldine, C.J. A1 - Wastegård, S. A1 - Leng, M.J. A1 - Croudace, I.W. A1 - Davies, S.M. Y1 - 2016/05// N2 - The aim of this research was to create a decadal scale terrestrial quantitative palaeoclimate record for NW Iceland from lake sediments for the last millennium. Geochemical, stable isotope and chironomid reconstructions were obtained from a lake sequence constrained by tephra deposits on the Snæfellsnes peninsula, W Iceland. Obtaining a quantitative record proved problematic, but the qualitative chironomid record showed clear trends associated with past summer temperatures, and the sedimentological records provided evidence for past changes in precipitation, mediated through catchment soil inwash. When the full range of chronological uncertainty is considered, four clear phases of climatic conditions were identified: (1) a relatively warm phase between AD 1020 ? 1310; (2) a relatively stable period between AD 1310 and AD 1510, cooler than the preceding period, but still notably warmer that the second half of the millennium; (3) a consistent reduction of temperatures between AD 1560 ? 1810, with the coolest period between AD 1680-1810; (4) AD 1840-2000 has temperatures mainly warmer than in the preceding two centuries, with a rising trend and increased variability from c. AD 1900 onwards. The reconstructions show clearly that the first half of the millennium experienced warmer climatic conditions than the second half, with a return to the warmer climate only occurring in the last c. 100 years. Much of the variability of the chironomid record can be linked to changes in the North Atlantic Oscillation (NAO). The reconstructions presented can track low frequency and long-term trends effectively and consistently but high resolution and calibrated quantitative records remain more of a challenge ? not just in finding optimal sedimentary deposits, but also in finding the most reliable proxy. It is this that presents the real challenge for Holocene climate reconstruction from this key area of the North Atlantic. JF - The Holocene VL - 26 KW - iceland KW - palaeolimnology KW - chironomids KW - little ice age KW - medieval climate anomaly KW - north atlantic oscillation SN - 0959-6836 TI - Climatic variability during the last millennium in Western Iceland from lake sediment records SP - 756 AV - public EP - 771 ER - TY - JOUR ID - soton364835 UR - https://eprints.soton.ac.uk/364835/ IS - B A1 - Holt, Jason A1 - Icarus Allen, J. A1 - Anderson, Thomas R. A1 - Brewin, Robert A1 - Butenschon, Momme A1 - Harle, James A1 - Huse, Geir A1 - Lehodey, Patrick A1 - Lindemann, Christian A1 - Memery, Laurent A1 - Salihoglu, Baris A1 - Senina, Inna A1 - Yool, Andrew Y1 - 2014/12// N2 - It has long been recognized that there are strong interactions and feedbacks between climate, upper ocean biogeochemistry and marine food webs, and also that food web structure and phytoplankton community distribution are important determinants of variability in carbon production and export from the euphotic zone. Numerical models provide a vital tool to explore these interactions, given their capability to investigate multiple connected components of the system and the sensitivity to multiple drivers, including potential future conditions. A major driver for ecosystem model development is the demand for quantitative tools to support ecosystem-based management initiatives. The purpose of this paper is to review approaches to the modelling of marine ecosystems with a focus on the North Atlantic Ocean and its adjacent shelf seas, and to highlight the challenges they face and suggest ways forward. We consider the state of the art in simulating oceans and shelf sea physics, planktonic and higher trophic level ecosystems, and look towards building an integrative approach with these existing tools. We note how the different approaches have evolved historically and that many of the previous obstacles to harmonisation may no longer be present. We illustrate this with examples from the on-going and planned modelling effort in the Integrative Modelling work package of the EURO-BASIN programme. JF - Progress in Oceanography VL - 129 KW - EURO BASIN KW - North Atlantic KW - Ecosystem Modelling KW - NEMO KW - PISCES KW - MEDUSA KW - ERSEM SN - 0079-6611 TI - Challenges in integrative approaches to modelling the marine ecosystems of the North Atlantic: Physics to Fish and Coasts to Ocean SP - 285 AV - public EP - 313 ER - TY - JOUR ID - soton375717 UR - https://eprints.soton.ac.uk/375717/ IS - 1-3 A1 - Hopwood, M.J. A1 - Bacon, S. A1 - Arendt, K. A1 - Connelly, D.P. A1 - Statham, P.J. Y1 - 2015/05// N2 -
Recent work has shown that glaciers are a globally significant source of the micronutrient Fe to the ocean. Polar regions are particularly susceptible to climate change and have been subject to pronounced warming in the past few decades. In response to this warming, the volume of glacial meltwater runoff from Greenland has increased. This meltwater has a relatively high particulate and dissolved Fe content. Seasonal Fe limitation of marine ecosystems has been found in parts of the North Atlantic, so it has been proposed that increasing fluxes of Fe rich meltwater from Greenland to the North Atlantic could alleviate this Fe limitation and thereby increase marine primary production. However, here we use a synthesis of biogeochemical and physical oceanography studies to suggest that the physical circulation around Greenland does not favour direct export of dissolved or particulate Fe from inshore to offshore waters. The Fe budget in surface waters of the North Atlantic may therefore be insensitive to increasing meltwater fluxes from Greenland.
JF - Biogeochemistry VL - 124 KW - Iron KW - North Atlantic KW - Glacial flour KW - Greenland SN - 0168-2563 TI - Glacial meltwater from Greenland is not likely to be an important source of Fe to the North Atlantic SP - 1 AV - none EP - 11 ER - TY - JOUR ID - soton439724 UR - https://eprints.soton.ac.uk/439724/ A1 - Horton, Tammy A1 - Cooper, Harry A1 - Vlierboom, Rianna A1 - Thurston, Michael A1 - Hauton, Chris A1 - Young, C. Robert Y1 - 2020/04/01/ N2 - The genus Eurythenes S. I. Smith in Scudder, 1882, has been the focus of integrated molecular and morphological taxonomy studies in recent years, resulting in the number of species in the genus increasing from three to eight. Samples of Eurythenes spp. collected using free-fall baited traps from the Porcupine Abyssal Plain (PAP), North East Atlantic Ocean, at 4850 m were examined in this study to investigate the identity of the species found using molecular barcoding methods. Mitochondrial COI analysis confirms the presence of E. maldoror at PAP and data from the nuclear 28S rDNA gene provides independent confirmation of this observation. A new, undescribed species that is clearly divergent from all other known species and molecular lineages was identified, which can be distinguished morphologically from known species. A specimen within the E. magellanicus lineage was also found at the site. We discuss the presence of these three Eurythenes species at the Porcupine Abyssal Plain. JF - Progress in Oceanography VL - 183 KW - Abyssal plains KW - Amphipoda KW - Eurythenes KW - North Atlantic KW - Porcupine Abyssal Plain KW - Scavengers SN - 0079-6611 TI - Molecular phylogenetics of deep-sea amphipods (Eurythenes) reveal a new undescribed species at the Porcupine Abyssal Plain, North East Atlantic Ocean AV - public ER - TY - JOUR ID - soton352178 UR - https://eprints.soton.ac.uk/352178/ IS - 5-6 A1 - Horton, Tammy A1 - Thurston, Michael Y1 - 2013/// N2 - A new species of the deep-sea scavenging genus Hirondellea (Crustacea: Amphipoda) is described from bathyal depths in the Azores region and on the Mid-Atlantic Ridge. The new species belongs to a group of Hirondellea species which possess an incised inner ramus of uropod 2 and an anteriorly directed spine on epimeron 1. It can be distinguished from other members of this group by a combination of characters: the gnathopod 1 and 2 palm shape; the broadly rounded epimeron 3; the longer telson and broadly rounded head lobe; and the broadly rounded epistome. The species most closely resembles H. wolfendeni, from which it can be distinguished by the shape of the propod of gnathopod 2 and the length of the pereopod 7 propodus. An updated key to the genus Hirondellea is provided. JF - Marine Biology Research VL - 9 KW - Crustacea KW - Amphipoda KW - Lysianassoidea KW - Hirondelleidae KW - North Atlantic Ocean KW - Mid-Atlantic Ridge KW - Hirondellea SN - 1745-1000 TI - Hirondellea namarensis (Crustacea: Amphipoda: Lysianassoidea: Hirondelleidae), a new deep-water scavenger species from the Mid-Atlantic Ridge SP - 554 AV - none EP - 562 ER - TY - JOUR ID - soton377435 UR - https://eprints.soton.ac.uk/377435/ IS - 1 A1 - Horton, Tammy A1 - Thurston, Michael H. Y1 - 2015/08// N2 - The genus Paracallisoma (Crustacea: Amphipoda) is revised and the type species, Paracallisoma alberti is redescribed based on holotype material supplemented with new material from the region of the type locality. This revision results in the establishment of two new genera, Pseudocallisoma gen. nov. and Haptocallisoma gen. nov., and the description of a new species of Haptocallisoma and a new species of Paracallisoma from the North Atlantic Ocean. An account of all known species within the three genera is given and updated keys to the genera and species are provided. JF - Zootaxa VL - 3995 KW - Amphipoda KW - Atlantic KW - bathyal KW - abyssal KW - necrophage KW - new species KW - Haptocallisoma KW - Paracallisoma KW - Pseudocallisoma SN - 1175-5334 TI - A revision of the genus Paracallisoma Chevreux, 1903 (Crustacea: Amphipoda: Scopelocheiridae: Paracallisominae) with a redescription of the type species of the genus Paracallisoma, the description of two new genera and two new species from the Atlantic Ocean SP - 91 AV - public EP - 132 ER - TY - JOUR ID - soton364734 UR - https://eprints.soton.ac.uk/364734/ IS - 3 A1 - Horton, Tammy A1 - Thurston, Michael H. Y1 - 2014/05/20/ N2 - Two new species of the deep-sea scavenging genus Cyclocaris (Crustacea: Amphipoda) are described from bathyal and abyssal depths in the North and tropical Atlantic Ocean, bringing the total number of species in the genus to four. An account of all four species is given and an updated key to the genus Cyclocaris is provided. JF - Zootaxa VL - 3796 KW - Cyclocaris KW - necrophage KW - Atlantic Ocean KW - bathyal KW - abyssal KW - new species KW - Amphipoda SN - 1175-5334 TI - A revision of the bathyal and abyssal necrophage genus Cyclocaris Stebbing, 1888 (Crustacea: Amphipoda: Cyclocaridae) with the addition of two new species from the Atlantic Ocean SP - 507 AV - none EP - 527 ER - TY - JOUR ID - soton360973 UR - https://eprints.soton.ac.uk/360973/ A1 - Horton, Tammy A1 - Thurston, Michael H. A1 - Duffy, Grant A. Y1 - 2013/12/15/ N2 - This study focussed on a section of the Mid-Atlantic Ridge with one pair of sampling areas at 49°N and the other at 54°N, north and south of the Charlie?Gibbs Fracture Zone and east and west of the ridge, at a water depth of 2500 m. Sixteen baited-trap samples of necrophagous amphipods were collected during three research cruises on the R.R.S. James Cook in 2007, 2009 and 2010. Amphipods of the superfamily Lysianassoidea are numerically dominant and taxonomically diverse and form the most important group of necrophages in most deep-sea environments. A total of 39 scavenging species from 253,306 specimens were identified at the four sampling areas over the 4-year study period. Less than half of the entities could be ascribed to known species. More than 25% of the species recorded were found at all of the sampling areas, supporting the view that necrophagous amphipods are widely distributed animals. The number of lysianassoid species (31) was higher than expected when compared with other studies of necrophagous amphipods, particularly as all sampling was done at one depth (2500 m). Deep-sea scavenging amphipods are generally thought to have low diversity and previous studies have supported this view. Sample sizes were large with some traps containing more than 40,000 specimens. The most abundant species, Abyssorchomene abyssorum, dominated all trap samples with percentage compositions over 90% at the NE sites in 2009?2010. Univariate and Multivariate analyses indicated a significant difference in community composition and species richness between the northern and southern stations. There are at least 15 new species to be described from these samples, and particular effort is required in the genus Paracallisoma and the genus Tryphosella. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 98 KW - Mid-Atlantic Ridge KW - Scavengers KW - Amphipoda KW - Community composition KW - Bathyal-benthic zone SN - 0967-0645 TI - Community composition of scavenging amphipods at bathyal depths on the Mid-Atlantic Ridge SP - 352 AV - none EP - 359 ER - TY - JOUR ID - soton444454 UR - https://eprints.soton.ac.uk/444454/ A1 - Horton, Tammy A1 - Thurston, Michael H. A1 - Vlierboom, Rianna A1 - Gutteridge, Zoe A1 - Pebody, Corinne A. A1 - Gates, Andrew R. A1 - Bett, Brian J. Y1 - 2020/05/01/ N2 - Scavenging amphipods are a numerically dominant and taxonomically diverse group that are key necrophages in deep-sea environments. They contribute to the detrital food web by scavenging large food-falls and provide a food source for other organisms, at bathyal and abyssal depths. Samples of this assemblage have been collected at the Porcupine Abyssal Plain Sustained Observatory (PAP-SO) in the North Atlantic (48°50?N 16°30?W, 4850 m) for >30 years. They were collected by means of baited traps between 1985 and 2016, covering a period of well-characterised changes in the upper ocean. From the 19 samples analysed, a total of 16 taxa were identified from 106,261 specimens. Four taxa, Abyssorchomene chevreuxi (Stebbing, 1906), Paralicella tenuipes Chevreux, 1908, P. caperesca Shulenberger & Barnard, 1976, and Eurythenes spp., dominated catches and were present in all samples. The dominant species varied in time with P. tenuipes typically dominant early in the time series (1985?1997) and its congener, P. caperesca, typically dominant later (2011?2016). Amphipod faunal composition exhibited a significant correlation with the Atlantic Multi-decadal Oscillation (AMO). Amphipod diversity was significantly lower in years with higher estimated volumetric particle flux at 3000 m. Species richness varied significantly between AMO phases, with higher values during ?cool? phase. Our results suggest a ?regime shift? in scavenging amphipod communities following a ?regime shift? in surface ocean conditions driven by a phase shift in Atlantic climate (from cool to warm AMO). This shift manifests itself in a remarkable change in dominant species, from obligate necrophages such as Paralicella spp., with semelparous reproduction to Abyssorchomene spp. which have a more varied diet and iteroparous reproduction, and are thus potentially more able to take advantage of greater or varied food availability from increased organic matter flux to the abyssal seafloor. JF - Progress in Oceanography VL - 184 KW - Atlantic multi-decadal oscillation KW - Benthos KW - Particulate flux KW - Porcupine Abyssal Plain KW - North Atlantic KW - Time series analysis KW - Trap fishing SN - 0079-6611 TI - Are abyssal scavenging amphipod assemblages linked to climate cycles? AV - public ER - TY - JOUR ID - soton8944 UR - https://eprints.soton.ac.uk/8944/ A1 - Houseago-Stokes, R. Y1 - 2000/// JF - International WOCE Newsletter VL - No.38 KW - WOCE KW - NORTH ATLANTIC OCEAN KW - ATLN KW - SATELLITE SENSING KW - EOF KW - TEMPERATURE ANOMALIES KW - EMPIRICAL ORTHOGONAL FUNCTION KW - SURFACE TEMPERATURE KW - NAO KW - NORTH ATLANTIC OSCILLATION KW - CLIMATIC CHANGE EFFECTS TI - Using optimal interpolation and EOF analysis on North Atlantic satellite data SP - 26 AV - none EP - 28 ER - TY - JOUR ID - soton5973 UR - https://eprints.soton.ac.uk/5973/ IS - 10 A1 - Howell, Kerry L. A1 - Billett, David S.M. A1 - Tyler, Paul A. Y1 - 2002/10// N2 - The depth-related distribution of seastar (Echinodermata: Asteroidea) species between 150 and 4950 m in the Porcupine Seabight and Porcupine Abyssal Plain is described. 47 species of asteroid were identified from ~14,000 individuals collected. The bathymetric range of each species is recorded. What are considered quantitative data, from an acoustically monitored epibenthic sledge and supplementary data from otter trawls, are used to display the relative abundance of individuals within their bathymetric range. Asteroid species are found to have very narrow centres of distribution in which they are abundant, despite much wider total adult depth ranges. Centres of distribution may be skewed. This might result from competition for resources or be related to the occurrence of favourable habitats at particular depths. The bathymetric distributions of the juveniles of some species extend outside the adult depth ranges. There is a distinct pattern of zonation with two major regions of faunal change and six distinct zones. An upper slope zone ranges from 150 to ~700 m depth, an upper bathyal zone between 700 and 1100 m, a mid-bathyal zone from 1100 to1700 m and a lower bathyal zone between 1700 and 2500 m. Below 2500 m the lower continental slope and continental rise have a characteristic asteroid fauna. The abyssal zone starts at about 2800 m. Regions of major faunal change are identified at the boundaries of both upper and mid-bathyal zones and at the transition of bathyal to abyssal fauna. Diversity is greatest at ~1800 m, decreasing with depth to ~2600 m before increasing again to high levels at ~4700 m. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 49 KW - asteroidea KW - ecological zonation KW - vertical distribution KW - abyssal plain KW - continental slope KW - n.e. atlantic SN - 0967-0637 TI - Depth-related distribution and abundance of seastars (Echinodermata: Asteroidea) in the Porcupine Seabight and Porcupine Abyssal Plain, N.E. Atlantic SP - 1901 AV - none EP - 1920 ER - TY - JOUR ID - soton13565 UR - https://eprints.soton.ac.uk/13565/ A1 - Hudson, I.R. A1 - Pond, D.W. A1 - Billett, D.S.M. A1 - Tyler, P.A. A1 - Wolff, G.A. Y1 - 2004/// N2 - Fatty acid biomarkers were used to examine the diet of deep-sea holothurians. We collected 3 species from the Porcupine Seabight and Porcupine Abyssal Plain, NE Atlantic, between 800 and 4850 m in August 2001 (summer), March 2002 (pre-spring bloom), and October 2002 (autumn). Of these, 2 species, the abyssal Amperima rosea and the bathyal Bathyplotes natans, showed significant variations in fatty acid compositions. These are likely to be seasonal. Polyunsaturated fatty acids (PUFAs) were dominant within muscle tissue of both species during August 2001 and October 2002, in particular 20:4 (n-6), 20:5 (n-3) and 22:6 (n-3). During March 2002, prior to the spring bloom, there were substantially lower proportions of PUFAs in both species, and increased amounts of mono-unsaturated fatty acids (monoenes), particularly the bacterially-derived biomarkers 18:1 (n-7) and non-methyl uninterrupted dienes (NMIDs). In contrast, the fatty acid composition of the third species, the abyssal Deima validum, remained relatively stable, with muscle tissue containing a high proportion of PUFAs during pre- and post-spring-bloom periods. A further 6 species were sampled in March 2002 and October 2002. Across all these species, 3 patterns of fatty composition were evident: (1) Laetmogone violacea had higher proportions of PUFAs in October than in March; (2) Psychropotes longicauda and Benthogone rosea had lower proportions of PUFAs in October than in March; (3) Deima validum, Oneirophanta mutabilis, Paroriza pallens and P. prouhoi had unchanged fatty acid compositions during these contrasting periods. These differences may be related to the varying reproductive strategies of the species. The implications of changes in fatty acids for reproductive processes, and how these could be factors determining allocation of lipid resources in gonads, is discussed. JF - Marine Ecology Progress Series VL - 281 KW - Holothurian KW - Deep sea KW - Bentho-pelagic coupling KW - Seasonal flux KW - NE Atlantic KW - Lipids TI - Temporal variations in fatty acid composition of deep-sea holothurians: evidence of bentho-pelagic coupling SP - 109 AV - none EP - 120 ER - TY - JOUR ID - soton14882 UR - https://eprints.soton.ac.uk/14882/ IS - 1-4 A1 - Huehnerbach, V. A1 - Masson, D.G. Y1 - 2004/// N2 - A unique and comprehensive collection of submarine landslide data from different tectonic environments in the North Atlantic, based on published literature and industry sources, is analysed in order to establish possible relationships between landslide parameters and evaluate their potential importance. Slope failures in the western North Atlantic appear to be more frequent, and apart from a few huge failure complexes, on average smaller than those found in the eastern North Atlantic. On the other hand, failures tend to occur on lower slopes in the eastern North Atlantic. This trend could be used to conclude information about the sediment strata of the landslides in these two areas; long slides seem to consist of softer, more fluid, material, whereas short failures might contain of more stiff sediments. It is also found that a majority of failures on both sides of the Atlantic are generated in a water depth window between 1000 and 1300 m, bringing internal waves and/or gas hydrates into play as possible contributing factors. Failures in fjords are generally influenced and limited by the geometry of the environment they occur in. JF - Marine Geology VL - 213 KW - slope failures KW - statistics KW - database KW - North Atlantic KW - COSTA project SN - 0025-3227 TI - Landslides in the North Atlantic and its adjacent seas: an analysis of their morphology, setting and behaviour SP - 343 AV - none EP - 362 ER - TY - RPRT N1 - Abstract deposited at the request of B.J.Bett. Any request to view the whole document should be directed to him - contact details included in abstract. ID - soton48597 UR - https://eprints.soton.ac.uk/48597/ A1 - Hughes, J.A. A1 - Bett, B.J. Y1 - 2007/10/02/ N2 - This report details seabed observations carried out on behalf of BP Angola for an environmental survey of Angola Blocks 18 and 31 (bathyal SE Atlantic). Seabed photography (still and video) was undertaken with the NOC WASP vehicle. The WASP deployments spanned water depths of 1550-2050m over the Angolan Margin and included studies on the open continental slope and on and around seabed pockmarks and salt diapirs. The shallower sites (Block 18; 1550-1650m) were dominated by small elpidiid holothurians. At intermediate depths (Block 31; c. 1800m) the megabenthos was dominated by the holothurian Scotoplanes globosa. The deeper sites (Block 31 >1900m) were dominated by the spatangoid urchin Pourtalesia alcocki. Two ?local variant? faunas were recognized; one associated with the elevated topography of salt diapirs and dominated by ophiuroids. The other from a large seabed pockmark with a highly abundant population of Pourtalesia alcocki (mean abundance 39.56 10m-2; maximum 108.88 10m-2) and also notable for the presence of fragments of cemented sediment, large numbers of dead bivalve tests (including Vesicomyidae Calyptogena-type), squat lobsters (Munidopsis sp.), a bacterial mat and a possible tubeworm (? Siboglinidae). All the latter observations suggest the possibility of fluid flow / cold seep conditions in the vicinity of the pockmark.

Should you wish to consult or cite this report please contact the author directly (Brian Bett, bjb@noc.soton.ac.uk, +44 (0)23 80596355).
PB - National Oceanography Centre T3 - 29 KW - Angola KW - Angolan Margin KW - bathyal KW - benthos KW - BP KW - chemosynthetic communities KW - continental slope KW - photography KW - pockmarks KW - Portalesia KW - salt diapirs KW - Scotoplanes KW - SE Atlantic KW - seabed KW - sediments KW - Siboglinidae KW - tubeworms KW - videotape recording KW - WASP M1 - project_report TI - Angola Block 18WAD and Block 31 pre-operational environmental survey, October 2005: analysis of seabed images taken using WASP (Wide-Angle Seabed Photography) AV - none EP - 40 ER - TY - JOUR ID - soton2173 UR - https://eprints.soton.ac.uk/2173/ A1 - Hughes, J.A. A1 - Gooday, A. A1 - Murray, J.W. Y1 - 2003/// JF - Newsletter of Micropalaeontology VL - No. 68 KW - ATLNE KW - BENTHIC FORAMINIFERA KW - NORTH EAST ATLANTIC OCEAN KW - ORGANIC CARBON KW - ECOLOGICAL ASSOCIATIONS KW - BENBO KW - DEEP OCEAN KW - BENTHIC BOUNDARY LAYER KW - GEOLOGY KW - BIOLOGY TI - The preservation potential of benthic foraminiferal assemblages at three deep-sea sites in the northeast Atlantic AV - none ER - TY - JOUR ID - soton209075 UR - https://eprints.soton.ac.uk/209075/ IS - 5 A1 - Hughes, S. A1 - Holliday, N.P. A1 - Gaillard, F. A1 - ICES Working Group on Oceanic Hydrography, Y1 - 2012/07// N2 - The ICES Report on Ocean Climate presents the latest information on the status and trends of sea temperature and salinity in the North Atlantic and Nordic Seas. It is the main product of the ICES Working Group on Oceanic Hydrography, published annually. Bringing together multiple time-series from across the ICES and NAFO regions offers insight into the concurrent spatial and temporal trends in ocean temperature and salinity. This paper presents an overview of the physical variability in the North Atlantic Ocean at decadal and longer time-scales and reviews the current state of understanding of the causes and mechanisms of this variability. Between the 1960s and the 1990s, the North Atlantic Oscillation (NAO) index increased from a persistent negative phase in the 1960s to a strong positive phase during the 1980s and early 1990s. However, during the decade 2000?2009, because of shifts in atmospheric pressure patterns, the NAO was weak and the NAO index was not a good indicator of atmospheric forcing. Marked changes were also observed in oceanographic indices such as the Subpolar Gyre index during the mid-1990s and, as a consequence, conditions in the decade 2000?2009 have been very different from those of the previous four decades. JF - ICES Journal of Marine Science VL - 69 KW - circulation KW - multidecadal variability KW - North Atlantic KW - salinity KW - temperature SN - 1054-3139 TI - Variability in the ICES/NAFO region between 1950 and 2009: observations from the ICES Report on Ocean Climate SP - 706 AV - none EP - 719 ER - TY - RPRT ID - soton196895 UR - https://eprints.soton.ac.uk/196895/ Y1 - 2011/08// PB - International Council for the Exploration of the Sea T3 - 309 Special Issue KW - ocean climate KW - north atlantic KW - time series observations SN - 1017-6195 ED - Hughes, S.L. ED - Holliday, N.P. ED - Beszczynska-Moller, A. M1 - project_report TI - ICES Report on Ocean Climate 2010 AV - none EP - 73 ER - TY - RPRT N1 - Deposited by Jane Conquer ID - soton63640 UR - https://eprints.soton.ac.uk/63640/ Y1 - 2008/08// PB - International Council for the Exploration of the Sea T3 - 291 Special Issue KW - ocean climate KW - north atlantic KW - time series observations ED - Hughes, S.L. ED - Holliday, N.P. ED - Beszczynska-Moller, A. M1 - project_report TI - ICES report on ocean climate 2007 AV - none EP - 62 ER - TY - RPRT ID - soton48777 UR - https://eprints.soton.ac.uk/48777/ A1 - Hughes, Sarah L. A1 - Holliday, Naomi P. Y1 - 2007/// PB - International Council for the Exploration of the Sea T3 - 289 Special Issue KW - ocean climate KW - north atlantic KW - time series observations M1 - project_report TI - ICES report on ocean climate 2006 AV - none EP - 57 ER - TY - RPRT ID - soton42359 UR - https://eprints.soton.ac.uk/42359/ A1 - Hughes, Sarah L. A1 - Holliday, Naomi P. Y1 - 2006/// PB - International Council for the Exploration of the Sea T3 - 280 KW - ocean climate KW - north atlantic KW - time series observations M1 - project_report TI - ICES report on ocean climate 2005 AV - none EP - 47 ER - TY - JOUR ID - soton58560 UR - http://www.agu.org/pubs/crossref/2002/2001GC000284.shtml IS - 8 A1 - Humphris, S.E. A1 - Fornari, D.J. A1 - Scheirer, D.S. A1 - German, C.R. A1 - Parson, L.M. Y1 - 2002/// N2 - We have investigated the relations between volcanic, tectonic, and hydrothermal activity on Lucky Strike Seamount (37°17?N, Mid-Atlantic Ridge) using a nested survey strategy involving collection of data from different deep-sea mapping systems. The highly tectonized seamount summit consists of three volcanic cones surrounding a relatively flat depression with a young lava lake in its center. Hydrothermal activity is focused mainly within the summit depression with most of the vents located proximal to the lava lake. Isolated active and inactive chimneys and mounds are widespread throughout the summit depression and occur on both volcanic (pillow lava) and hydrothermal (sulfide rubble and hydrothermally cemented breccias) substrates. The large volume of sulfide rubble, together with the nature of the sulfide structures, indicates that hydrothermal activity has been episodic but ongoing for a long period of time (hundreds to thousands of years). On the basis of the distribution of hydrothermal deposits, we propose a model of alternation between tectonic and volcanic control on hydrothermalism at Lucky Strike Seamount. Midsegment melt focusing produces a spatially and temporally stable heat source that sustains focused high-temperature hydrothermal activity over long time periods. During periods of amagmatic extension, active faulting within the summit depression provides multiple, near-surface fluid flow pathways for discharge of high-temperature fluids and widespread deposition of massive sulfides. During eruptive events, rapid effusion of very hot lava creates a lava lake and hyaloclastite deposits. The new sheet flows form a cap on the hydrothermal system, and fluid upflow is reorganized. Discharge of high-temperature fluids is restricted to isolated sites with relatively high permeability, for example, the edges of the lava lake. Much of the upwelling hydrothermal fluid pools in the subsurface, conductively cools, and mixes with entrained seawater before discharging as widespread low-temperature diffuse flow. Hyaloclastites become cemented, further augmenting the sealing of the system. Present-day activity at Lucky Strike Seamount represents this locally volcanically controlled phase of activity, despite the segment as a whole being dominantly amagmatic.
JF - Geochemistry, Geophysics, Geosystems VL - 3 KW - Lucky Strike KW - Mid-Atlantic Ridge KW - hydrothermal activity KW - sulfides KW - volcanic-tectonic controls SN - 1525-2027 TI - Geotectonic setting of hydrothermal activity on the summit of Lucky Strike Seamount (37,17'N, Mid-Atlantic Ridge) AV - none ER - TY - JOUR ID - soton347546 UR - https://eprints.soton.ac.uk/347546/ A1 - Hunt, F.K. A1 - Hirschi, J.J-M. A1 - Sinha, Bablu A1 - Oliver, Kevin A1 - Wells, Neil Y1 - 2013/07/23/ N2 - We use a new method based on point correlation maps and self-organising maps (SOMs) to identify teleconnection patterns in 60 yr of National Centres for Environmental Prediction/National Centre for Atmospheric Research (NCEP/NCAR) sea level pressure (SLP) re-analysis data. The most prevalent patterns are the El Nino Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO) and the Southern Annular Mode (SAM). Asymmetries are found between base points in opposite centres of action of the NAO and the Pacific North America pattern (PNA). The SOM-based method is a powerful tool that allows us to efficiently assess how realistically teleconnections are reproduced in any climate model. The degree of agreement between modelled and re-analysis-based teleconnections (or between different models) can be summarised in a single plot. Here, we illustrate this by assessing the skill of the medium complexity climate model FORTE (Fast Ocean Rapid Troposphere Experiment). FORTE reproduces some realistic teleconnections, such as the Arctic Oscillation (AO), the NAO, the PNA, the SAM, the African Monsoon and ENSO, along with several other teleconnections, which resemble to varying degrees the corresponding NCEP patterns. However, FORTE tends to underestimate the strength of the correlation patterns and the patterns tend to be slightly too zonal. The accuracy of frequency of occurrence is variable between patterns. The Indian Ocean is a region where FORTE performs poorly, as it does not reproduce the teleconnection patterns linked to the Indian Monsoon. In contrast, the North and equatorial Pacific and North Atlantic are reasonably well reproduced. JF - Tellus A VL - 65 KW - teleconnections KW - self-organising map KW - climate model KW - North Atlantic Oscillation KW - El Nino Southern Oscillation KW - empirical orthogonal function SN - 0280-6495 TI - Combining point correlation maps with self-organising maps to compare observed and simulated atmospheric teleconnection patterns AV - public ER - TY - RPRT ID - soton69695 UR - https://eprints.soton.ac.uk/69695/ A1 - Huvenne, V.A.I. Y1 - 2009/11// N2 - James Cook cruise 035 was aimed at the detailed mapping of the Whittard Canyon system along the Celtic Margin (NE Atlantic). In 12 days, >700 km of track-lines were surveyed with the Towed Ocean Bottom Instrument (TOBI, carrying a 30 kHz sidescan sonar system with phase bathymetry capability, an 8 kHz chirp profiler and a magnetometer) and 6130 km2 of shipborne multibeam data was acquired over the 4 main branches of the canyon. This comprehensive and highly detailed dataset will provide new insights in canyon morphology, formation, sediment transport processes and into the resulting spatial distribution of benthic habitats. In addition, the data formed an indispensable base map for the planning of ROV dives during the follow-on cruise JC036.
PB - National Oceanography Centre T3 - 42 KW - Celtic Margin KW - cruise 35 2009 KW - HERMIONE KW - James Cook KW - OCEANS 2025 KW - NE Atlantic KW - submarine canyons KW - TOBI KW - Whittard Canyon M1 - project_report TI - RRS James Cook Cruise 35, 7-19 Jun 2009. Sidescan sonar mapping of the Whittard Canyon, Celtic Margin AV - public EP - 35 ER - TY - JOUR ID - soton69550 UR - https://eprints.soton.ac.uk/69550/ IS - 12 A1 - Huvenne, Veerle Ann Ida A1 - Van Rooij, David A1 - De Mol, Ben A1 - Thierens, Mieke A1 - O?Donnell, Rory A1 - Foubert, Anneleen Y1 - 2009/12// N2 - IODP Expedition 307, targeting the 160 m high Challenger Mound and its surroundings in the Porcupine Seabight, NE Atlantic, was the first occasion of scientific drilling of a cold-water coral carbonate mound. Such mound structures are found at several locations along the continental margin but are especially numerous off Ireland. All rooted on a common unconformity (RD1) and embedded in drift sediments, the mounds in the Porcupine Seabight remain enigmatic structures, and their initial trigger and formation mechanisms are still not entirely clear. This paper discusses the sedimentary environment during the initial stages of Challenger Mound, and at the start-up of the embedding sediment drift. The results are interpreted within the regional palaeo-environmental context. Based on detailed grain-size analyses and planktonic foraminifera assemblage counts, a 14-m interval overlying the regional base-of-mound unconformity RD1 is characterised at IODP Sites U1317 (on mound), U1316 (off mound), and U1318 (background site). Several sedimentary facies are identified and interpreted in relation to regional current dynamics. Using the foraminifera counts, existing age models for the initial stages of on-mound and off-mound sedimentation are refined. Sedimentation within the initial mound was characterised by a two-mode system, with the observed cyclicities related to glacial/interglacial stages. However, the contrast in environmental conditions between the stages was less extreme than observed in the most recent glacial/interglacial cycles, allowing continuous cold-water coral growth. This sustained presence of coral framework was the key factor for fast mound build-up, baffling sediments at periods of slack currents, and protecting them from renewed erosion during high-current events. The off-mound and background sedimentation consisted mainly of a succession of contourite beds, ranging from sandy contourites in the initial stages to muddy contourites higher up in the sequence, representing the true onset of drift sedimentation. The latter illustrate the increasing importance of glacial conditions after the Mid-Pleistocene Revolution. The overall findings are summarised in a descriptive conceptual model. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 56 KW - Cold-water corals KW - Carbonate mounds KW - Sediment dynamics KW - Planktonic foraminifera assemblages KW - Grain size KW - NE Atlantic SN - 0967-0637 TI - Sediment dynamics and palaeo-environmental context at key stages in the Challenger cold-water coral mound formation: Clues from sediment deposits at the mound base SP - 2263 AV - none EP - 2280 ER - TY - RPRT N1 - Deposited at authors request. ID - soton350263 UR - https://eprints.soton.ac.uk/350263/ A1 - Hydes, D.J. A1 - Hartman, M.C. A1 - Campbell, J.M. A1 - Jiang, Z-P. A1 - Hartman, S.E. A1 - Pagnani, M. A1 - Kelly-Gerreyn, B.A. A1 - Donahoe, J. Y1 - 2013/03// N2 - The ocean plays a major role in controlling the concentration of carbon dioxide (CO2) in the atmosphere. Increasing concentrations of CO2 in the atmosphere are a threat to the stability of the earth?s climate. A better understanding of the controlling role of the ocean will improve predictions of likely future changes in climate and the impact of the uptake of CO2 itself on marine eco-systems caused by the associated acidification of the ocean waters. The SNOMS Project (SWIRE NOCS Ocean Monitoring System) is a ground breaking joint research project supported by the Swire Group Trust, the Swire Educational Trust, the China Navigation Company (CNCo) and the Natural Environment Research Council. It collects high quality data on concentrations of CO2 in the surface layer of the ocean. It contributes to the international effort to better quantify (and understand the driving processes controlling) the exchanges of CO2 between the ocean and the atmosphere.

In 2006 and 2007 a system that could be used on a commercial ship to provide data over periods of several months with only limited maintenance by the ships crew was designed and assembled by NOCS. The system was fitted to the CNCo ship the MV Pacific Celebes in May 2007. The onboard system was supported by web pages that monitored the progress of the ship and the functioning of the data collection system. To support the flow of data from the ship to the archiving of the data at the Carbon Dioxide Information Analysis Center (CDIAC in the USA) data processing procedures were developed for the quality control and systematic handling of the data. Data from samples of seawater collected by the ships crew and analysed in NOC (730 samples) have been used to confirm the consistency of the data from the automated measurement system on the ship.

To examine the data collected between 2007 and 2012 the movements of the ship are divided into 16 voyages. Initially The Celebes traded on a route circum-navigating the globe via the Panama and Suez Canals. In 2009 the route shifted to one between Australia and New Zealand to USA and Canada. Analysis of the data is an on going process. It has demonstrated that the system produces reliable data. Data are capable of improving existing estimates of seasonal variability. The work has improved knowledge of gas exchange processes. Data from the crew-collected-samples are helping improve our ability to estimate alkalinity in different areas. This helps with the study of ocean acidification. Data from the 9 round trips in the Pacific are currently being examined along with data made available by the NOAA-PMEL laboratory forming time series from 2004 to 2012. The data from the Pacific route are of considerable interest. One reason is that the data monitors variations in the fluxes of CO2 associated with the current that flows westwards along the equator. This is one of the major natural sources of CO2 from the ocean into the atmosphere. PB - National Oceanography Centre T3 - 33 KW - Ocean KW - Global Pacific KW - Atlantic KW - Carbon Dioxide KW - Fluxes KW - Methods KW - Commercial Ships KW - 2007 to 2012 M1 - project_report TI - Report of the SNOMS Project 2006 to 2012, SNOMS SWIRE NOCS Ocean Monitoring System. Part 1: Narrative description AV - public EP - 40 ER - TY - RPRT N1 - Deposited at authors request. ID - soton376356 UR - https://eprints.soton.ac.uk/376356/ A1 - Hydes, D.J. A1 - Hartman, M.C. A1 - Campbell, J.M. A1 - Jiang, Z-P. A1 - Hartman, S.E. A1 - Pagnani, M. A1 - Kelly-Gerreyn, B.A. A1 - Donahoe, J. Y1 - 2013/03// N2 - The SNOMS Project (SWIRE NOCS Ocean Monitoring System) is a ground breaking joint research project supported by the Swire Group Trust, the Swire Educational Trust, the China Navigation Company (CNCo) and the Natural Environment Research Council. The project was designed to gather high quality data on concentrations of carbon dioxide in the surface layer of the ocean. It contributes to the international effort to better quantify (and understand the driving processes controlling) the exchanges of CO2 between the ocean and the atmosphere. In 2006 and 2007 a system that could be used on a commercial ship to provide data over periods of several months with only limited maintenance by the ships crew was designed and built by the National Oceanography Centre in Southampton (NOCS). The system was fitted to the CNCo ship the MV Pacific Celebes in May 2007. This part of the report contains the annexes that document in detail the system design and implementation and fitting-out on board the Celebes. They detail the tasks carried out by the crew and NOC scientists and their colleagues on shore both in terms of scientific and outreach activities. They also contain plots of raw and processed data. The first annex provides maps of the routes taken by the ship. These begin and end at the ports were the ships was visited for servicing the system. Annex 2 contains copies of the proposals written by NOC to the Swire Group Trust and Swire Educational Trust and of the resulting contracts. The third annex compiles into one place the technical reports written describing the design and operation of the system and a report that describes the system that was developed to manage the large quantities data produced by the system, taking it from the raw data collected by the ship to data that had been quality controlled. Annex 4 provides graphical presentation of the data. The first section provides plots of the calibrated data on concentrations CO2 across the Pacific and compares data from the sensors and the water samples that were collected by the ships crew. Section two shows plots of the raw data from the sensors, it is important that these plots are accessible as they provide ready access to future users of the SNOMS or similar systems for them to make comparisons to the performance of their systems to that achieved by the SNOMS system. Section three provides the salinity calibration plots. As basic oceanographic data it is important that the performance of the sensors used to acquire the salinity data are traceable. Annex 5 provides listings of the various outreach activities related to the work of the SNOMS project covering scientific papers and presentations, copies of some of the presentations and information on approaches to other shipping companies and foundations for increased support. The final annex is simple table recording the periods of use of the 34 individual sensors used on the Pacific Celebes between 2007 and 2012. PB - National Oceanography Centre T3 - 34 KW - Ocean KW - Global Pacific KW - Atlantic KW - Carbon Dioxide KW - Fluxes KW - Methods KW - Commercial Ships KW - 2007 to 2012 M1 - project_report TI - Report of the SNOMS Project 2006 to 2012, SNOMS SWIRE NOCS Ocean Monitoring System. Part 2: Detailed technical and data annexes AV - restricted EP - 443 ER - TY - JOUR ID - soton8019 UR - https://eprints.soton.ac.uk/8019/ IS - 14/15 A1 - Hydes, D.J. A1 - Le Gall, A.C. A1 - Holley, S. Y1 - 2001/// N2 - As part of the OMEX I project, nutrient determinations were made on 17 cruises in the region of the Goban Spur and La Chapelle Bank between 46 and 51°N, in all seasons of the year, between 1993?1995. Over this period no change was detectable in the structure of the water masses below the deep winter mixed layer. The N : P (dissolved nitrate-to-phosphate) ratio changed from 16 at 100-m depth to less than 15 at 3300-m depth. At intermediate depths nutrient and oxygen data indicate the presence of Mediterranean Outflow water overlying Labrador Sea Water at its most eastern extension. Estimated maximum levels of production in the spring bloom are the total N-limited new primary production equivalent between 24 and 41 gC m?2, the equivalent maximum diatom production is 11 gC m?2. Measurements during the spring bloom suggest a conversion factor of 1 M nitrate to 1 g l?1 chlorophyll, at the shelf break, which is consistent with other recent measurements in European shelf seawaters. Sediment trap data suggest that 80% (5.4 g m?2) of the opal produced in the spring bloom dissolved before reaching the sediment trap at 600 m. A comparison of the winter and summer profiles for dissolved silicon suggests a similar dissolution of 9±3 g opal m?2 above 300-m depth. Measurements of dissolved organic carbon (DOC) in September 1994 show an enrichment of 7 M-C above the seasonal thermocline relative to the winter values (52±4 M). In winter dissolved organic nitrogen represents 40% of the pool of total dissolved nitrogen. There is no consistent evidence of an increase in the concentration of DON during summer. Measurements of nitrate in surface waters in January 1994 show that concentrations off-shelf vary with the temperature of the water and are related to the depth of winter mixing. Mixing in surface waters is discontinuous at the shelf break, demonstrating the degree to which exchange across the shelf break is limited even in winter. OMEX winter measurements of nitrate concentrations can be used to estimate the flow of water across the shelf break that would be required to maintain the nitrogen balance in the North Sea at a steady state. The estimate is 0.6 Sv (1 Sv=106 m3 s?1), which is similar to an earlier estimate of a total flow of 1.7 Sv based on salt budgets (cf. Huthnance, Deutsche Hydrographische Zeitschrift, 49 (1997) 153). JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 48 KW - OMEX KW - SHELF DYNAMICS KW - NORTHEAST ATLANTIC OCEAN KW - DISSOLVED ORGANIC MATTER SN - 0967-0645 TI - Supply and demand of nutrients and dissolved organic matter at and across the NW European shelf break in relation to hydrography and biogeochemical activity SP - 3023 AV - none EP - 3047 ER - TY - JOUR ID - soton189483 UR - https://eprints.soton.ac.uk/189483/ IS - 23-24 A1 - Ingels, Jeroen A1 - Billett, David S.M. A1 - Kiriakoulakis, Konstadinos A1 - Wolff, George A. A1 - Vanreusel, Ann Y1 - 2011/12/01/ N2 - Samples collected at two different depths (ca. 3200 and ca. 4200 m) in the Setúbal and Cascais canyons off the Portuguese coast, during the HERMES RRS Charles Darwin cruise CD179, were analysed for (1) sediment biogeochemistry (TOC, TN) and (2) composition, and structural and trophic diversity of nematode communities. Multivariate PERMANOVA analysis on the nematode community data revealed differences between sediment layers that were greater than differences between canyons, water depths, and stations. This suggests that biogeochemical gradients along the vertical sediment profile are crucial in determining nematode community structure. The interaction between canyon conditions and the nematode community is illustrated by biogeochemical patterns in the sediment and the prevalence of nematode genera that are able to persist in disturbed sediments. Trophic analysis of the nematode community indicated that non-selective deposit feeders are dominant, presumably because of their non-selective feeding behaviour compared to other feeding types, which gives them a competitive advantage in exploiting lower-quality food resources. This study presents a preliminary conceptual scheme for interactions between canyon conditions and the resident fauna. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 58 KW - Submarine canyons KW - NE Atlantic KW - Western Iberian Margin KW - Deep sea KW - Meiofauna KW - Nematodes KW - Biogeochemistry KW - Trophic Diversity KW - Community Structure KW - Conceptual Scheme KW - Canyon-Fauna Interaction SN - 0967-0645 TI - Structural and functional diversity of Nematoda in relation with environmental variables in the Setúbal and Cascais canyons, Western Iberian Margin SP - 2354 AV - none EP - 2368 ER - TY - JOUR ID - soton349141 UR - https://eprints.soton.ac.uk/349141/ A1 - Ivanovic, Ruza F. A1 - Valdes, Paul J. A1 - Flecker, Rachel A1 - Gregoire, Lauren J. A1 - Gutjahr, Marcus Y1 - 2013/02// N2 - Multiple palaeo-proxy and modelling studies suggest that Mediterranean Outflow Water (MOW) is an important driver of Atlantic Meridional Overturning Circulation (AMOC), particularly during periods of weak overturning. Here, we employ the HadCM3 ocean?atmosphere General Circulation Model (GCM) to investigate the effect of using different parameterisations of Mediterranean?Atlantic water exchange on global ocean circulation and climate. In HadCM3, simulating flow through the Gibraltar Straits with an ?open seaway? rather than a ?diffusive pipe? causes a shoaling and strengthening of the MOW plume. This reorganises shallow Atlantic circulation, producing regional surface air temperature anomalies of up to + 11 °C and ?7.5 °C. We conclude that when investigating the influence of MOW on modelled ocean circulation and climate, an accurate parameterisation of Mediterranean?Atlantic exchange is important and should match observed fresh water and salinity flux constraints. This probably cannot be achieved through a simple ?diffusive pipe? with depth invariant mixing coefficient. JF - Ocean Modelling VL - 62 KW - Marine gateway KW - Gibraltar Straits KW - Mediterranean outflow KW - North Atlantic circulation KW - Atlantic Meridional Overturning Circulation SN - 1463-5003 TI - The parameterisation of Mediterranean?Atlantic water exchange in the Hadley Centre model HadCM3, and its effect on modelled North Atlantic climate SP - 11 AV - none EP - 16 ER - TY - JOUR ID - soton432864 UR - https://eprints.soton.ac.uk/432864/ IS - 13 A1 - Jacobs, Zoe L. A1 - Grist, Jeremy P. A1 - Marsh, Robert A1 - Josey, Simon A. Y1 - 2019/07/16/ N2 -

The transport of warm, saline subtropical water to the subpolar gyre (SPG) in the North Atlantic has been the subject of a range of Lagrangian studies, establishing intergyre exchange on timescales of 2?7 years, with greater subsurface throughflow. Here calculating particle trajectories in a high-resolution, global hindcast, we present new evidence for a direct, subsurface pathway to the SPG from the Gulf Stream (GS) on subannual timescales. The pathway is most evident for particles initially at 200-m depth in the GS and is enhanced after a prolonged period of positive North Atlantic Oscillation. This occurred in the mid-1990s and led to warming and salinification of the western SPG consistent with observations. The more realistic advective pathways and timescales in the high-resolution model enable, for the first time, attribution of temperature and salinity changes in the SPG to a direct influx of GS water.

JF - Geophysical Research Letters VL - 46 KW - climate KW - Gulf Stream KW - Lagrangian KW - model KW - North Atlantic KW - ocean SN - 0094-8276 TI - A subannual subsurface pathway from the Gulf Stream to the Subpolar Gyre and its role in warming and salinification in the 1990s SP - 7518 AV - public EP - 7526 ER - TY - JOUR ID - soton9827 UR - http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6V61-4BX7BGB-5-H&_cdi=5801&_orig=browse&_coverDate=04%2F30%2F2004&_sk=997789998&view=c&wchp=dGLbVzb-zSkWW&_acct=C000010399&_version=1&_userid=126770&md5=74b91144705b2237ead1fcea0d5c0e75&ie=f.pdf IS - 1-4 A1 - Jean-Baptiste, P. A1 - Fourre, E. A1 - Charlou, J. A1 - Radford-Knoery, J. A1 - German, C.R. Y1 - 2004/// N2 - The 3He/4He ratio and helium concentration have been measured in the vent fluids and the dispersing plume of the Rainbow hydrothermal site, on the Mid-Atlantic Ridge (MAR). The 3He/4He ratio (7.51 Ra) and 3He end-member concentration (25 pmol/kg) are in the range of observed values elsewhere on mid-ocean ridges, pointing to the relative homogeneity of the upper mantle with respect to helium isotope geochemistry. 3He is linearly correlated with methane and manganese throughout the plume, with CH4/3He and Mn/3He ratios identical to those measured in the hot fluids. The bulk residence time of the plume in the rift valley estimated from the plume 3He budget is V20 days. The 3He flux transported by the plume, calculated from current-meter data, is 12.3: 3 nmol/s, requiring a flux of 490 kg/s of high-temperature fluid. The scaling of the heat flux emitted by the Rainbow site to that of 3He, using the 3He/heat ratio measured in the hydrothermal fluids (9.3 :2U10318 mol/J), indicates a heat output of 1320 MW. With a regional spreading rate of V25 mm/year, we calculate that the annual 3He flux for this section of the MAR is of the order of 0.5:0.2 mmol per kilometre of ridge per millimetre of newly formed crust. This figure compares well with the flux calculated for the neighbouring Lucky Strike segment. Although the uncertainties remain large, both fluxes are V40-50% above the world average (0.33 mmol/km/mm), thus supporting earlier suggestions that the intensity of the hydrothermal activity south of the Azores is higher than expected from the regional spreading rate. JF - Earth and Planetary Science Letters VL - 221 KW - helium KW - hydrothermal vents KW - isotopes KW - heat flux KW - Mid-Atlantic Ridge SN - 0012-821X TI - Helium isotopes at the Rainbow hydrothermal site (Mid-Atlantic Ridge 36,14'N) SP - 325 AV - none EP - 335 ER - TY - JOUR ID - soton8959 UR - https://eprints.soton.ac.uk/8959/ IS - 3 A1 - Jia, Y. Y1 - 2000/// JF - CLIVAR Exchanges VL - 5 KW - WOCE KW - CMIP KW - ATLANTIC OCEAN KW - HEAT TRANSPORT KW - OVERTURNING TI - The ocean heat transport and meridional overturning near 25 degrees North in the Atlantic in the CMIP models SP - 23 AV - none EP - 26 ER - TY - JOUR ID - soton350714 UR - https://eprints.soton.ac.uk/350714/ IS - 2 A1 - Jiang, Zong-Pei A1 - Hydes, David J. A1 - Tyrrell, Toby A1 - Hartman, Sue A1 - Hartman, Mark C. A1 - Dumousseaud, Cynthia A1 - Padin, Xose Antonio A1 - Skjelvan, Ingunn A1 - González-Pola, César Y1 - 2013/02// N2 - Biogeochemical variations of surface water in the Northeast Atlantic (Bay of Biscay) were examined using high-frequency underway measurements combined with monthly sampling of carbon-related variables. The mechanisms controlling seasonal CO2 variability were investigated by distinguishing the contributions of biological and physical processes to the monthly changes in dissolved inorganic carbon (DIC) and partial pressure of CO2 (pCO2). The seasonality of DIC (47?81?µmol?kg?1) had a single peak with a winter maximum primarily driven by vertical mixing and a summer minimum driven by spring biological removal. Non-Redfield C:N uptake was observed in the nutrient-depleted summer but not during the spring bloom. In the North Atlantic, pCO2 seasonality shows a latitudinal transition: from the temperature-dominated oligotrophic subtropical gyre to the subpolar region where pCO2 is dominated by changing concentrations of DIC. In the midlatitude Bay of Biscay, the annual cycle of pCO2 (61?75 µatm) showed a double-peak distribution. The summer pCO2 peak was mainly driven by temperature increase, while the winter peak resulted from the dominant effect of entrainment of subsurface water. Interannual variations of DIC were more pronounced in winter and were driven by the changes in the strength of winter mixing. Higher wintertime concentrations and seasonal amplitudes of DIC were observed in cold years when the mixed-layer depths were deeper, which appears to be associated with negative phases of the North Atlantic Oscillation. The Bay of Biscay shows a decrease of CO2 uptake in 2008?2010 (?0.97 and ?0.75?mol?m?2?yr?1) compared to 2002?2004 (?1.47 and ?1.68?mol?m?2?yr?1). JF - Journal of Geophysical Research VL - 118 KW - seasonal KW - interannual KW - carbonate system KW - CO2 flux KW - North Atlantic KW - Bay of Biscay SN - 0148-0227 TI - Key controls on the seasonal and interannual variations of the carbonate system and air-sea CO2 flux in the Northeast Atlantic (Bay of Biscay) SP - 785 AV - public EP - 800 ER - TY - JOUR ID - soton190085 UR - https://eprints.soton.ac.uk/190085/ IS - 10 A1 - Johns, W.E. A1 - Baringer, M.O. A1 - Beal, L.M. A1 - Cunningham, S.A. A1 - Kanzow, T. A1 - Bryden, H.L. A1 - Hirschi, J.J.M. A1 - Marotzke, J. A1 - Meinen, C.S. A1 - Shaw, B. A1 - Curry, R. Y1 - 2010/05// N2 - Continuous estimates of the oceanic meridional heat transport in the Atlantic are derived from the Rapid Climate Change?Meridional Overturning Circulation (MOC) and Heatflux Array (RAPID?MOCHA) observing system deployed along 26.5°N, for the period from April 2004 to October 2007. The basinwide meridional heat transport (MHT) is derived by combining temperature transports (relative to a common reference) from 1) the Gulf Stream in the Straits of Florida; 2) the western boundary region offshore of Abaco, Bahamas; 3) the Ekman layer [derived from Quick Scatterometer (QuikSCAT) wind stresses]; and 4) the interior ocean monitored by ?endpoint? dynamic height moorings. The interior eddy heat transport arising from spatial covariance of the velocity and temperature fields is estimated independently from repeat hydrographic and expendable bathythermograph (XBT) sections and can also be approximated by the array.

The results for the 3.5 yr of data thus far available show a mean MHT of 1.33 ± 0.40 PW for 10-day-averaged estimates, on which time scale a basinwide mass balance can be reasonably assumed. The associated MOC strength and variability is 18.5 ± 4.9 Sv (1 Sv ? 106 m3 s?1). The continuous heat transport estimates range from a minimum of 0.2 to a maximum of 2.5 PW, with approximately half of the variance caused by Ekman transport changes and half caused by changes in the geostrophic circulation. The data suggest a seasonal cycle of the MHT with a maximum in summer (July?September) and minimum in late winter (March?April), with an annual range of 0.6 PW. A breakdown of the MHT into ?overturning? and ?gyre? components shows that the overturning component carries 88% of the total heat transport. The overall uncertainty of the annual mean MHT for the 3.5-yr record is 0.14 PW or about 10% of the mean value. JF - Journal of Climate VL - 24 KW - Atlantic Ocean KW - Meridonial overturning circulation KW - Sea surface temperature KW - Transport KW - Anomalies SN - 0894-8755 TI - Continuous, array-based estimates of Atlantic Ocean heat transport at 26.5 °N SP - 2429 AV - none EP - 2449 ER - TY - JOUR ID - soton8897 UR - https://eprints.soton.ac.uk/8897/ IS - 1 A1 - Jollivet, D. A1 - Empis, A. A1 - Baker, M.C. A1 - Hourdez, S. A1 - Comtet, T. A1 - Jouin-Toulmond, C. A1 - Desbruyeres, D. A1 - Tyler, P.A. Y1 - 2000/// JF - Journal of the Marine Biological Association of the United Kingdom VL - 80 KW - POLYCHAETES KW - HYDROTHERMAL COMMUNITIES KW - POPULATION STRUCTURE KW - REPRODUCTION KW - LUCKY STRIKE KW - MID ATLANTIC RIDGE SN - 0025-3154 TI - Reproductive biology, sexual dimorphism, and population structure of the deep sea hydrothermal vent scale-worm, Branchipolynoe seepensis (Polychaeta: Polynoidae) SP - 55 AV - none EP - 68 ER - TY - JOUR ID - soton48236 UR - https://eprints.soton.ac.uk/48236/ IS - 7 A1 - Jones, D.O.B. A1 - Bett, B.J. A1 - Tyler, P.A. Y1 - 2007/// N2 - The megabenthic ecology of the cold water (<0 °C) area of the Faroe?Shetland Channel was investigated using an off-bottom towed camera platform WASP (wide angle seabed photography). A series of 10 photographic transects, approximately evenly spaced along the channel axis, were studied. Photographic transects allowed quantitative benthic diversity data to be obtained from this understudied yet commercially important area for oil and gas exploration. The sedimentary characteristics of the seabed changed dramatically from a region of ice-rafted boulders and gravel in the southwest to fine sediments more typical of the deep sea to the northeast. Despite the relatively low species richness of the megabenthos, variation in faunal composition with depth was apparent. Two distinct ?communities? were identified, one in the south of the channel and the other in the north. Epibenthic megafaunal communities in the south were dominated by suspension and filter feeders and in the north by deposit feeders. Diversity and standing stock of megabenthos decreased to the northeast of the channel. Lebensspuren number and areal cover increased northwards in the Channel. The increase in bioturbation and deposit feeder abundance was concurrent with an increase in fine sediment quantity. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 54 KW - Megafauna KW - Abundance KW - Species diversity KW - Benthos KW - Photography KW - Towed camera platform KW - UK KW - Atlantic KW - Faroe?Shetland Channel KW - 60?64°N KW - 0?6°W SN - 0967-0637 TI - Megabenthic ecology of the deep Faroe?Shetland channel: a photographic study SP - 1111 AV - none EP - 1128 ER - TY - JOUR ID - soton360975 UR - https://eprints.soton.ac.uk/360975/ A1 - Jones, Daniel O.B. A1 - Alt, Claudia H.S. A1 - Priede, Imants G. A1 - Reid, William D.K. A1 - Wigham, Benjamin D. A1 - Billett, David S.M. A1 - Gebruk, Andrey V. A1 - Rogacheva, Antonina A1 - Gooday, Andrew J. Y1 - 2013/12/15/ N2 - The ecology, distribution and mode of life of three species of surface-dwelling enteropneusts is described, based on ROV observations and samples on the flanks of the Northern Mid-Atlantic Ridge (MAR) at comparative stations north and south of the Sub-Polar Front. Tergivelum cinnabarinum was most abundant in the north (mean=4.56 ind. 1000 m?2±3.50 s.d.) and occurred at low densities in the south (mean=1.19±1.68 s.d.). Yoda purpurata was dominant in the south (mean=17.00 ind. 1000 m?2±12.32 s.d.) but only one individual was found in the north. The within-station distribution of all enteropneust species encountered was generally random. T. cinnabarinum was larger (mean total length 142 mm) than Y. purpurata (mean total length 70 mm). Size distributions suggested smaller individuals of both species on the western side of the MAR. Size and density of enteropneusts were generally higher in areas with higher carbon flux to the seafloor. A single individual of Allapasus isidis was observed drifting and settling to the seafloor at the SW site. Traces on the seafloor made by T. cinnabarinum covered a much higher percentage of the total seabed area surveyed (mean=0.323%±0.155 s.d.) than those of Y. purpurata (mean=0.034%±0.037 s.d.). Stable isotope values for T. cinnabarinum suggested that it was a typical surficial deposit feeder. Enteropneusts appear to be abundant and an important bioturbator on the sedimented seafloor of the MAR at around 2500 m depth. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 98 KW - Acorn worms KW - Hemichordates KW - Tergivelum cinnabarinum KW - Yoda purpurata KW - Allapasus isidis KW - Benthic KW - Remotely operated vehicle KW - Mid-Atlantic Ridge KW - Photograph SN - 0967-0645 TI - Deep-sea surface-dwelling enteropneusts from the Mid-Atlantic Ridge: Their ecology, distribution and mode of life SP - 374 AV - none EP - 387 ER - TY - JOUR ID - soton362055 UR - https://eprints.soton.ac.uk/362055/ A1 - Jones, S.M. A1 - Murton, B.J. A1 - Fitton, J.G. A1 - White, N.J. A1 - Maclennan, J. A1 - Walters, R.L. Y1 - 2014/01/15/ N2 - The North Atlantic V-Shaped Ridges (VSRs) provide a spatially extensive and clear record of unsteady mantle convective circulation over >40 My>40 My. VSRs are diachronous ridges of thick crust formed with a periodicity of ?5 My?5 My along the Mid Atlantic Ridge, south of Iceland. We present data from a set of dredged basalt samples that shows chemical variation associated with two complete VSR crustal thickness cycles where they intersect the Mid Atlantic Ridge. The new dataset also records chemical variation associated with a VSR crustal thickness cycle along a plate spreading flow-line. Inverse correlations between crustal thickness and both incompatible trace element concentrations and incompatible element ratios such as Nb/Y and La/Sm are observed. Geochemical and crustal thickness observations can be matched using a time-dependent mid-ocean ridge melting model with a basal boundary condition of sinusoidally varying potential temperature. Our observations and models suggest that VSRs are generated when hot patches are carried up the plume stem beneath SE Iceland and spread radially outward within the asthenosphere. These patches are then drawn upward into the melting region when passing beneath the Mid Atlantic Ridge. The geometry of the VSRs and the size of the dynamically supported swell suggest that the Iceland Plume is the strongest plume in the Earth at present, with a volume flux of View the MathML source49±14 km3yr?1. JF - Earth and Planetary Science Letters VL - 386 KW - plume?ridge interaction KW - plume pulsing KW - plume flux KW - Iceland KW - Reykjanes Ridge KW - North Atlantic SN - 0012-821X TI - A joint geochemical?geophysical record of time-dependent mantle convection south of Iceland SP - 86 AV - none EP - 97 ER - TY - GEN ID - soton417539 UR - https://eprints.soton.ac.uk/417539/ A1 - Josey, Simon A. A1 - Hirschi, Joel J.M. A1 - Sinha, Bablu A1 - Duchez, Aurélie A1 - Grist, Jeremy P. A1 - Marsh, Robert Y1 - 2018/01/03/ N2 -

Cold ocean temperature anomalies have been observed in the mid- to high-latitude North Atlantic on interannual to centennial timescales. Most notably, a large region of persistently low surface temperatures accompanied by a sharp reduction in ocean heat content was evident in the subpolar gyre from the winter of 2013-2014 to 2016, and the presence of this feature at a time of pervasive warming elsewhere has stimulated considerable debate. Here, we review the role of air-sea interaction and ocean processes in generating this cold anomaly and place it in a longer-term context. We also discuss the potential impacts of surface temperature anomalies for the atmosphere, including the North Atlantic Oscillation and European heat waves; contrast the behavior of the Atlantic with the extreme warm surface event that occurred in the North Pacific over a similar timescale; and consider the possibility that these events represent a response to a change in atmospheric planetary wave forcing.

KW - air-sea heat flux KW - European impacts KW - large-scale ocean circulation KW - North Atlantic cold anomaly KW - North Pacific warm anomaly KW - sea surface temperature SN - 1941-1405 TI - The recent Atlantic cold anomaly: Causes, consequences, and related phenomena SP - 475 AV - none EP - 501 ER - TY - JOUR N1 - Funding Information: PJ, PL, SC, JR, SJK publish with the permission of the Executive Director, British Geological Survey (UKRI). This research was supported by Natural Environmental Research Council ( NERC ) grants NE/M011186/1 (awarded to B. Murton) and NE/M011151/1 (awarded to P. Lusty), which fund the MarineE-Tech project. A.M. acknowledges the generous support of the Warwickshire Geological Conservation Group (WGCG) as a recipient of the Holloway Award in 2017. The authors are grateful to the editor and anonymous reviewers for their helpful and constructive comments on the improvement of this manuscript. We thank Cheryl Haidon for her efforts and help in the processing of XRCT data at the University of Leicester. The authors gratefully thank the team involved in the RRS James Cook JC142 expedition to Tropic Seamount in 2016. Publisher Copyright: © 2020 British Geological Survey, a component body of UKRI 'BGS © UKRI 2020' ID - soton438059 UR - https://eprints.soton.ac.uk/438059/ A1 - Josso, Pierre A1 - Rushton, Jeremy A1 - Lusty, Paul A1 - Matthews, Adam A1 - Chenery, Simon A1 - Holwell, David A1 - Kemp, Simon J. A1 - Murton, Bramley Y1 - 2020/04/01/ N2 - Oceanic hydrogenetic ferromanganese (Fe-Mn) crusts precipitate directly from ambient seawater over millions of years. Their very slow growth rates and physio-chemical properties mean that they adsorb numerous elements from seawater. As such, they provide condensed records of seawater evolution through time that can be used for paleoceanographic reconstruction. Here, we present the results of a high-resolution, stratigraphic, textural and geochemical investigation of a core sample, obtained from a Fe-Mn crust pavement, located on the summit of Tropic Seamount in the tropical north-east Atlantic Ocean. A number of observations and interpretations are proposed, within the context of a well-constrained age model, spanning the last 75 ± 2 Myr. This core has textural stratigraphic coherence with Pacific Fe-Mn crusts formed since the Late Cretaceous, highlighting that global oceanic and climatic phenomena exert first-order controls on Fe-Mn crust development. All major hiatuses observed in the Fe-Mn crusts are contemporaneous with erosion events occurring throughout the Atlantic Ocean. High-resolution geochemical data indicate that there is variability in the composition of Fe-Mn crusts at the cm to ?m scale. The dominant factors controlling this include major oceanographic events, mineral textures and micro-topography. JF - Marine Geology VL - 422 KW - Atlantic KW - FeMn crust KW - Geochemistry KW - Paleoceanography KW - Phosphatisation SN - 0025-3227 TI - Late Cretaceous and Cenozoic paleoceanography from north-east Atlantic ferromanganese crust microstratigraphy AV - public EP - 17 ER - TY - JOUR ID - soton7836 UR - https://eprints.soton.ac.uk/7836/ IS - 2 A1 - Joyce, T.M. A1 - Bryden, H.L. A1 - Parrilla, G. Y1 - 2001/// JF - CLIVAR Exchanges VL - 6 KW - NORTH ATLANTIC OCEAN KW - DECADAL VARIABILITY KW - THERMOCLINE KW - CLIVAR KW - GYRES TI - Comments on an article entitled 'Are we seeing human-induced warming of the deep layers in the north subtropical Atlantic?' by A.B. Polensky SP - 27 AV - none EP - 28 ER - TY - JOUR ID - soton354485 UR - https://eprints.soton.ac.uk/354485/ IS - 20 A1 - Jullion, Loïc A1 - Naveira Garabato, Alberto C. A1 - Meredith, Michael P. A1 - Holland, Paul R. A1 - Courtois, Peggy A1 - King, Brian A. Y1 - 2013/10// N2 - Recent decadal changes in Southern Hemisphere climate have driven strong responses from the cryosphere. Concurrently, there has been a marked freshening of the shelf and bottom waters across a wide sector of the Southern Ocean, hypothesised to be caused by accelerated glacial melt in response to a greater flux of warm waters from the Antarctic Circumpolar Current onto the shelves of West Antarctica. However, the circumpolar pattern of changes has been incomplete: no decadal freshening in the deep layers of the Atlantic sector had been observed. In this study, we document a significant freshening of the Antarctic Bottom Water exported from the Weddell Sea, which is the source for the abyssal layer of the Atlantic overturning circulation, and we trace its possible origin to atmospheric-forced changes in the ice shelves and sea ice on the eastern flank of the Antarctic Peninsula that include an anthropogenic component. These findings suggest that the expansive and relatively cool Weddell gyre does not insulate the bottom water formation regions in the Atlantic sector from the ongoing changes in climatic forcing over the Antarctic region. JF - Journal of Climate VL - 26 KW - South Atlantic Ocean KW - Southern Ocean KW - Ocean circulation KW - Abyssal circulation KW - Bottom currents/bottom water KW - Trends SN - 0894-8755 TI - Decadal freshening of the Antarctic Bottom Water exported from the Weddell Sea SP - 8111 AV - none EP - 8125 ER - TY - JOUR ID - soton50299 UR - http://www.gsajournals.org/perlserv/?request=get-document&doi=10.1130%2FG23917A.1#i0091-7613-35-11-1051-Ferdelman1 IS - 11 A1 - Kano, A. A1 - Ferdelman, T.G. A1 - Williams, T. A1 - Henriet, J-P. A1 - Ishikawa, T. A1 - Kawagoe, N. A1 - Takashima, C. A1 - Kakizaki, Y. A1 - Abe, K. A1 - Sakai, K. A1 - Browning, E.L. A1 - Li, X. A1 - Huvenne, V. Y1 - 2007/11// N2 - Sr isotope stratigraphy provides a new age model for the first complete section drilled through a deep-water coral mound. The 155-m-long section from Challenger Mound in the Porcupine Sea-bight, southwest of Ireland, is on Miocene siliciclastics and consists entirely of sediments bearing well-preserved cold-water coral Lophelia pertusa. The 87Sr/86Sr values of 28 coral specimens from the mound show an upward-increasing trend, correspond to ages from 2.6 to 0.5 Ma, and identify a significant hiatus from ca. 1.7 to 1.0 Ma at 23.6 m below seafloor. The age of the basal mound sediments coincides with the intensification of Northern Hemisphere glaciations that set up the modern stratification of the northeast Atlantic and enabled coral growth. Mound growth persisted throughout glacial-interglacial fluctuations, reached a maximum rate (24 cm/k.y.) ca. 2.0 Ma, and ceased at 1.7 Ma. Unlike other buried mounds in Porcupine Seabight, Challenger Mound was only partly covered during its growth interruption, and growth restarted ca. 1.0 Ma.
JF - Geology VL - 35 KW - deep-water coral mound KW - northeast Atlantic KW - Porcupine Sea-bight KW - 87Sr/86Sr KW - Pliocene-Pleistocene KW - Integrated Ocean Drilling Program SN - 0091-7613 TI - Age constraints on the origin and growth history of a deep-water coral mound in the northeast Atlantic drilled during Integrated Ocean Drilling Program Expedition 307 SP - 1051 AV - none EP - 1054 ER - TY - JOUR ID - soton63934 UR - https://eprints.soton.ac.uk/63934/ IS - 12 A1 - Kanzow, T. A1 - Send, U. A1 - McCartney, M. Y1 - 2008/12// N2 - A 5-year-long time series of meridional transport below 1180 dbar?zonally integrated across a section spanning, the western basin of the tropical North Atlantic?is analyzed. It has been inferred from (i) zonally integrated meridional geostrophic transports derived from density and bottom pressure measurements at the end points of a 1000 km wide section bounded by the base of the western continental rise and the Mid-Atlantic Ridge and (ii) mooring-based direct current meter measurements over the steep Lesser Antilles continental rise. The southward time mean transport of North Atlantic Deep Water (NADW) transport is 15.9 Sv. The vertical shear of the geostrophic transport profiles in the western and eastern part of the section each show two layers of maximum southward transport within the NADW. The transport time series reveals changes of 7.7 Sv rms at periods of 1 month and longer, at times showing changes of up to 40 Sv within a month's time. The baroclinic (internal) contribution of the geostrophic flow (relative to 4950 dbar), yields fluctuations of 6.6 Sv rms. Adding transports over the steep continental rise reduces the overall transport variability to 5.2 Sv rms. As a result of this reduction in shorter-period variability, the lower-frequency variability becomes more pronounced, part of which is expected to be linked to the meridional overturning circulation (MOC). The transport variability is consistent with baroclinic Rossby waves (at periods between 3 and 9 months), dominating in the eastern and central part of the section, and with changes in deep western boundary current (DWBC) strength, DWBC re-circulation patterns and eddies that become important in the western part of the section. The reference-level (external) geostrophic transport variability displays long-wavelength (>2000 km) fluctuations of 7.5 Sv rms on periods less than 2 weeks that are consistent with barotropic Rossby waves.
Numerical model simulations imply that the observed zonally integrated deep transport changes in the western basin have moderate skill in sensing changes in the MOC and in meridional heat transport, and that a now implemented extension of the array's integration scale into the eastern basin of the Atlantic would substantially improve the performance of the array as an MOC observing system.
JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 55 KW - Ocean transport KW - North Atlantic Deep Water KW - Density KW - Bottom pressure KW - Time series KW - Monitoring KW - Meridional overturning circulation KW - Geostrophy KW - Mooring array KW - Tropical Atlantic KW - Rossby waves KW - Deep western boundary current KW - Re-circulation SN - 0967-0637 TI - On the variability of the deep meridional transports in the tropical North Atlantic SP - 1601 AV - none EP - 1623 ER - TY - RPRT ID - soton66003 UR - https://eprints.soton.ac.uk/66003/ A1 - Kanzow, T.O. Y1 - 2009/04// N2 - This report describes the mooring operations conducted on the RV Seward Johnson cruise SJ08-03 Leg 2 between 22nd April and 30th April 2008.

These mooring operations were completed as part of the United Kingdom Natural Environment Research Council (NERC) RAPID and RAPID-WATCH programmes to monitor the Atlantic Meridional Overturning Circulation at 26.5°N. The primary purpose of this cruise was to service the Western Boundary section of the 26.5°N mooring array first deployed in 2004 during RRS Discovery cruises D277 and D278 (SOC cruise report number 53).

Cruise SJ08-03 leg 2 sailed from Freeport, Grand Bahama to Ft. Pierce, Florida and serviced the moorings deployed on RB0701 (along with 2 landers deployed on RB0602). This cruise is the fourth annual refurbishment of the Western Boundary section of an array of moorings deployed across the Atlantic in order to set up a pre-operational prototype system to continuously observe the Atlantic Meridional Overturning Circulation (MOC). This array will be further refined and refurbished during subsequent years.

The instrumentation deployed on the array consists of a variety of current meters, bottom pressure recorders, CTD loggers and Inverted Echo Sounders, which, combined with time series measurements of the Florida Channel Current and wind stress estimates, will be used to determine the strength and structure of the MOC at 26.5°N.
(http://www.noc.soton.ac.uk/rapidmoc) PB - National Oceanography Centre T3 - 37 KW - RAPID-MOC KW - thermohaline circulation KW - Atlantic Ocean KW - Western Boundary Current KW - Seward Johnson KW - cruise 2008 KW - cruise SJ08-03 KW - moorings KW - SeaBird KW - MicroCATS KW - bottom pressure recorders KW - CTD ED - Collins, J.L. M1 - project_report TI - RV Seward Johnson Cruise SJ08-03 Leg 2, 22-30 Apr 2008: RAPID-MOC Spring 2008 Western Boundary moorings refurbishment cruises AV - public EP - 73 ER - TY - RPRT ID - soton59066 UR - https://eprints.soton.ac.uk/59066/ A1 - Kanzow, T.O. A1 - Cunningham, S.A. Y1 - 2008/08// N2 - This report describes the Autumn 2006 Eastern Boundary moorings refurbishment cruises for the RAPID-MOC programme Monitoring the Atlantic Meridional Overturning Circulation at 26.5°N. Two cruises are reported here: FS Poseidon cruise P343 (4 OCT ? 17 OCT) and FS Poseidon cruise P345 (28 NOV ? 7 DEC). Both cruises sailed to and from Las Palmas, Gran Canaria.

Six moorings were recovered during P343 and 13 deployed. Parafil failures on EB1 and EB2 (5000m long moorings located near 24°N, 24°W) during deployment necessitated immediate recovery. This led to an emergency cruise P345 to recover EB2 and to redeploy EB1 and EB2. P343 was also notable for the first deployment of seven mini-moorings consisting of a single microcat between 500m and 50m depth. PB - National Oceanography Centre T3 - 28 KW - RAPID-MOC KW - thermohaline circulation KW - Atlantic Ocean KW - Eastern Boundary KW - Poseidon KW - cruise 2006 KW - cruise P343 KW - cruise P345 KW - moorings KW - SeaBird KW - microcats KW - bottom pressure recorders KW - CTD ED - Collins, J. M1 - project_report TI - FS Poseidon Cruises P343, 04 Oct-17 Oct 2006 and P345, 28 Nov-07 Dec 2006. RAPID-MOC Autumn 2006 Eastern Boundary moorings refurbishment cruises AV - public EP - 108 ER - TY - JOUR ID - soton366918 UR - https://eprints.soton.ac.uk/366918/ IS - 4 A1 - Kazanidis, Georgios A1 - Tyler, Paul A. A1 - Billett, David S.M. Y1 - 2014/06// N2 - Long-term studies in the abyssal north-east Atlantic (1989?2005) have revealed large-scale changes in the benthic ecosystem and especially in some megafaunal invertebrate taxa over the period 1996?2002, termed the ?Amperima Event?. Holothurians dominated the megafaunal samples. Temporal patterns in the abundance of holothurians showed a wide spectrum of responses, possibly related to the feeding and reproductive characteristics of the various species. One of the holothurians, the synallactid Paroriza prouhoi, is a simultaneous hermaphrodite, providing a distinct comparison with dioecious reproductive patterns more typical of deep-sea holothurian species. The reproductive biology and abundance/biomass patterns of P. prouhoi were investigated over the period 1989?2005. Paroriza prouhoi produces oocytes with a maximum diameter of ~370 µm. It has asynchronous patterns of gametogenesis both at the individual and population levels. Mean oocyte diameter and the ratio between previtellogenic and vitellogenic oocytes showed no significant differences between the periods prior to and after the Amperima Event. There were no significant differences in abundance or biomass over the time series. We conclude that the energy investment into gamete production by this hermaphrodite did not change over the 16 years examined. It is hypothesized that the feeding characteristics of P. prouhoi lead to a slow, steady and consistent production of gametes despite large-scale changes in organic matter supply to the seabed evident at the time series locality. JF - Journal of the Marine Biological Association of the United Kingdom VL - 94 KW - deep sea KW - holothurians KW - reproduction KW - hermaphrodite KW - temporal change KW - Porcupine Abyssal Plain KW - north-east Atlantic SN - 0025-3154 TI - On the reproduction of the simultaneous hermaphrodite Paroriza prouhoi (Holothuroidea: Synallactidae) in the Porcupine Abyssal Plain, north-east Atlantic SP - 847 AV - none EP - 856 ER - TY - JOUR ID - soton8812 UR - https://eprints.soton.ac.uk/8812/ IS - 3/4 A1 - Kempton, P.D. A1 - Fitton, J.G. A1 - Saunders, A.D. A1 - Nowell, G.M. A1 - Taylor, R.N. A1 - Hardarson, B.S. A1 - Pearson, G. Y1 - 2000/// N2 - New Sr?Nd?Pb?Hf data require the existence of at least four mantle components in the genesis of basalts from the North Atlantic Igneous Province (NAIP): (1) one (or more likely a small range of) enriched component(s) within the Iceland plume, (2) a depleted component within the Iceland plume (distinct from the shallow N-MORB source), (3) a depleted sheath surrounding the plume and (4) shallow N-MORB source mantle. These components have been available since the major phase of igneous activity associated with plume head impact during Paleogene times. In Hf?Nd isotope space, samples from Iceland, DSDP Leg 49 (Sites 407, 408 and 409), ODP Legs 152 and 163 (southeast Greenland margin), the Reykjanes Ridge, Kolbeinsey Ridge and DSDP Leg 38 (Site 348) define fields that are oblique to the main ocean island basalt array and extend toward a component with higher 176Hf/177Hf than the N-MORB source available prior to arrival of the plume, as indicated by the compositions of Cretaceous basalts from Goban Spur (~95 Ma). Aside from Goban Spur, only basalts from Hatton Bank on the oceanward side of the Rockall Plateau (DSDP Leg 81) lie consistently within the field of N-MORB, which indicates that the compositional influence of the plume did not reach this far south and east ~55 Ma ago. Thus, Hf?Nd isotope systematics are consistent with previous studies which indicate that shallow MORB-source mantle does not represent the depleted component within the Iceland plume [Thirlwall, J. Geol. Soc. London 152 (1995) 991?996; Hards et al., J. Geol. Soc. London 152 (1995) 1003?1009; Fitton et al., Earth Planet. Sci. Lett. 153 (1997) 197?208]. They also indicate that the depleted component is a long-lived and intrinsic feature of the Iceland plume, generated during an ancient melting event in which a mineral (such as garnet) with a high Lu/Hf was a residual phase. Collectively, these data suggest a model for the Iceland plume in which a heterogeneous core, derived from the lower mantle, consists of ?enriched? streaks or blobs dispersed in a more depleted matrix. A distinguishing feature of both the enriched and depleted components is high Nb/Y for a given Zr/Y (i.e. positive ?Nb), but the enriched component has higher Sr and Pb isotope ratios, combined with lower ?Nd and ?Hf. This heterogeneous core is surrounded by a sheath of depleted material, similar to the depleted component of the Iceland plume in its ?Nd and ?Hf, but with lower 87Sr/86Sr, 208Pb/204Pb and negative ?Nb; this material was probably entrained from near the 670 km discontinuity when the plume stalled at the boundary between the upper and lower mantle. The plume sheath displaced more normal MORB asthenosphere (distinguished by its lower Hf for a given Nd or Zr/Nb ratio), which existed in the North Atlantic prior to plume impact. Preliminary data on MORBs from near the Azores plume suggest that much of the North Atlantic may be ?polluted? not only by enriched plume material but also by depleted material similar to the Iceland plume sheath. If this hypothesis is correct, it may provide a general explanation for some of the compositional diversity and variations in inferred depth of melting [Klein and Langmuir, J. Geophys. Res. 92 (1987) 8089?8115] along the MAR in the North Atlantic. JF - Earth and Planetary Science Letters VL - 177 KW - NORTH ATLANTIC OCEAN KW - NORTH ATLANTIC IGNEOUS PROVINCE KW - NAIP KW - ICELAND KW - MANTLE PLUMES KW - MORB KW - STRONTIUM KW - NEODYMIUM KW - LEAD KW - HAFNIUM KW - RIFTING KW - GEOCHEMISTRY KW - ISOTOPES KW - BASALTS SN - 0012-821X TI - The Iceland plume in space and time: a Sr-Nd-Pb-Hf study of the North Atlantic rifted margin SP - 255 AV - none EP - 271 ER - TY - JOUR ID - soton55833 UR - http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0485%281995%29025%3C1530%3AACOSAL%3E2.0.CO%3B2 IS - 6 A1 - Kent, E.C. A1 - Taylor, P.K. Y1 - 1995/06// N2 - Previously published estimates of the surface turbulent fluxes over the North Atlantic Ocean have been compared by applying the calculation methods used by each author to a common dataset of ship observations. The major differences between the various flux estimations were due to whether or not the data were corrected for observation height, the method of calculating averaged fluxes and the choice of transfer coefficient.

By correcting the ship observations obtained from the Voluntary observing ship Special Observing Programme?North Atlantic for known observational biases an estimate of the correct values for the fluxes has been made. The previous studies were found to have overestimated the North Atlantic sea to air heat transfer by up to 30%. All of the schemes overestimated the annual cycle, giving fluxes approximately equal to the best estimate values in the summer but much higher fluxes in the winter. The use of transfer coefficient values much larger than the values determined by air-sea interaction experiments could not be justified by either the effects of measurement errors or by fair weather bias. The lower turbulent flux values are compatible with a balanced North Atlantic heat budget, given the uncertainty in the other flux terms. JF - Journal of Physical Oceanography VL - 25 KW - surface flux KW - north atlantic KW - climatology KW - comparison KW - parameterisation SN - 0022-3670 TI - A comparison of sensible and latent heat flux estimates for the North Atlantic ocean SP - 1530 AV - none EP - 1549 ER - TY - JOUR ID - soton2059 UR - https://eprints.soton.ac.uk/2059/ IS - 1-4 A1 - Kenyon, N.H. A1 - Akhmetzhanov, A.M. A1 - Wheeler, A.J. A1 - Van Weering, T.C.E. A1 - De Haas, H. A1 - Ivanov, M.K. Y1 - 2003/// N2 - Seismic profiles, sidescan sonar data, bottom photography and sampling proved for the first time that there are giant carbonate mounds (bioherms) in the Rockall Trough. The Pelagia Mounds, on the northern Porcupine Bank, are relatively isolated whereas most of the Logachev Mounds, on the southeast Rockall Bank, form a field of closely spaced, contiguous mounds. They are all found on the upper slope at depths between about 500 and 1200 m and as a result of this study about 500 have been mapped. They have a variety of shapes and the larger ones are very steep-sided, up to 350 m high and 2 km wide at the base. Sediment samples show that the mounds consist of pale coloured muds, mainly aragonite, usually with live and/or dead cold-water corals at the seafloor and with buried dead corals. Coral thickets appear to be detected as a brush-like signature on high resolution profiles and as a speckled pattern on high resolution sidescan sonar records. Shelly sands are found on the seabed between the mounds. Currents in the mound areas are strong enough to transport sands along slope as medium-sized sand waves and to prevent pelagic deposition, thus providing surfaces for initial coral settlement by the winnowing of fines to leave glacial dropstones and exposed rocks. These observations show that the poleward-directed upper slope current of the eastern North Atlantic extends further south than hitherto known and that there is a southwesterly directed current on Rockall Bank. There are waves on the Logachev Mounds, with a wavelength of about 20?30 m, that are thought to be moulded in carbonate muds by across-slope directed internal tidal currents and/or cascading currents. Mounds develop above erosional surfaces seen on seismic data. The huge amount of carbonate mud seems to be produced by the rapid growth and breakdown of cold-water corals living in a very favourable environment. Intermediate nepheloid layers formed upstream by the strong currents may provide the food source for the deep water suspension feeders. Conditions for giant mound growth require an ideal balance between current speed and sedimentation rate, among other factors. No evidence for the suggested link to methane seepage has been found so far. JF - Marine Geology VL - 195 KW - Northeast Atlantic KW - mud mounds KW - deep water corals KW - bottom currents KW - sediment transport KW - internal waves SN - 0025-3227 TI - Giant carbonate mud mounds in the southern Rockall Trough SP - 5 AV - none EP - 30 ER - TY - RPRT ID - soton344625 UR - https://eprints.soton.ac.uk/344625/ A1 - King, B.A. Y1 - 2012/10// N2 - A Hydrographic section was occupied at a nominal latitude of 24.5°N in the Atlantic Ocean during January - February 2010 on Cruise 346 of RRS Discovery. The primary objective of this cruise was to measure ocean physical, chemical and biological parameters in order to establish regional budgets of heat, freshwater and carbon, and to infer decadal variability.

A total of 135 CTD/LADCP stations were sampled, with two additional bottle blank stations. In addition to temperature, salinity and oxygen profiles from the sensors on the CTD package, water samples from a 24 x 20 litre rosette were analysed for salinity, dissolved oxygen and inorganic nutrients at each station. Water samples were collected from strategically selected stations and analysed onboard ship for SF6, CFCs, DIC, alkalinity, and filtering. In addition, samples were collected from the ships?underway system to calibrate and compliment the data continually collected by the TSG (thermosalinograph). Full depth velocity measurements were made at every station by LADCP (Lowered Acoustic Doppler Current Profiler) mounted on the frame of the rosette. Throughout the cruise, velocity data in the upper few hundred metres of the water column were collected by the ship?s VMADCP (Vessel Mounted Acoustic Doppler Current Profiler) transducers (75Hz and 150Hz) mounted on the hull. Meteorological variables were monitored using the onboard surface water and meteorological sampling system (SURFMET). Bathymetric data was collected using the EA600 echo sounder, which is attached to the hull. However, whilst steaming it was found that switching over to the fish instrument produced a cleaner dataset.

This report describes the methods used to acquire and process the data on board the ship during cruise D346. PB - National Oceanography Centre T3 - 16 KW - adcp KW - atlantic ocean KW - carbon KW - cfc KW - circulation KW - cruise D346 2010 KW - ctd KW - Discovery KW - lowered adcp KW - meridional overturning circulation KW - meteorology KW - moc KW - nutrients KW - oxygen KW - shipboard ED - Hamersley, D.R.C. M1 - project_report TI - RRS Discovery Cruise 346, 05 Jan - 19 Feb 2010. The 2010 transatlantic hydrography section at 24.5°N AV - public EP - 177 ER - TY - RPRT ID - soton159061 UR - https://eprints.soton.ac.uk/159061/ A1 - King, B.A. A1 - et al, Y1 - 2010/// N2 - Hydrographic sections were occupied in the South Atlantic Ocean and during March - April 2009 aboard the RRS James Cook (JC032). Three of these sections intersected the Brazil current at three separate latitudes during the steam northwards from Montevideo. The main trans-Atlantic section was occupied at 24°S. The primary objective of this cruise was to measure ocean physical, chemical and biological parameters in order to establish regional budgets of heat freshwater and carbon. The main section completed an overall aim, devised under the Oceans 2025 project, to create a box around the South Atlantic and Southern Ocean region to expose the regional circulation scheme and basin-scale budgets of physical and biogeochemical properties by performing a box-inverse analysis of the new observations.

A total of 118 CTD/LADCP stations were sampled across the South Atlantic. In addition to temperature, salinity and oxygen profiles from the sensors on the CTD package, water samples from a 24-bottle rosette were analysed for salinity, dissolved oxygen and inorganic nutrients at each station. Water samples were collected from strategically selected stations and analysed onboard ship for SF6, CFC?s, pCO2, TIC, alkalinity, and nutrient biogeochemistry. In addition, samples were collected from the ship?s underway system to calibrate and compliment the data continually collected by the TSG (thermosalinograph). Full depth velocity measurements were made at every station by an LADCP (Lowered Acoustic Doppler Current Profiler) mounted on the frame of the rosette. Throughout the cruise, velocity data in the upper few hundred metres of the water column were collected by the ship?s VMADCP (vessel mounted acoustic Doppler current profiler) transducers (75Hz and 150Hz) mounted on the hull. Meteorological variables were monitored using the onboard surface water and meteorological sampling system (SURFMET). Bathymetric data was collected using the EA600 echo sounder and EM120 swath system, which is attached to the hull.

This report describes the methods used to acquire and process the data aboard the ship during cruise JC032. PB - National Oceanography Centre T3 - 48 KW - ADCP KW - Atlantic Ocean KW - biogeochemical budgets KW - Brazil Current KW - carbon budgets KW - Carbon Tetrachloride KW - Carbon KW - CFC KW - James Cook KW - climatic changes KW - cruise JC032 2009 KW - CTD KW - hydrographic section KW - LoweredADCP KW - Meridional Overturning Circulation KW - nutrients KW - oxygen KW - phytoplankton KW - potential temperature KW - salinity KW - Sulphur Hexafluoride KW - temperature KW - Vessel Mounted ADCP ED - Hamersley, D.R.C. M1 - project_report TI - RSS James Cook Cruise JC032, 07 Mar ? 21 Apr 2009. Hydrographic sections across the Brazil Current and at 24°S in the Atlantic. AV - public EP - 173 ER - TY - RPRT ID - soton346861 UR - https://eprints.soton.ac.uk/346861/ A1 - King, B.A. A1 - et al, Y1 - 2012/12// N2 - RRS Discovery Cruise 368 was a repeat occupation of part of the Atlantic hydrographic section designated by the World Ocean Circulation Experiment (WOCE) as A16N. A total of 29 CTDO (conductivity-temperature-depth-oxygen) stations were occupied. This included one test station, 27 stations between 49N and 23N on the WOCE A16N ?20W? line, and one final station near the ESTOC site close to Tenerife. Continuous profile measurements were CTDO and Lowered Acoustic Doppler Current Profiler (LADCP). Discrete bottle measurements from a 24-place rosette included salinity and dissolved oxygen analysed on board, and dissolved inorganic nutrients, Dissolved Inorganic Carbon and Total Alkalinity for analysis ashore. Underway measurements included Vessel-Mounted ADCP, surface ocean measurements and surface meteorology. The cruise was a UK contribution to the GO-SHIP sustained hydrography program. It was a partial repeat of the line designated in WOCE as A16N, which was previously occupied as a comprehensive cruise in 2003. In addition, a microbial program was carried out as an opportunistic activity by scientists who would remain on board for the following cruise.

This report describes the methods used to acquire and process the data on board the ship during RRS Discovery Cruise 368.
PB - National Oceanography Centre T3 - 20 KW - ADCP KW - Atlantic Ocean KW - carbon KW - circulation KW - cruise D368 2011 KW - CTD KW - Discovery KW - Lowered ADCP KW - nutrients KW - oxygen KW - shipboard ADCP M1 - project_report TI - RRS Discovery Cruise 368, 15 Jul - 04 Aug 2011. Hydrographic measurements on WOCE line A16N AV - public EP - 64 ER - TY - JOUR ID - soton448953 UR - https://eprints.soton.ac.uk/448953/ A1 - Kirby, Nicola A1 - Bailey, Ian A1 - Lang, David C. A1 - Brombacher, Anieke A1 - Chalk, Thomas B. A1 - Parker, Rebecca L. A1 - Crocker, Anya J. A1 - Taylor, Victoria E. A1 - Milton, James A. A1 - Foster, Gavin L. A1 - Raymo, Maureen E. A1 - Kroon, Dick A1 - Bell, David B. A1 - Wilson, Paul A. Y1 - 2020/12/15/ N2 -

Marine Isotope Stage (MIS) M2, 3.3 Ma, is an isolated cold stage punctuating the benthic oxygen isotope (? 18O) stratigraphy of the warm Piacenzian interval of the late Pliocene Epoch. The prominent (?0.65?) ? 18O increase that defines MIS M2 has prompted debate over the extent to which it signals an early prelude to the rhythmic extensive glaciations of the northern hemisphere that characterise the Quaternary and raised questions about the forcing mechanisms responsible. Recent work suggests that CO 2 storage in the deep Atlantic Ocean played an important role in these events but detailed reconstructions of deep ocean chemical stratification are needed to test this idea and competing hypotheses. Here we present new records of the Nd isotope composition of fish debris and ? 13C and B/Ca ratios of benthic foraminifera from the northwest and southeast Atlantic Ocean. Our novel geochemical data show that, in contrast to major Quaternary glaciations such as MIS 2 (?21 ka) and MIS 100 (?2.52 Ma), the deep North Atlantic Ocean was weakly chemically stratified during MIS M2. We show that Southern Component Water incursion into the Atlantic Ocean was limited to the deep South Atlantic basin during MIS M2 and peaked well before (?10-15-kyr) the atmospheric CO 2 minimum. Our findings imply that the deep Atlantic Ocean was not the principle sink of CO 2 sequestered from the atmosphere during MIS M2, implicating a different CO 2 storage deep-water reservoir mechanism, presumably Southern Component Water incursion into the Pacific Ocean. Weak chemical stratification in the deep Atlantic Ocean during MIS M2 relative to MIS 100 and 2 suggests comparatively active Atlantic meridional overturning circulation. That suggestion is consistent with the warmth of the high latitude North Atlantic during MIS M2 ? surface water temperatures cooled during M2 but only close to Holocene values. Our findings may help to explain the paucity of evidence for extensive early glaciation of the northern hemisphere during M2 but leave open the possibility of ice sheet advance on Antarctica.

JF - Quaternary Science Reviews VL - 250 KW - AABW KW - AMOC KW - Atlantic circulation KW - Last glacial KW - MIS 100 KW - MIS M2 KW - NADW SN - 0277-3791 TI - On climate and abyssal circulation in the Atlantic Ocean during late Pliocene marine isotope stage M2, ?3.3 million years ago AV - public ER - TY - JOUR ID - soton7833 UR - https://eprints.soton.ac.uk/7833/ IS - 1/4 A1 - Kiriakoulakis, Konstadinos A1 - Stutt, Edward A1 - Rowland, Steven J. A1 - Vangriesheim, Annick A1 - Lampitt, Richard S. A1 - Wolff, George A. Y1 - 2001/// N2 - The organic matter of sinking particulate material collected in the Northeast Atlantic Ocean (ca. 49°N, 16°W) was investigated in order to determine temporal and depth-related variability in its composition. Three sediment traps were deployed at nominal depths of 1000 m (below the permanent thermocline), 3000 m (representing the deep-water fluxes) and at 4700 m, about 100 m above the seafloor (just above the benthic boundary layer). The samples span a 28-month sampling period from October 1995 until February 1998, each sample representing a period of between 7 and 28 days.
Total organic carbon and total nitrogen contents decrease with depth, as did the absolute concentrations of most biochemicals measured in this study, such as intact proteins and individual lipids. However, concentrations of proteins relative to total organic carbon and total nitrogen did not show any significant change with depth, implying that they are not being rapidly degraded and so may provide an important supply of nitrogen to the benthos. Fluxes of protein, TN and TOC are significantly correlated at all depths.
Lipid compositions vary temporally. During periods of high flux, particularly in the summer, the lipids are richer in ?labile components?, namely unsaturated fatty acids and low molecular weight alcohols. During periods of low flux other compounds, such as sterols, steroidal ketones and a trisnorhopan-21-one are more abundant. One sample, taken close to the seafloor, was highly enriched in lipids, sterols and fatty acids in particular; this may represent detritus derived from bottom-dwelling invertebrates. JF - Progress in Oceanography VL - 50 KW - northeast atlantic ocean KW - sampling KW - sinking particles KW - lipids KW - organic carbon KW - nitrogen SN - 0079-6611 TI - Controls on the organic chemical composition of settling particles in the northeast Atlantic Ocean SP - 65 AV - none EP - 87 ER - TY - JOUR ID - soton7828 UR - https://eprints.soton.ac.uk/7828/ IS - 1/2 A1 - Klingelhofer, F. A1 - Minshull, T.A. A1 - Blackman, D.K. A1 - Harben, P. A1 - Childers, V. Y1 - 2001/// JF - Earth and Planetary Science Letters VL - 190 KW - ASCENSION ISLANDS KW - OCEAN CRUST KW - SEISMOLOGY KW - VOLCANIC ISLANDS KW - VOLCANISM KW - ATLANTIC OCEAN KW - GEOLOGY SN - 0012-821X TI - Crustal structure of Ascension Island from wide-angle seismic data: implications for the formation of near-ridge volcanic islands SP - 41 AV - none EP - 56 ER - TY - JOUR ID - soton12725 UR - https://eprints.soton.ac.uk/12725/ IS - 8 A1 - Koeve, W. A1 - Pollehne, F. A1 - Oschlies, A. A1 - Zeitzschel, B. Y1 - 2002/// N2 - Observations during a spring phytoplankton bloom in the northeast Atlantic between March and May 1992 in the Biotrans region at 47°N, 20°W, are presented. During most of the observation period there was a positive heat flux into the ocean, winds were weak, and the mixed layer depth was shallow (<40 m). Phytoplankton growth conditions were favourable during this time. Phytoplankton biomass roughly doubled within the euphotic zone over the course of about 7 days during mid-April, and rapidly increased towards the end of the study until silicate was depleted. However, the stratification of the water column was transient, and the spring bloom development was repeatedly interrupted by gales. During two storms, in late March and late April, the mixed-layer depth increased to 250 and 175 m, respectively. After the storm events significant amounts of chlorophyll-a, particulate organic carbon and biogenic silica were found well below the euphotic zone. It is estimated that between 56% and 65% of the seasonal new production between winter and early May was exported from the euphotic zone by convective mixing, in particular, during the two storm events. Data from the NABE 47°N study during spring 1989 are re-evaluated. It is found that convective particle export was of importance during the early part of that bloom too, but negligible during the height of the bloom in May 1989. The overall impact of convective particle export during spring 1989 was equivalent to about 36% of new production. In view of these and previously published findings it is concluded that convective transport during spring is a significant process for the export of particulate matter from the euphotic zone in the temperate North Atlantic. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 49 KW - Carbon KW - Suspended particulate matter KW - Atmospheric forcing KW - Oceanic boundary layer KW - Algal blooms KW - Particulate flux KW - AN North Atlantic SN - 0967-0637 TI - Storm induced convective transport of suspended matter during a spring bloom in the northeast Atlantic Ocean SP - 1431 AV - none EP - 1444 ER - TY - GEN ID - soton485751 UR - https://eprints.soton.ac.uk/485751/ A1 - Kokuhennadige, Hashan Niroshana A1 - Whiteside, Jessica A1 - Connelly, Douglas A1 - Achterberg, Eric A1 - Humphreys, Matthew P. Y1 - 2023/12// N2 - These datasets contain stable carbon isotopic composition of dissolved inorganic carbon (δ13CDIC) and particulate organic carbon (δ13CPOC) for the Eastern Atlantic Ocean. These include three datasets: Dataset_BUS, Dataset_PAP and Dataset_NEA. Dataset_BUS contains stable carbon isotopic composition of dissolved inorganic carbon (δ13CDIC), DIC and nutrients in the coastal waters of the Benguela Upwelling System in the southeast Atlantic Ocean during the GEOTRACES cruise GA08 in the summer (November - December) of 2015. Dataset_PAP contains stable carbon isotopic composition of particulate organic carbon (δ13CPOC), dissolved inorganic carbon (δ13CDIC) and of the sedimentary organic carbon in the surface sediments, POC, DIC and chlorophyll a at the Porcupine Abyssal Plain (PAP) site in the northeast Atlantic Ocean during the DY130 cruise in the spring (March - April) of 2021. Dataset_NEA contains stable carbon isotopic composition of dissolved inorganic carbon (δ13CDIC) and particulate organic carbon (δ13CPOC), DIC, POC and phosphate in the subtropical gyre region of the northeast Atlantic Ocean during the SO279 cruise in the winter (December 2020 - January 2021) of 2020. PB - University of Southampton KW - Eastern Atlantic Ocean KW - Stable carbon isotopes KW - DIC KW - POC TI - Datasets in support of the thesis ‘Stable carbon isotopes from the Eastern Atlantic Ocean: anthropogenic and biological signals’ AV - public ER - TY - THES ID - soton485788 UR - https://eprints.soton.ac.uk/485788/ A1 - Kokuhennadige, Hashan Niroshana Y1 - 2023/// N2 - Stable isotope analyses of environmental samples provide information on the source of materials and the processes responsible for their formation and conversion, and consequently offer information on processes and dynamics in ecosystems. The stable carbon isotopic composition (?13C) of carbon species in the ocean are characterised by specific isotopic signatures, which vary temporally and regionally, and are thus widely used to understand the marine carbon cycle. However, some important coastal and open ocean regions: upwelling systems, subtropical gyres and regions between subpolar and subtropical gyres, have scant isotopic data available, limiting our understanding of the carbon cycle and influences from anthropogenic CO2 uptake. This thesis utilises the ?13C of dissolved inorganic carbon (DIC) and particulate organic carbon (POC) to better understand carbon cycle processes and the influence of anthropogenic CO2 in the Benguela Upwelling System (BUS), the Porcupine Abyssal Plain (PAP) observatory site and the eastern part of the subtropical gyre of the northeast Atlantic Ocean. In the BUS, the ?13CDIC values and DIC concentrations vary spatially: higher ?13CDIC and low DIC at the Lüderitz Upwelling Cell (LUC) and lower ?13CDIC and high DIC at the southern and northern BUS. The ?13CDIC, DIC and nutrient results indicate that increased biological productivity overrides the effect of low ?13CDIC upwelling waters on the ?13CDIC and DIC distribution at the LUC, whereas the upwelling waters and associated organic matter remineralisation dominate over the effect of biological productivity and control the ?13CDIC and DIC distribution at the NBUS and SBUS. The observed decoupling of ?13CDIC-phosphate and ?13CDIC-apparent oxygen utilization confirm that upwelling waters and the associated remineralisation of organic matter are the main sources and controlling processes of DIC cycling in the BUS. The ?13CPOC distribution in the water column at the PAP site is strongly controlled by biological processes and decreased with depth. A decrease of ?13CPOC in the upper 200 m is attributed to increasing inputs of 13C-depleted POC from the lower euphotic layer, whereas the decrease below 200 m is a result of a greater and preferential degradation of labile, 13C-enriched proteins and carbohydrate components, leaving more refractory, 13C-depleted lipid and lignin components. This study shows that surface water ?13CPOC values are isotopically lower compared to values reported in earlier studies in the northeast Atlantic Ocean (JGOF?S site in 1989 and PAP site in 1997) and are also lower relative to surface sediments, which is attributable to the 13C Suess effect resulting from the uptake of isotopically light anthropogenic CO2. The air-sea exchange signature of ?13C (?13Cas) negatively deviates in surface waters of the subtropical gyre region studied. The relationship of ?13Cas versus temperature derived for the upper 200 m in this gyre in 2020 (?13Cas = -0.027T - 1.773) deviates negatively from that observed in the same region in 1990 (?13Cas = -0.042T - 1.084). These observations confirm that the surface ocean is influenced by anthropogenic CO2. The ?13CDIC in this region has decreased (-0.86 ?, surface waters; -0.83 ?, upper 200 m) during the 27-year period 1993-2020. ?13CDIC has decreased at a faster rate during the 2013-2020 period (0.056 ? per year, surface waters; 0.048 ? per year, upper 200 m) compared to the 1993-2013 period (0.023 ? per year, surface waters; 0.024 ? per year, upper 200 m). This implies that the uptake of anthropogenic CO2 in the upper ocean of this gyre region not only intensified during 1993-2020, but that it accelerated during 2013-2020. More broadly, this study highlights the utility of stable carbon isotopes in studies of short time carbon cycling in upwelling regimes and thus their role in modulating CO2 levels in the ocean-atmosphere system. PB - University of Southampton KW - Eastern Atlantic Ocean KW - Stable carbon isotopes KW - DIC KW - POC M1 - phd TI - Stable carbon isotopes from the Eastern Atlantic Ocean: anthropogenic and biological signals AV - restricted EP - 220 ER - TY - JOUR ID - soton7878 UR - https://eprints.soton.ac.uk/7878/ A1 - Lambshead, P.J.D. A1 - Tietjen, J. A1 - Glover, A. A1 - Ferrero, T. A1 - Thistle, D. A1 - Gooday, A.J. Y1 - 2001/// JF - Marine Ecology Progress Series VL - 214 KW - NEMATODES KW - NORTH ATLANTIC OCEAN KW - BIOLOGY SN - 0171-8630 TI - Impact of large-scale natural physical disturbance on the diversity of deep-sea North Atlantic nematodes SP - 121 AV - none EP - 126 ER - TY - JOUR ID - soton7916 UR - https://eprints.soton.ac.uk/7916/ IS - 1-4 A1 - Lampitt, R.S. A1 - Bett, B.J. A1 - Kiriakoulakis, K. A1 - Popova, E.E. A1 - Ragueneau, O. A1 - Vangriesheim, A. A1 - Wolff, G.A. Y1 - 2001/// N2 - Downward particle flux was measured using sediment traps at various depths over the Porcupine Abyssal Plain (water depth ~4850 m) for prolonged periods from 1989 to 1999. A strong seasonal pattern of flux was evident reaching a maximum in mid-summer. The composition of the material changed with depth, reflecting the processes of remineralisation and dissolution as the material sank through the water column. However, there was surprisingly little seasonal variation in its composition to reflect changes in the biology of the euphotic zone.
Currents at the site have a strong tidal component with speeds almost always less than 15 cm/sec. In the deeper part of the water column they tend to be northerly in direction, when averaged over periods of several months.
A model of upper ocean biogeochemistry forced by meteorology was run for the decade in order to provide an estimate of flux at 3000 m depth. Agreement with measured organic carbon flux is good, both in terms of the timings of the annual peaks and in the integrated annual flux. Interannual variations in the integrated flux are of similar magnitude for both the model output and sediment trap measurements, but there is no significant relationship between these two sets of estimates. No long-term trend in flux is evident, either from the model, or from the measurements.
During two spring/summer periods, the marine snow concentration in the water column was assessed by time-lapse photography and showed a strong peak at the start of the downward pulse of material at 3000 m. This emphasises the importance of large particles during periods of maximum flux and at the start of flux peaks. Time lapse photographs of the seabed show a seasonal cycle of coverage of phytodetrital material, in agreement with the model output both in terms of timing and magnitude of coverage prior to 1996. However, after a change in the structure of the benthic community in 1996 no phytodetritus was evident on the seabed.
The model output shows only a single peak in flux each year, whereas the measured data usually indicated a double peak. It is concluded that the observed double peak may be a reflection of lowered sediment trap efficiency when flux is very high and is dominated by large marine snow particles.
Resuspension into the trap 100 m above the seabed, when compared to the primary flux at 3000 m depth (1800 mab) was lower during periods of high primary flux probably because of a reduction in the height of resuspension when the material is fresh. At 2 mab, the picture is more complex with resuspension being enhanced during the periods of higher flux in 1997, which is consistent with this hypothesis. However there was rather little relationship to flux at 3000 m in 1998.
At 3000 m depth, the Flux Stability Index (FSI), which provides a measure of the constancy of the seasonal cycle of flux, exhibited an inverse relationship with flux, such that the highest flux of organic carbon was recorded during the year with the greatest seasonal variation. JF - Progress in Oceanography VL - 50 KW - particulate flux KW - northeast atlantic ocean KW - seasonality SN - 0079-6611 TI - Material supply to the abyssal seafloor in the northeast Atlantic SP - 27 AV - none EP - 63 ER - TY - JOUR ID - soton63721 UR - https://eprints.soton.ac.uk/63721/ IS - 11 A1 - Lampitt, R.S. A1 - Boorman, B. A1 - Brown, L. A1 - Lucas, M. A1 - Salter, I. A1 - Sanders, R. A1 - Saw, K. A1 - Seeyave, S. A1 - Thomalla, S.J. A1 - Turnewitsch, R. Y1 - 2008/11// N2 - We describe the first results obtained using a novel free-drifting neutrally buoyant sediment trap called PELAGRA (Particle Export measurement using a LAGRAngian trap). The trap uses an APEX float (Autonomous Profiling EXplorer) to maintain its location at a predetermined depth or density horizon and is designed to be deployed in the depth range 100?600 m for periods of up to a week. PELAGRA was deployed into a well characterised region of the Northeast (NE) Atlantic over the Porcupine Abyssal Plain (PAP) during the summers of 2003, 2004, 2005 and 2006 in post-bloom conditions. In parallel, measurements were made of total and new primary production and estimates of particle export based on 234Th deficits in the upper water column. Samples of sinking material from PELAGRA were recovered almost uncontaminated by ?swimmers?. The material collected differed from that obtained using water bottles and an in situ filtration system and this indicated selective export of centric diatoms. Fluxes of 234Th into the traps were less than that calculated from the deficit of this isotope in the upper water column. It is concluded that this reflects export events that had occurred prior to these deployments. Fluxes of organic carbon into the PELAGRA traps were similar to those expected from measurements of new production in the upper mixed layer. During 2006, simultaneous PELAGRA deployments at depths of 150 and 250 m provided a direct measurement of the decrease in flux with depth. This decrease was substantially more than that predicted by the often-used ?Martin equation? and yielded a ?b value? of 1.7. Using this value in the NE Atlantic about 14% of the total production reaches a depth of 150 m during the post-bloom period under nutrient limitation.

JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 55 KW - particle flux KW - thorium-234 KW - carbon export KW - biogeochemistry KW - sediment trap KW - northeast atlantic SN - 0967-0637 TI - Particle export from the euphotic zone: estimates using a novel drifting sediment trap, 234Th and new production SP - 1484 AV - none EP - 1502 ER - TY - JOUR ID - soton2118 UR - https://eprints.soton.ac.uk/2118/ IS - 9 A1 - Lavin, A.M. A1 - Bryden, H.L. A1 - Parrilla, G. Y1 - 2003/// N2 - Hydrographic data from a cruise at 24.5°N in the subtropical North Atlantic are used to calculate and examine the fluxes across the section. The components of the fluxes of heat, freshwater, oxygen and nutrients through the section are analysed. After the variables are separated into section average, baroclinic profile and anomalies, the fluxes are separated into an Ekman component and its barotropic compensation, baroclinic and horizontal components. The baroclinic contribution due to the meridional overturning circulation (MOC) is responsible for the largest amount of heat transport with warmer waters flowing poleward and cooler deep waters flowing equatorward. The Ekman component and its barotropic compensation is the second-most important component of heat transport. The MOC transports about 25% of the combined meridional heat transport by atmosphere and ocean at 24°N. The Ekman and baroclinic components are responsible for the northward salt transport. Salt conservation for the Atlantic north of 24.5°N suggests that there is a net precipitation between the Bering Strait and the 24.5°N section of about 0.5 Sv. Horizontal transport is the major contribution to the southward oxygen flux, as oxygen-poor water flows northward in the Florida Straits and oxygen-rich water flows southward in mid-ocean. Baroclinic transport is the main factor in the southward transport of all nutrients: low concentration upper water flows northward and higher concentration deep water flows southward.
The zonally integrated meridional cell carries a poleward heat flux of 1.51±0.39 PW, 0.14 PW of which is due to seasonal sampling, and equatorward transports of -2621±705 kmol s-1 of oxygen, -254±176 kmol s-1 of silicate, -130±95 kmol s-1 of nitrate and -12.6±6.3 kmol s-1 of phosphate.
Finally we have explored the changes in ocean circulation implied by changes in silicate transport through the section. Strict silicate conservation through the section leads to a great increase in the northward deep circulation in the eastern basin that is not in accord with the present understanding of the circulation. Taking an intermediate silicate transport through the section, according to estimates of silicate sources, produces a reasonable increase in the southward Deep Western Boundary Current (DWBC) flow and an increase in the deep northward transport in the eastern deep basin, as well as a decrease in silicate and nitrate transports through the section. Fluxes of heat, salt and oxygen are not significantly affected by changes in the conditions of silicate conservation. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 50 KW - Atlantic circulation KW - Freshwater transport KW - Meridional overturning KW - Nutrient transport KW - Ocean heat transport KW - Oxygen transport KW - Subtropical North Atlantic Ocean SN - 0967-0637 TI - Mechanisms of heat, freshwater, oxygen and nutrient transports and budgets at 24.5°N in the subtropical North Atlantic SP - 1099 AV - none EP - 1128 ER - TY - JOUR N1 - Funding Information: We gratefully acknowledge the U.S. National Science Foundation: This work was supported by Grants OCE-1258823 and OCE-1756272. M. F. d J. was supported by NIOZ and EU Horizon 2020 project Blue-Action (Grant 727852). N. P. H. was supported by NERC program UK OSNAP (NE/K010875/1), UK OSNAP-Decade (NE/T00858X/1), and ACSIS (National Capability). The U.S. Cape Farewell OSNAP data reported here are available from this site (doi:10.7924/r4fb50z9b). The UK data are available here (doi:10.5285/8c232969-11cd-3e52-e053-6c86abc07963). OOI data were obtained from the NSF Ocean Observatories Initiative Data Portal, http://ooinet.oceanobservatories.org, downloaded on 9 August 2017. EN4 data were downloaded from https://www.metoffice.gov.uk/hadobs/en4/download-en4-2-1.html on 26 October 2018. The Argo float mixed layer climatology shown in the supporting information is described in Holte et al. () and was downloaded from mixedlayer.ucsd.edu on 20 November 2019. We thank M. Spall, R. Pickart, and A. Pacini for helpful scientific discussions, and F. Li and M.S. Lozier for providing the gridded velocity field across the OSNAP line (doi:10.7924/r4z60gf0f). The data presented in this manuscript would not have come about without the hard work of the entire OSNAP team, especially all scientists, technical staff, and crew who went to sea to collect these data. Publisher Copyright: ©2020. The Authors. ID - soton438095 UR - https://eprints.soton.ac.uk/438095/ IS - 3 A1 - Le Bras, I. A.?A. A1 - Straneo, F. A1 - Holte, J. A1 - Jong, M. F. A1 - Holliday, N. P. Y1 - 2020/02/16/ N2 -

The standard view of the overturning circulation emphasizes the role of convection, yet for waters to contribute to overturning, they must not only be transformed to higher densities but also exported equatorward. From novel mooring observations in the Irminger Sea (2014?2016), we describe two water masses that are formed by convection and show that they have different rates of export in the western boundary current. Upper Irminger Sea Intermediate Water appears to form near the boundary current and is exported rapidly within 3 months of its formation. Deep Irminger Sea Intermediate Water forms in the basin interior and is exported on longer time scales. The subduction of these waters into the boundary current is consistent with an eddy transport mechanism. Our results suggest that light intermediate waters can contribute to overturning as much as waters formed by deeper convection and that the export time scales of both project onto overturning variability.

JF - Geophysical Research Letters VL - 47 KW - North Atlantic KW - convection KW - eddy processes KW - high latitude KW - overturning KW - subpolar circulation SN - 0094-8276 TI - Rapid export of waters formed by convection near the Irminger Sea's western boundary AV - public ER - TY - JOUR ID - soton366212 UR - https://eprints.soton.ac.uk/366212/ IS - 13 A1 - Le Moigne, Frédéric A.C. A1 - Moore, C. Mark A1 - Sanders, Richard J. A1 - Villa-Alfageme, Maria A1 - Steigenberger, Sebastian A1 - Achterberg, Eric P. Y1 - 2014/07/16/ N2 - Estimates of the amount of carbon sequestered in the ocean interior per unit iron (Fe) supplied, as quantified by the sequestration efficiency (Ceffx), vary widely. Such variability in Ceffx has frequently been attributed to estimate uncertainty rather than intrinsic variability. Here we derive new estimates of Ceffx for the subpolar North Atlantic, where Fe stressed conditions have recently been demonstrated. Derived values of Ceffx from across the region, including areas subject to atypical external Fe fertilization events during the year of sample collection (2010), ranged from 17 - 19 kmol C (mol Fe-1). Comparing these estimates with values from other systems, considered in the context of variable bloom durations in the different oceanographic settings, we suggest that apparent variability in Ceffx may be related to the mode of Fe delivery. JF - Geophysical Research Letters VL - 41 KW - carbon export KW - North Atlantic KW - Iron limitation SN - 0094-8276 TI - Sequestration efficiency in the iron limited North Atlantic: Implications for iron supply mode to fertilized blooms SP - 4619 AV - public EP - 4627 ER - TY - JOUR ID - soton63939 UR - https://eprints.soton.ac.uk/63939/ IS - 8 A1 - LeBel, Deborah A. A1 - Smethie, William M. A1 - Rhein, Monika A1 - Kieke, Dagmar A1 - Fine, Rana A. A1 - Bullister, John L. A1 - Min, Dong-Ha A1 - Roether, Wolfgang A1 - Weiss, Ray F. A1 - Andrié, Chantal A1 - Smythe-Wright, Denise A1 - Jones, E. Peter Y1 - 2008/08// N2 - The accumulation of man-made chlorofluorocarbons (CFCs) in subsurface water masses is directly related to their formation rate, and the water mass formation rate can be calculated from its CFC inventory. CFC-11 inventories between 65°N and 10°S in the Atlantic Ocean have been calculated for Eighteen Degree Water (EDW) and the components of North Atlantic Deep Water (NADW) from data collected primarily between 1996 and 1998 as part of the World Ocean Circulation Experiment (WOCE). CFC-11 inventories for individual water masses are 5.4 million moles for EDW, 10.5 million moles for Upper Labrador Sea Water (ULSW) (4.6 million moles south of 42°N), 23.4 million moles for Classical Labrador Sea Water (CLSW), 10.4 million moles for Iceland-Scotland Overflow Water (ISOW), and 8.3 million moles for Denmark Strait Overflow Water (DSOW). The estimated error for these inventories is about ±10%. The sum of the NADW components (ULSW, CLSW, ISOW, DSOW) is 53.2 million moles which is about half of the total CFC-11 inventory, 103.8 million moles, in the North Atlantic Ocean. Maps of water column inventories illustrate the formation mechanisms and spreading pathways within these water masses. The inventories directly reflect the input of newly formed water in the North Atlantic over the time scale of the CFC transient, about 3 decades. The interior regions of the North Atlantic contain most (75?80%) of the CFC-11 inventory in NADW indicating strong recirculation and mixing of newly formed NADW from the DWBC into the interior with a time scale of 2?3 decades. Average water mass formation rates between 1970 and 1997 are: 3.3 Sv for EDW, 3.5 Sv for ULSW (2.0 Sv from the central Labrador Sea and 1.5 Sv from the southern Labrador Sea), 8.2 Sv for CLSW, 5.7 Sv for ISOW, and 2.2 Sv for DSOW. Estimated errors are ±20% for CLSW and ±16% for the other water masses. The total for NADW, which forms the deep limb of the North Atlantic Meridional Overturning Circulation, is 19.6 Sv. An extensive test of the effects of temporal variability on the average formation rate calculated from the CFC inventory indicates that the error introduced by the assumption of a constant water mass formation rate is no greater than 15% for CLSW and 10% for the other water masses.
JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 55 KW - North Atlantic Deep Water KW - Eighteen Degree Water KW - CFCs KW - Formation rate KW - Circulation SN - 0967-0637 TI - The formation rate of North Atlantic Deep Water and Eighteen Degree Water calculated from CFC-11 inventories observed during WOCE SP - 891 AV - none EP - 910 ER - TY - RPRT ID - soton305 UR - https://eprints.soton.ac.uk/305/ A1 - Leach, H. A1 - Pollard, R.T. Y1 - 1998/// N2 - RRS Discovery Cruise 223, VIVALDI ?96, was a contribution to the UK WOCE Community Research Programme. The pattern of SeaSoar sections was designed to enable the upper ocean circulation in the Subpolar gyre of the North Atlantic to be mapped and in particular the course of the North Atlantic and Irminger Currents within the region to be determined. The sparse deep CTD survey was required to complement the upper ocean survey and provide estimates of total mass transport and an ?oceanographic opinion poll? of water mass properties, including CFCs.

The cruise commenced by repeating the well-established Rockall Trough CTD Section from Barra Head to Rockall Island. This was then extended north to Lousy Bank from where a CTD section measured before by Saunders across the Iceland Basin was repeated. From then onwards the cruise consisted principally of SeaSoar/ADCP sections interspersed with deep CTD casts (see track plot, Fig.1). These were placed on the ?Vivaldi Grid? (round 3° of latitude and multiples of 300 km west of 20°W) where possible, though the complex topography was taken into account. East of Greenland a more intense CTD section of 6 stations (12995-13001) was made along 60°N to cut the East Greenland Current. In addition 7 profiling floats were deployed in the Irminger Basin. PB - Southampton Oceanography Centre, University of Southampton T3 - 17 KW - ADCP KW - cruise 223 1996 KW - CTD observations KW - Discovery KW - East Greenland Current KW - Irminger Basin KW - Lousy Bank KW - North Atlantic Subpolar Gyre KW - Rockall Trough KW - SEASOAR KW - VIVALDI 96 KW - WOCE KW - zooplankton M1 - project_report TI - RRS Discovery Cruise 223, 28 Sep-19 Nov 1996. VIVALDI ?96 AV - public EP - 68 ER - TY - JOUR ID - soton49734 UR - http://www.agu.org/pubs/crossref/2007/2007GL029957.shtml IS - 12 A1 - Leadbetter, S.J. A1 - Williams, R.G. A1 - McDonagh, E.L. Y1 - 2007/06/26/ N2 - Temperature and salinity changes have been compared along three repeat sections at 36°N in the North Atlantic. The principal changes, cooling of the upper waters and warming of the intermediate waters observed between 1959 and 1981, were reversed between 1981 and 2005. The controlling mechanisms for the changes over the two time periods differed through the water column. Neutral density surfaces over the upper 800 m were firstly uplifted and secondly depressed by typically 50 m, which is broadly consistent with the changes in thermocline thickness implied by the temporal changes in Ekman pumping. In contrast, the intermediate waters (800?2500 m) firstly became warmer and saltier and secondly became cooler and fresher. This change in the intermediate waters was controlled by water mass changes along neutral density surfaces suggesting a change in the source waters, principally Labrador Sea Water and Mediterranean Outflow Water. JF - Geophysical Research Letters VL - 34 KW - decadal change KW - hydrographic data KW - North Atlantic SN - 0094-8276 TI - A twenty year reversal in water mass trends in the subtropical North Atlantic AV - none ER - TY - JOUR ID - soton422985 UR - https://eprints.soton.ac.uk/422985/ IS - 7 A1 - Lehrmann, Berit A1 - Stobbs, Iain J. A1 - Lusty, Paul A.J. A1 - Murton, Bramley J. Y1 - 2018/07/18/ N2 -

Over the last decade there has been an increasing interest in deep-sea mineral resources that may contribute to future raw metal supply. However, before seafloor massive sulfides (SMS) can be considered as a resource, alteration and weathering processes that may affect their metal tenor have to be fully understood. This knowledge cannot be obtained by assessing the surface exposures alone. Seafloor drilling is required to gain information about the third dimension. In 2016, three extinct seafloor massive sulfide mounds, located in the Trans-Atlantic Geotraverse (TAG) hydrothermal area of the Mid-Atlantic Ridge were drilled. A mineralogical and textural comparison of drill core and surface-grab samples revealed that in recent ceased mounds high-temperature copper assemblages typical for black smoker chimneys are still present whereas in longer extinct mounds the mineralogy is pre-dominated by an iron mineral assemblage. Zinc becomes remobilized early in the mound evolution and forms either a layer in the upper part of the mound or has been totally leached from its interior. Precipitation temperatures of sphalerite calculated using the Fe/Zn ratio can help to identify these remobilization processes. While the Fe/Zn ratios of primary sphalerites yield temperatures that are in very good agreement with fluid temperatures measured in white smokers, calculated temperatures for sphalerites affected by remobilization are too high for SMS. Overall drilling of SMS provides valuable information on the internal structure and mineralogy of the shallow sub-surface, however, additional drilling of SMS, at a greater depth, is required to fully understand the processes affecting SMS and their economic potential.

JF - Minerals VL - 8 KW - Drilling KW - Extinct seafloor massive sulfides KW - Mid-Atlantic Ridge KW - TAG hydrothermal area SN - 0009-8558 TI - Insights into extinct seafloor massive sulfide mounds at the TAG, mid-atlantic ridge AV - public ER - TY - JOUR ID - soton65084 UR - https://eprints.soton.ac.uk/65084/ IS - 1890 A1 - Lenton, Timothy M. A1 - Myerscough, Richard J. A1 - Marsh, Robert A1 - Livina, Valerie N. A1 - Price, Andrew R. A1 - Cox, Simon J. Y1 - 2009/03/13/ N2 - We have used the Grid ENabled Integrated Earth system modelling framework to study the archetypal example of a tipping point in the climate system; a threshold for the collapse of the Atlantic thermohaline circulation (THC). eScience has been invaluable in this work and we explain how we have made it work for us. Two stable states of the THC have been found to coexist, under the same boundary conditions, in a hierarchy of models. The climate forcing required to collapse the THC and the reversibility or irreversibility of such a collapse depends on uncertain model parameters. Automated methods have been used to assimilate observational data to constrain the pertinent parameters. Anthropogenic climate forcing leads to a robust weakening of the THC and increases the probability of crossing a THC tipping point, but some ensemble members collapse readily, whereas others are extremely resistant. Hence, we test general methods that have been developed to directly diagnose, from time-series data, the proximity of a ?tipping element?, such as the THC to a bifurcation point. In a three-dimensional ocean?atmosphere model exhibiting THC hysteresis, despite high variability in the THC driven by the dynamical atmosphere, some early warning of an approaching tipping point appears possible. JF - Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences VL - 367 KW - escience KW - earth system modelling KW - climate change KW - atlantic thermohaline circulation KW - tipping point KW - early warning SN - 1364-503X TI - Using GENIE to study a tipping point in the climate system SP - 871 AV - public EP - 884 ER - TY - JOUR N1 - Funding Information: C.A. Rychert, N. Harmon and K. Leptokaropoulos acknowledge funding from the Natural Environment Research Council (NE/M003507/1) and the European Research Council (GA 638665). J.?M. Kendall was funded by the Natural Environment Research Council (NE/M004643/1). D. Schlaphorst was supported by the Portuguese Science and Technology Foundation (FCT/Fundação para a Ciência e Tecnologia), under project PTDC/CTA?GEF/30264/2017 and UIDB/50019/2020 ? IDL. We thank the captain and crew of the R/V and the RRS , and also the scientific technicians. We thank William Wilcock and an anonymous reviewer, the Associate Editor and Editor, Rachel Abercrombie, for their insightful suggestions and comments. Marcus G. Langseth Discovery Funding Information: C.A. Rychert, N. Harmon and K. Leptokaropoulos acknowledge funding from the Natural Environment Research Council (NE/M003507/1) and the European Research Council (GA 638665). J.-M. Kendall was funded by the Natural Environment Research Council (NE/M004643/1). D. Schlaphorst was supported by the Portuguese Science and Technology Foundation (FCT/Funda??o para a Ci?ncia e Tecnologia), under project PTDC/CTA-GEF/30264/2017 and UIDB/50019/2020 ? IDL. We thank the captain and crew of the R/V Marcus G. Langseth and the RRS Discovery, and also the scientific technicians. We thank William Wilcock and an anonymous reviewer, the Associate Editor and Editor, Rachel Abercrombie, for their insightful suggestions and comments. Publisher Copyright: © 2021. The Authors. ID - soton451316 UR - https://eprints.soton.ac.uk/451316/ IS - 9 A1 - Leptokaropoulos, K. A1 - Harmon, N. A1 - Hicks, S. P. A1 - Rychert, C. A. A1 - Schlaphorst, D. A1 - Kendall, J. M. Y1 - 2021/09// N2 -

The gravitational pulls from the moon and the sun result in tidal forces which influence both Earth's solid and water mass. These stresses are periodically added to the tectonic ones and may become sufficient for initiating rupture in fault systems critically close to failure. Previous research indicates correlations between increased seismicity rates and low tides for fast- and intermediate-spreading mid-ocean ridges in the Pacific Ocean. Here, we present a microseismicity data set (4,719 events) recorded by an ocean bottom seismometer deployment at the equatorial Mid-Atlantic Ridge. We show that low, as well as decreasing ocean water level, result in relatively elevated seismicity rates at higher magnitudes (lower b-values), translated into increased probabilities of stronger event occurrence at or towards low tides. Moreover, seismic bursts (enhanced activity rate clusters), occurring at rates well above the reference seismicity, are exclusively present during values of either high tidally induced extensional stresses or high extensional stress rates. Although the b-value differences are not significant enough to be conclusive, the seismicity rate variations exhibit statistical significance, supporting the previous findings for tidal triggering at low tides within normal-faulting regimes and extending the range of observations to slow-spreading ridges. Observed triggering of slip on low angle faults at low tides is predicted by Coulomb stress modeling. The triggering of slip on high angle faults observed here, is not easily explained without another factor. It may be related to the presence of a shallow magma body beneath the ridge, as supported by previous seismic imaging in the region.

JF - Journal of Geophysical Research: Solid Earth VL - 126 KW - Coulomb stress KW - Mid-Atlantic Ridge KW - b-values KW - magnitude distribution KW - seismicity KW - tidal triggering SN - 2169-9313 TI - Tidal triggering of microseismicity at the equatorial mid-atlantic ridge, inferred from the PI-LAB experiment AV - none ER - TY - JOUR N1 - Funding Information: K. Leptokaropoulos, C. A. Rychert, and N. Harmon acknowledge funding from the Natural Environment Research Council (NE/M003507/1) and the European Research Council (GA 638665). J. M. Kendall was funded by the Natural Environment Research Council (NE/M004643/1). We thank the captain and crew of the R/V Marcus G. Langseth and the RRS Discovery, and the scientific technicians. We thank David Schlaphorst for discussions on magnitudes and focal mechanisms calculation. We thank Jochen Braunmiller and an anonymous reviewer, the Associate Editor, and Editor, Satoshi Ide, for their insightful comments and suggestions. Publisher Copyright: © 2023. The Authors. ID - soton475676 UR - https://eprints.soton.ac.uk/475676/ IS - 3 A1 - Leptokaropoulos, Konstantinos A1 - Rychert, Catherine A1 - Harmon, Nicholas A1 - Kendall, J. Michael Y1 - 2023/03// N2 - Oceanic transform faults are intriguing in that they do not produce earthquakes as large as might be expected given their dimensions. We use 1-year of local seismicity (370 events above MC = 2.3) recorded on an array of ocean bottom seismometers (OBSs) and geophysical data to study the seismotectonic properties of the Chain transform, located in the equatorial Mid-Atlantic. We extend our analysis back in time by considering stronger earthquakes (MW ? 5.0) from global catalogs. We divide Chain into three areas (east, central, and west) based on historical event distribution, morphology, and multidimensional OBS seismicity cluster analysis. Seismic activity recorded by the OBS is the highest at the eastern area of Chain where there is a lozenge-shaped topographic high, a negative rMBA gravity anomaly, and only a few historical MW ? 5.5 events. OBS seismicity rates are lower in the western and central areas. However, these areas accommodate the majority of seismic moment release, as inferred from both OBS and historical data. Higher b-values are significantly correlated with lower rMBA and with shallower bathymetry, potentially related to thickened crust. Our results suggest high lateral heterogeneity along Chain. Patches with moderate to low OBS seismicity rates that occasionally host MW ? 6.0 earthquakes are interrupted by segments with abundant OBS activity but few historical events with 5.5 ? MW < 6.0. This segmentation is possibly due to variable fluid circulation and alteration, which may also change in time. JF - Journal of Geophysical Research: Solid Earth VL - 128 KW - Mid Atlantic Ridge KW - OBS seismicity KW - fault segmentation KW - oceanic transform faults KW - seismotectonics SN - 2169-9356 TI - Seismicity properties of the Chain Transform Fault inferred using data from the PI-LAB experiment AV - public EP - 16 ER - TY - JOUR ID - soton357324 UR - https://eprints.soton.ac.uk/357324/ IS - 3 A1 - Levine, Naomi Marcil A1 - Doney, Scott C. A1 - Lima, Ivan A1 - Wanninkhof, Rik A1 - Bates, Nicholas R. A1 - Feely, Richard A. Y1 - 2011/// N2 - The North Atlantic Ocean accounts for about 25% of the global oceanic anthropogenic carbon sink. This basin experiences significant interannual variability primarily driven by the North Atlantic Oscillation (NAO). A suite of biogeochemical model simulations is used to analyze the impact of interannual variability on the uptake and storage of contemporary and anthropogenic carbon (Canthro) in the North Atlantic Ocean. Greater winter mixing during positive NAO years results in increased mode water formation and subsequent increases in subtropical and subpolar Canthro inventories. Our analysis suggests that changes in mode water Canthro inventories are primarily due to changes in water mass volumes driven by variations in water mass transformation rates rather than local air-sea CO2 exchange. This suggests that a significant portion of anthropogenic carbon found in the ocean interior may be derived from surface waters advected into water formation regions rather than from local gas exchange. Therefore, changes in climate modes, such as the NAO, may alter the residence time of anthropogenic carbon in the ocean by altering the rate of water mass transformation. In addition, interannual variability in Canthro storage increases the difficulty of Canthro detection and attribution through hydrographic observations, which are limited by sparse sampling of subsurface waters in time and space. JF - Global Biogeochemical Cycles VL - 25 KW - North Atlantic Oscillation KW - anthropogenic carbon KW - carbon cycle KW - climate change KW - global climate model KW - mode waters SN - 0886-6236 TI - The impact of the North Atlantic Oscillation on the uptake and accumulation of anthropogenic CO2by North Atlantic Ocean mode waters AV - none ER - TY - JOUR ID - soton50320 UR - http://www.agu.org/journals/jc/jc0707/2006JC003716/ IS - 7 A1 - Lherminier, P. A1 - Mercier, H. A1 - Gourcuff, C. A1 - Alvarez, M. A1 - Bacon, S. A1 - Kermabon, C. Y1 - 2007/07/04/ N2 - The first Ovide cruise occurred in June?July 2002 on R/V Thalassa between Greenland and Portugal. The absolute transports across the Ovide line are estimated using a box inverse model constrained by direct acoustic Doppler current profiler velocity measurements and by an overall mass balance (±3 Sv, where 1 Sv = 106 m3 s?1) across the section. Main currents are studied and compared to the results of the similar Fourex section performed in August 1997 and revisited here. The meridional overturning cell (MOC) is estimated in two different ways, both leading to a significantly lower value in June 2002 than in August 1997, consistent with the relative strength of the main components of the MOC (North Atlantic Current and deep western boundary current). It has been found that the MOC calculated on density levels is more robust and meaningful than when calculated on depth levels, and it is found to be 16.9 ± 1.0 Sv in 2002 versus 19.2 ± 0.9 Sv in 1997. The 2002 heat transport of 0.44 ± 0.04 × 1015 W is also significantly different from the 0.66 ± 0.05 × 1015 W found in 1997, but it is consistent with the much weaker integrated warm water transport across the section than in 1997. JF - Journal of Geophysical Research VL - 112 KW - North Atlantic circulation KW - meridional overturning cell KW - hydrographic section SN - 0148-0227 TI - Transports across the 2002 Greenland-Portugal Ovide section and comparison with 1997 AV - none ER - TY - JOUR ID - soton360976 UR - https://eprints.soton.ac.uk/360976/ A1 - Linley, Thomas D. A1 - Alt, Claudia H.S. A1 - Jones, Daniel O.B. A1 - Priede, Imants G. Y1 - 2013/12/15/ N2 - Demersal fish were assessed by remotely operated vehicle (ROV) video transects at sites to the NE, NW (54°N), SE and SW (49°N) of the Charlie-Gibbs Fracture Zone (CGFZ) at ca. 2500 m depth on the Mid-Atlantic Ridge. At each site, three different slope categories (flat, 10° slope and >30° slope) were sampled with four transects, each surveying 2000 m3 of suprabenthic water. This resulted in 12 high-definition video transects at every site, covering a total of 24,000 m3 suprabenthic water. Six species were observed; which was fewer than in surveys using baited landers (19 species) and trawls (26 species) in the same area. Bathysaurus ferox, Halosauropsis macrochir, Antimora rostrata and Polyacanthonotus challengeri did not vary in density between sites, while Coryphaenoides brevibarbis and Coryphaenoides armatus were significantly more abundant at the northern sites; the latter supporting findings using baited landers. The halosaur H. macrochir was the only species affected by slope. The majority of observed fish showed no reaction to one or more of the stimuli produced by the ROV, however burst swimming was observed at least once in all species except B. ferox. The most abundant species, C. brevibarbis, was particularly affected by the presence of the ROV. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 98 KW - ECOMAR KW - Mid-Atlantic Ridge KW - Charlie-Gibbs Fracture Zone KW - ROV video transect KW - Sampling bias KW - Fish KW - Demersal KW - Density KW - Abundance KW - Reaction SN - 0967-0645 TI - Bathyal demersal fishes of the Charlie-Gibbs Fracture Zone region (49°?54°N) of the Mid-Atlantic Ridge: III. Results from remotely operated vehicle (ROV) video transects SP - 407 AV - none EP - 411 ER - TY - JOUR ID - soton424465 UR - https://eprints.soton.ac.uk/424465/ A1 - Little, Susan H. A1 - Archer, Corey A1 - Milne, Angela A1 - Schlosser, Christian A1 - Achterberg, Eric P. A1 - Lohan, Maeve C. A1 - Vance, Derek Y1 - 2018/07/21/ N2 -

Copper (Cu) is both an essential micronutrient and toxic to photosynthesizing microorganisms at low concentrations. Its dissolved vertical distribution in the oceans is unusual, being neither a nutrient-type nor scavenged-type element. This distribution is attributed to biological uptake in the surface ocean with remineralisation at depth, combined with strong organic complexation by dissolved ligands, scavenging onto particles, and benthic sedimentary input. We present coupled dissolved and particulate phase Cu isotope data along the UK-GEOTRACES South Atlantic section, alongside higher resolution dissolved and particulate phase Cu concentration measurements. Our dissolved phase isotope data contribute to an emerging picture of homogeneous deep ocean ?65Cu, at about +0.65? (relative to NIST SRM 976). We identify two pools of Cu in the particulate phase: a refractory, lithogenic pool, at about 0?, and a labile pool accessed via a weak acidic leach, at about +0.4?. These two pools are comparable to those previously observed in sediments. We observe deviations towards lighter ?65Cu values in the dissolved phase associated with local enrichments in particulate Cu concentrations along the continental slopes, and in the surface ocean. Copper isotopes are thus a sensitive indicator of localised particle-associated benthic or estuarine Cu inputs. The measurement of Cu isotopes in seawater is analytically challenging, and we call for an intercalibration exercise to better evaluate the potential impacts of UV-irradiation, storage time, and different analytical procedures.

JF - Chemical Geology VL - 502 KW - Copper isotopes KW - Dissolved KW - GEOTRACES KW - Particulate KW - South Atlantic SN - 0009-2541 TI - Paired dissolved and particulate phase Cu isotope distributions in the South Atlantic SP - 29 AV - public EP - 43 ER - TY - JOUR ID - soton357251 UR - https://eprints.soton.ac.uk/357251/ A1 - Lomas, M.W. A1 - Bates, N.R. A1 - Johnson, R.J. A1 - Knap, A.H. A1 - Steinberg, D.K. A1 - Carlson, C.A. Y1 - 2013/09// N2 - The Bermuda Atlantic Time-series Study (BATS) program has sampled the northwestern Sargasso Sea on a biweekly (January to April) to monthly basis since October 1988. The primary objective of the core BATS program continues to be an improved understanding of the time-variable processes and mechanisms that control the biogeochemical cycling of carbon and related elements in the surface ocean. With 24 years of measurements for most chemical, physical and biological variables, we have moved beyond descriptions of seasonal and interannual variability to examination of multi-year trends and potential controls, however there remain substantial gaps in our knowledge of the ecosystem mechanisms related to organic matter production, export and remineralization. While earlier BATS overviews have focused on describing seasonal and year-to-year variability, this overview provides new information on three long-standing biogeochemical questions in Sargasso Sea biogeochemistry. First, why is there a discrepancy between biological (i.e., sediment trap) and geochemical estimates of carbon export production? Winter storms and mesoscale eddies have now been clearly shown to contribute to annual nutrient budgets and carbon export production. Recent information on phytoplankton natural isotopic nitrogen composition, and data from profiling floats suggests that small phytoplankton are important contributors to new production in summer despite the apparent absence of a mechanism to entrain nitrate into the euphotic zone. These findings aid in closing the gap between these two different estimates of carbon export production. Second, what supports the seasonal drawdown of carbon dioxide in the absence of detectable nutrients? The zooplankton timeseries at BATS highlights the importance of zooplankton as a conduit for carbon removal due to grazing and vertical migration. Although increases in cellular elemental stoichiometry to values greater than the canonical Redfield Ratio, and the seasonal (and interannual) accumulation of euphotic zone dissolved organic carbon (DOC) without accumulation of DON in the surface ocean are also important explanations. Lastly, what are the sources of the elevated nitrate to phosphate ratio in the seasonal thermocline (N:P>30 on average)? While generally accepted that nitrogen fixation is the source of the additional nitrogen, new research suggests that export and remineralization of non-diazotroph particulate matter enriched in nitrogen (alternatively viewed as depleted in phosphorus) may also make substantial contributions. In addition, the ratio of particulate nitrogen to phosphorus captured in sediment traps has decreased from 50?75 to <50, possibly due to enhanced nitrogen remineralization. These and other findings from the core BATS observational program contribute to our improved understanding of biogeochemical cycles and ecosystem mechanisms in the subtropical North Atlantic Ocean and how they are changing over time. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 93 KW - Bermuda Atlantic Time-series Study KW - Sargasso Sea KW - Carbon cycle KW - Biogeochemistry KW - Primary production KW - Zooplankton SN - 0967-0645 TI - Two decades and counting: 24-years of sustained open ocean biogeochemical measurements in the Sargasso Sea SP - 16 AV - none EP - 32 ER - TY - JOUR ID - soton358303 UR - https://eprints.soton.ac.uk/358303/ IS - 11 A1 - Lomas, Michael W. A1 - Bates, Nicholas R. Y1 - 2004/11// N2 - Seasonal dissolved organic carbon (DOC) accumulation and potential subsequent export, in addition to particulate organic carbon (POC) gravitational export, can be an important pathway of carbon removal from the surface ocean (>100 m) at the Bermuda Atlantic Time-series Study (BATS). We have compiled available data on seasonal DOC accumulation and POC flux during the course of the winter/spring bloom and examined some potential controls on the interannual variability of organic carbon partitioning between these two fates. When expressed as a fraction of the cumulative primary production, there was a significant negative relationship between seasonal DOC accumulation and POC flux. Over the course of the BATS data record two groups of phytoplankton, Haptophytes and Prochlorophytes, account for ?60% of the integrated (0?140 m) chlorophyll biomass. Variability in the relative abundance of Haptophytes and Prochlorophytes was significantly correlated to the export of carbon, with increased relative abundance of Haptophytes correlated with higher seasonal accumulation of DOC and lower POC fluxes. Variability in the abundance of Haptophytes during the winter/spring period was found to correlate negatively with the winter North Atlantic Oscillation (NAO) index. This relationship suggests that Haptophytes are a more important component of the phytoplankton community when a negative NAO phase enhances winter/spring mixing in the Sargasso Sea. These findings support a recent hypothesis that the increased stratification in the North Atlantic due to global warming could favor the blooming of diatoms over Haptophytes. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 51 KW - DOC KW - Carbon flux KW - Biological pump KW - Bermuda Atlantic time series KW - Sargasso Sea SN - 0967-0637 TI - Potential controls on interannual partitioning of organic carbon during the winter/spring phytoplankton bloom at the Bermuda Atlantic time-series study (BATS) site SP - 1619 AV - none EP - 1636 ER - TY - JOUR ID - soton415159 UR - https://eprints.soton.ac.uk/415159/ A1 - Longman, Jack A1 - Ersek, Vasile A1 - Veres, Daniel A1 - Salzmann, Ulrich Y1 - 2017/07/01/ N2 -

The Romanian Carpathians are located at the confluence of three major atmospheric pressure fields: the North Atlantic, the Mediterranean and the Siberian. Despite its importance for understanding past human impact and climate change, high-resolution palaeoenvironmental reconstructions of Holocene hydroclimate variability, and in particular records of extreme precipitation events in the area, are rare. Here we present a 7500-year-long high-resolution record of past climatic change and human impact recorded in a peatbog from the Southern Carpathians, integrating palynological, geochemical and sedimentological proxies. Natural climate fluctuations appear to be dominant until 4500 years before present (yr BP), followed by increasing importance of human impact. Sedimentological and geochemical analyses document regular minerogenic deposition within the bog, linked to periods of high precipitation. Such minerogenic depositional events began 4000 yr BP, with increased depositional rates during the Medieval Warm Period (MWP), the Little Ice Age (LIA) and during periods of societal upheaval (e.g. the Roman conquest of Dacia). The timing of minerogenic events appears to indicate a teleconnection between major shifts in North Atlantic Oscillation (NAO) and hydroclimate variability in southeastern Europe, with increased minerogenic deposition correlating to low NAO index values. By linking the minerogenic deposition to precipitation variability, we state that this link persists throughout the mid-to-late Holocene.

JF - Quaternary Science Reviews VL - 167 KW - Carpathians KW - Holocene KW - Hydroclimate KW - North Atlantic Oscillation KW - Peatbog KW - Pollen KW - Romania SN - 0277-3791 TI - Detrital events and hydroclimate variability in the Romanian Carpathians during the mid-to-late Holocene SP - 78 AV - public EP - 95 ER - TY - JOUR ID - soton197059 UR - https://eprints.soton.ac.uk/197059/ A1 - Longmore, C. A1 - Trueman, C.N. A1 - Neat, F. A1 - O?Gorman, E.J. A1 - Milton, J.A. A1 - Mariani, S. Y1 - 2011/// N2 - Little is understood about connectivity of deep-sea fish populations. Analysis of the geochemical properties of fish otoliths is one way to draw inferences regarding their movements and habitat use in the marine environment. Trace element and stable isotope analyses of otoliths were undertaken to assess patterns of spatial and temporal population structure of a wide-ranging deepwater fish, the roundnose grenadier Coryphaenoides rupestris. Fish were sampled from 4 locations across the distribution range of the species in the northeast Atlantic. Multivariate analyses of elemental ratios (Li/Ca, Mn/Ca, Ba/Ca, Zn/Ca, Cu/Ca) revealed strong geographic separation at each life stage, and an overall significant difference between life stages. Otolith oxygen (?18O) and carbon (?13C) stable isotope analysis indicated a depth migration (and reduction in metabolic activity) from relatively shallow in the juvenile phase to much deeper in the adult phase at all locations. The results suggest that roundnose grenadier are comprised of geographically distinct population units that persist throughout their life-history, migrating deeper as they get older. JF - Marine Ecology Progress Series VL - 435 KW - Roundnose grenadier KW - North Atlantic KW - Otolith microchemistry KW - Stable isotopes KW - Population connectivity KW - Laser ablation ICP-MS TI - Otolith geochemistry indicates life-long spatial population structuring in a deep-sea fish, Coryphaenoides rupestris SP - 209 AV - none EP - 224 ER - TY - JOUR ID - soton174277 UR - https://eprints.soton.ac.uk/174277/ IS - 3-4 A1 - Longmore, Craig A1 - Fogarty, Kate A1 - Neat, Francis A1 - Brophy, Deirdre A1 - Trueman, Clive A1 - Milton, Andrew A1 - Mariani, Stefano Y1 - 2010/// N2 - The study of the morphological and chemical characteristics of otoliths have recently been proposed as complementary tools for fish stock identification. However, their effectiveness remains to be fully assessed, especially in species whose life history is still poorly understood. The relative efficiency of otolith microchemistry and otolith shape analysis in discriminating samples of the deep-sea macrourid Coryphaenoides rupestris collected in different areas in the North Atlantic was examined. Otolith microchemistry based on LA/ICP-MS found significant differences in the concentrations of lithium, manganese
and barium among sample sites. This allowed for very high classification accuracy (92%), when using discriminant function analysis. Otolith shape analysis based both on linear shape measurements and elliptical Fourier analysis revealed a contrasting weak discrimination, with only 43% classification success. Otolith microchemistry appears to be a more effective tool in identifying individual fish from different locations. The implications for the study of population structure are discussed taking into account the limitations of the methodologies employed. JF - Environmental Biology of Fishes VL - 89 KW - Roundnose Grenadier KW - ICP-MS KW - Stock structure KW - Trace elements KW - Elliptic Fourier Analysis KW - North Atlantic KW - Fisheries management SN - 0378-1909 TI - A comparison of otolith microchemistry and otolith shape analysis for the study of spatial variation in a deep-sea teleost, Coryphaenoides rupestris SP - 591 AV - none EP - 605 ER - TY - JOUR ID - soton194427 UR - https://eprints.soton.ac.uk/194427/ IS - 17-18 A1 - Longworth, Hannah R. A1 - Bryden, Harry L. A1 - Baringer, Molly O. Y1 - 2011/09// N2 - The strength of the Atlantic Meridional Overturning Circulation (MOC) at 26.5°N may be inferred from the combination of Florida Straits transport (derived from cable measurements), Ekman transport estimated from wind stress climatologies and mid-ocean geostrophic shear (traditionally obtained from hydrographic sections) with application of mass balance to the section to yield the mid-ocean barotropic flow. The recent Rapid monitoring project has provided time series information for the mid-ocean geostrophic shear since 2004. This work presents methods to assemble a comparable dataset from CTD end stations and boundary mooring temperature and pressure time series to estimate the past variability from 1980 to 2005. Variability in the end station derived transport anomalies suggests that the MOC has fluctuated by more than 10 Sv, encompassing all MOC estimates reported in the literature. Interannual changes in MOC transport are masked by this variability and calculated trends in layer transports are not statistically significant. More extensive datasets of CTD casts and moored temperature records at the western boundary do show significant changes with warming in the thermocline and long-term freshening of the deep waters between the 1980s and 2005. These changes are associated with stronger southward flow in the upper waters and weaker southward flow in the deep waters, and suggest a decrease in the MOC strength of 2?4 Sv. Any such decrease, however, is masked by the scale of variability in layer transports derived from the historical database of CTD end stations. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 58 KW - Atlantic circulation KW - Meridional overturning circulation KW - Climate change KW - Thermocline recirculation KW - Deep western boundary current SN - 0967-0645 TI - Historical variability in Atlantic meridional baroclinic transport at 26.5°N from boundary dynamic height observations SP - 1754 AV - none EP - 1767 ER - TY - JOUR ID - soton350084 UR - https://eprints.soton.ac.uk/350084/ IS - 12 A1 - Lázár, Attila N. A1 - Butterfield, Dan A1 - Futter, Martyn N. A1 - Rankinen, Katri A1 - Thouvenot-Korppoo, Marie A1 - Jarritt, Nick A1 - Lawrence, Deborah S.L. A1 - Wade, Andrew J. A1 - Whitehead, Paul G. Y1 - 2010/05// N2 - There is a need for better links between hydrology and ecology, specifically between landscapes and riverscapes to understand how processes and factors controlling the transport and storage of environmental pollution have affected or will affect the freshwater biota. Here we show how the INCA modelling framework, specifically INCA-Sed (the Integrated Catchments model for Sediments) can be used to link sediment delivery from the landscape to sediment changes in-stream. INCA-Sed is a dynamic, process-based, daily time step model. The first complete description of the equations used in the INCA-Sed software (version 1.9.11) is presented. This is followed by an application of INCA-Sed made to the River Lugg (1077 km2) in Wales. Excess suspended sediment can negatively affect salmonid health. The Lugg has a large and potentially threatened population of both Atlantic salmon (Salmo salar) and Brown Trout (Salmo trutta). With the exception of the extreme sediment transport processes, the model satisfactorily simulated both the hydrology and the sediment dynamics in the catchment. Model results indicate that diffuse soil loss is the most important sediment generation process in the catchment. In the River Lugg, the mean annual Guideline Standard for suspended sediment concentration, proposed by UKTAG, of 25 mg l? 1 is only slightly exceeded during the simulation period (1995?2000), indicating only minimal effect on the Atlantic salmon population. However, the daily time step simulation of INCA-Sed also allows the investigation of the critical spawning period. It shows that the sediment may have a significant negative effect on the fish population in years with high sediment runoff. It is proposed that the fine settled particles probably do not affect the salmonid egg incubation process, though suspended particles may damage the gills of fish and make the area unfavourable for spawning if the conditions do not improve. JF - Science of the Total Environment VL - 408 KW - sediment KW - INCA KW - semi-distributed KW - process-based model KW - lugg KW - atlantic salmon KW - salmo salar SN - 0048-9697 TI - An assessment of the fine sediment dynamics in an upland river system: INCA-Sed modifications and implications for fisheries SP - 2555 AV - none EP - 2566 ER - TY - JOUR ID - soton340712 UR - https://eprints.soton.ac.uk/340712/ IS - 9 A1 - MacKenzie, Kirsteen M. A1 - Trueman, Clive N. A1 - Palmer, Martin R. A1 - Moore, Andy A1 - Ibbotson, Anton T. A1 - Beaumont, William R.C. A1 - Davidson, Ian C. Y1 - 2012/// N2 - Locating and differentiating the marine feeding areas used by adult salmon (Salmo salar) is essential to stock-based management and conservation, but traditional tagging studies are limited and influenced by the uneven distribution of the fisheries or research vessel surveys. Here, a novel approach is used, based on the observation that the isotopic composition of animal tissues is intrinsically linked to the environmental conditions during tissue growth, which allows for the distinction of pelagic fish feeding in different locations. This isotopic approach is applied using archived collections of salmon scales and shows that (i) salmon act as size-structured pelagic predators, (ii) adult salmon from different natal origins within the UK (and hence components of the southern European stock complex) feed in different oceanic regions before their return, (iii) one-sea-winter (1SW) and multi-sea-winter salmon returning to some rivers in the UK are separated in their marine feeding areas, whereas those from others are not, and (iv) salmon from the rivers sampled are not feeding in regions of the Northwest Atlantic used by 1SW salmon returning to rivers in Newfoundland. Therefore, the stable isotope approach allows for retrospective investigations of marine diet, location, and migration at stock- and cohort-specific levels. JF - ICES Journal of Marine Science VL - 69 KW - microchemistry KW - migration KW - North Atlantic KW - Salmo salar KW - scales SN - 1054-3139 TI - Stable isotopes reveal age-dependent trophic level and spatial segregation during adult marine feeding in populations of salmon SP - 1637 AV - none EP - 1645 ER - TY - JOUR ID - soton69526 UR - https://eprints.soton.ac.uk/69526/ IS - 3-4 A1 - MacLeod, C.J. A1 - Searle, R.C. A1 - Murton, B.J. A1 - Casey, J.F. A1 - Mallows, C. A1 - Unsworth, S.C. A1 - Achenbach, K.L. A1 - Harris, M. Y1 - 2009/10/15/ N2 - Oceanic core complexes are the uplifted footwalls of very-large-offset low-angle normal faults that exhume lower crust and mantle rocks onto the seafloor at slow-spreading ridges. Although it is suggested on the basis of numerical modelling that they form during periods of relatively reduced magma supply, little is known about how they initiate and become inactive, nor why only certain normal fault systems develop into core complexes. In this paper we present results from a near-bottom sidescan sonar/bathymetric profiler survey and sampling study of the Mid-Atlantic Ridge near 13°N that identify the critical controls on oceanic core complex development and evolution. We show that core complex detachment faults initiate as high-angle (65° ± 10°) normal faults no different from surrounding valley-wall faults and, like them, rapidly flatten to dips of 30° in response to flexural unloading; however, on certain structures slip continues rather than being relayed inward onto a new normal fault. Runaway displacement appears to be triggered primarily by local waning of magma supply below a critical threshold, then aided by strain localisation resulting from seawater penetration and talc formation along the fault zones. Spreading becomes markedly asymmetric when the core complexes are active, and volcanism is suppressed or absent. When the asymmetry is such that the detachments accommodate more than half the total plate separation the active faults migrate across the axial valley. As a consequence magma is emplaced into and captured by the footwall of the detachment fault rather than being injected into the hanging wall, explaining the frequent presence of gabbro bodies and other melt relicts at oceanic core complexes. Core complexes are ultimately terminated when sufficient magma is emplaced to overwhelm the detachment fault; in the 13°N area by neovolcanic ridges propagating laterally across them from magmatically robust segments along strike.

JF - Earth and Planetary Science Letters VL - 287 KW - oceanic core complex KW - detachment fault KW - Mid-Atlantic Ridge KW - seafloor spreading KW - mantle exhumation KW - melt emplacement KW - mantle lithosphere KW - footwall capture SN - 0012-821X TI - Life cycle of oceanic core complexes SP - 333 AV - none EP - 344 ER - TY - JOUR ID - soton74704 UR - https://eprints.soton.ac.uk/74704/ IS - 8 A1 - Mackay, Edward B.L. A1 - Bahaj, AbuBakr S. A1 - Challenor, Peter G. Y1 - 2010/08// N2 - The uncertainty in estimates of the energy yield from a wave energy converter (WEC) is considered. The study is presented in two articles. The first article considered the accuracy of the historic data and the second article, presented here, considers the uncertainty which arises from variability in the wave climate. Mean wave conditions exhibit high levels of interannual variability. Moreover, many previous studies have demonstrated longer-term decadal changes in wave climate. The effect of interannual and climatic changes in wave climate on the predictability of long-term mean WEC power is examined for an area off the north coast of Scotland. In this location anomalies in mean WEC power are strongly correlated with the North Atlantic Oscillation (NAO) index. This link enables the results of many previous studies on the variability of the NAO and its sensitivity to climate change to be applied to WEC power levels. It is shown that the variability in 5, 10 and 20 year mean power levels is greater than if annual power anomalies were uncorrelated noise. It is also shown that the change in wave climate from anthropogenic climate change over the life time of a wave farm is likely to be small in comparison to the natural level of variability. Finally, it is shown that despite the uncertainty related to variability in the wave climate, improvements in the accuracy of historic data will improve the accuracy of predictions of future WEC yield. JF - Renewable Energy VL - 35 KW - wave energy resource KW - variability KW - stochastic model KW - north atlantic oscillation KW - climate change KW - uncertainty SN - 0960-1481 TI - Uncertainty in wave energy resource assessment part 2: variability and predictability SP - 1809 AV - none EP - 1819 ER - TY - JOUR N1 - This article has a correction. Please see: https://doi.org/10.1016/j.pocean.2020.102390 ID - soton437910 UR - https://eprints.soton.ac.uk/437910/ A1 - Macovei, Vlad A. A1 - Hartman, Susan E. A1 - Schuster, Ute A1 - Torres-Valdés, Sinhué A1 - Moore, C. Mark A1 - Sanders, Richard J. Y1 - 2020/01/01/ N2 - The ocean is currently a significant net sink for anthropogenically remobilised CO2, taking up around 24% of global emissions. Numerical models predict a diversity of responses of the ocean carbon sink to increased atmospheric concentrations in a warmer world. Here, we tested the hypothesis that increased atmospheric forcing is causing a change in the ocean carbon sink using a high frequency observational dataset derived from underway pCO2 (carbon dioxide partial pressure) instruments on ships of opportunity (SOO) and a fixed-point mooring between 2002 and 2016. We calculated an average carbon flux of 0.013 Pg yr?1 into the ocean at the Porcupine Abyssal Plain (PAP) site, consistent with past estimates. In spite of the increase in atmospheric pCO2, monthly average seawater pCO2 did not show a statistically significant increasing trend, but a higher annual variability, likely due to the decreasing buffer capacity of the system. The increasing





?pCO2
led to an increasing trend in the estimated CO2 flux into the ocean of 0.19 ± 0.03 mmol m?2 day?1 per year across the entire 15 year time series, making the study area a stronger carbon sink. Seawater pCO2 variability is mostly influenced by temperature, alkalinity and dissolved inorganic carbon (DIC) changes, with 77% of the annual seawater pCO2 changes explained by these terms. DIC is in turn influenced by gas exchange and biological production. In an average year, the DIC drawdown by biological production, as determined from nitrate uptake, was higher than the DIC increase due to atmospheric CO2 dissolution into the surface ocean. This effect was enhanced in years with high nutrient input or shallow mixed layers. Using the rate of change of DIC and nitrate, we observed Redfieldian carbon consumption during the spring bloom at a C:N ratio of 6.2 ± 1.6. A comparison between SOO and PAP sustained observatory data revealed a strong agreement for pCO2 and DIC. This work demonstrates that the study area has continued to absorb atmospheric CO2 in recent years with this sink enhancing over time. Furthermore, the change in pCO2 per unit nitrate became larger as surface buffer capacity changed. JF - Progress in Oceanography VL - 180 KW - Biological production KW - CO flux KW - North Atlantic KW - pCO variability SN - 0079-6611 TI - Impact of physical and biological processes on temporal variations of the ocean carbon sink in the mid-latitude North Atlantic (2002?2016) SP - 1 AV - public EP - 14 ER - TY - JOUR ID - soton2097 UR - http://www.int-res.com/abstracts/meps/v257/p1-11.html A1 - Maranon, E. A1 - Behrenfeld, M.J. A1 - Gonzalez, N. A1 - Mourino, B. A1 - Zubkov, M.V. Y1 - 2003/// N2 - The oligotrophic waters of the Subtropical Gyres cover >60% of the total ocean surface and contribute >30% of the global marine carbon fixation. Despite apparently uniform growth conditions over broad areas, primary production in these regions exhibits a remarkable degree of variability. In this study of 34 stations in the North and South Atlantic Subtropical Gyres, we found a 20 fold variation (from 18 to 362 mgC m-2 d-1) in water-column-integrated primary production rate (ÚPP), while chlorophyll biomass only varied by a factor of 3. The changes in productivity were not associated with variations in incident surface irradiance, chlorophyll concentration, phytoplankton C biomass or phytoplankton size structure. The rate of nutrient supply to the euphotic layer, as estimated from variations in the depth of nitracline, appeared as the most relevant environmental factor in explaining the observed variability in ÚPP. We found significant changes in the composition of the picophytoplankton community across the range of measured productivities. The relative biomass contribution of Synechococcus spp. and the picoeukaryotes tended to increase with increasing ÚPP, whereas the opposite was true for Prochlorococcus spp. Across the wide range of measured primary productivity rates, the persistent dominance of picophytoplankton indicates that the microbial loop and the microbial food web continued to be the most important trophic pathways. Our observations of the oligotrophic ocean reflect a dynamic ecosystem where the microbial community responds to environmental forcing with significant changes in biological rates rather than trophic organization. JF - Marine Ecology Progress Series VL - 257 KW - Primary production · Chlorophyll · Picoplankton · Size structure · Subtropical Gyres · Atlantic Ocean SN - 0171-8630 TI - High variability of primary production in oligotrophic waters of the Atlantic Ocean: uncoupling from phytoplankton biomass and size structure SP - 1 AV - none EP - 11 ER - TY - JOUR ID - soton7971 UR - http://www.int-res.com/articles/meps/216/m216p043.pdf A1 - Maranon, E. A1 - Holligan, P.M. A1 - Barciela, R. A1 - Gonzalez, N. A1 - Mourino, B. A1 - Pazo, M.J. A1 - Varela, M. Y1 - 2001/// N2 - A total of 94 vertical profiles of size-fractionated chlorophyll a concentration and primary production rate were obtained along a meridional transect from the United Kingdom to the Falkland Islands (50°N to 50°S) during 4 cruises carried out in April and October 1996 and in April and October 1997. This data set allowed us to characterize the patterns of phytoplankton size-structure and productivity in temperate, oligotrophic, upwelling and equatorial regions. On average, picophytoplankton (0.2 to 2 µm) accounted for 56 and 71% of the total integrated carbon (C) fixation and autotrophic biomass, respectively. Enhanced biomass and productivity contributions by nano- and microplankton took place in the temperate regions and in the upwelling area off Mauritania. Small (<2 µm in diameter) phytoplankton cells should not be regarded as a background, relatively invariant component of the microbial community, given that most of the latitudinal variability in total photoautotrophic biomass and production was driven by changes in the picophytoplankton. In temperate regions and in the upwelling area off Mauritania, small (<2 µm) and large (>2 µm) phytoplankton accounted for a proportion of total biomass that was similar to their shares of productivity. In the oligotrophic and equatorial regions, in contrast, large phytoplankton tended to account for a fraction of the total production that was significantly higher than their share of the biomass. We found that the equatorial upwelling causes an increase in phytoplankton biomass and productivity without altering the typical size structure found in less productive regions such as the subtropical gyres. In the oligotrophic ocean, significant changes in C fixation rates take place without accompanying variations in the magnitude of the phytoplankton standing stocks or the size structure of the microbial community. JF - Marine Ecology Progress Series VL - 216 KW - PHYTOPLANKTON KW - SIZE KW - BIOMASS KW - ASSEMBLAGES KW - PRIMARY PRODUCTION KW - CHLOROPHYLL KW - FOOD WEBS KW - PLANKTON KW - ATLANTIC OCEAN TI - Patterns of phytoplankton size structure and productivity in contrasting open-ocean environments SP - 43 AV - none EP - 56 ER - TY - JOUR ID - soton8707 UR - https://eprints.soton.ac.uk/8707/ IS - 5 A1 - Maranon, E. A1 - Holligan, P.M. A1 - Varela, M. A1 - Mourino, B. A1 - Bale, A.J. Y1 - 2000/// N2 - The latitudinal distributions of phytoplankton biomass, composition and production in the Atlantic Ocean were determined along a 10,000-km transect from 50°N to 50°S in October 1995, May 1996 and October 1996. Highest levels of euphotic layer-integrated chlorophyll a (Chl a) concentration (75?125 mg Chl m?2) were found in North Atlantic temperate waters and in the upwelling region off NW Africa, whereas typical Chl a concentrations in oligotrophic waters ranged from 20 to 40 mg Chl m?2. The estimated concentration of surface phytoplankton carbon (C) biomass was 5?15 mg C m?2 in the oligotrophic regions and increased over 40 mg C m?2 in richer areas. The deep chlorophyll maximum did not seem to constitute a biomass or productivity maximum, but resulted mainly from an increase in the Chl a to C ratio and represented a relatively small contribution to total integrated productivity. Primary production rates varied from 50 mg C m?2 d?1 at the central gyres to 500?1000 mg C m?2 d?1 in upwelling and higher latitude regions, where faster growth rates () of phytoplankton (>0.5 d?1) were also measured. In oligotrophic waters, microalgal growth was consistently slow [surface averaged 0.21±0.02 d?1 (mean±SE)], representing <20% of maximum expected growth. These results argue against the view that the subtropical gyres are characterized by high phytoplankton turnover rates. The latitudinal variations in were inversely correlated to the changes in the depth of the nitracline and positively correlated to those of the integrated nitrate concentration, supporting the case for the role of nutrients in controlling the large-scale distribution of phytoplankton growth rates. We observed a large degree of temporal variability in the phytoplankton dynamics in the oligotrophic regions: productivity and growth rates varied in excess of 8-fold, whereas microalgal biomass remained relatively constant. The observed spatial and temporal variability in the biomass specific rate of photosynthesis is at least three times larger than currently assumed in most satellite-based models of global productivity. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 47 KW - PHYTOPLANKTON KW - BIOMASS KW - BIOLOGICAL PRODUCTION KW - ATLANTIC OCEAN KW - GROWTH KW - CHLOROPHYLL KW - "JAMES CLARK ROSS" KW - LATITUDINAL VARIATIONS SN - 0967-0637 TI - Basin-scale variability of phytoplankton biomass, production and growth in the Atlantic Ocean SP - 825 AV - none EP - 857 ER - TY - JOUR ID - soton49763 UR - http://www.int-res.com/articles/ame2007/48/a048p261.pdf IS - 3 A1 - Maranon, E. A1 - Perez, V. A1 - Fernandez, E. A1 - Anadon, R. A1 - Bode, A. A1 - Gonzalez, N. A1 - Huskin, I. A1 - Isla, A. A1 - Moran, X.A.G. A1 - Mourino, B. A1 - Quevedo, M. A1 - Robinson, C. A1 - Serret, P. A1 - Teiral, E. A1 - Varela, M.M. A1 - Woodward, E.M.S. A1 - Zubkov, M.V. Y1 - 2007/08/12/ N2 - We used data collected at >60 stations over a 10 yr period to build the carbon budget of the plankton community in the euphotic layer of the Eastern North Atlantic Subtropical Gyre (NASE). Autotrophic biomass exceeded microbial heterotrophic biomass by a factor of 1.7. Mean (±SE), integrated chlorophyll a concentration and net particulate primary production (PP) were 17 ± 1 mg m?2 and 271 ± 29 mgC m?2 d?1, respectively. Protist grazing on phytoplankton represented >90% of PP. Bacterial production (BP) was 17 ± 3 mgC m?2 d?1. In vitro O2-evolution experiments indicated that net community production was ?65 ± 16 mmolO2 m?2 d?1, while community respiration (CR) averaged 124 ± 13 mmolO2 m?2 d?1, equivalent to 1324 ± 142 mgC m?2 d?1. However, the sum of the respiration rates by each microbial group, estimated from their biomass and metabolic rates, ranged from 402 to 848 mgC m?2 d?1. Therefore, CR could not be reconciled with the respiratory fluxes sustained by each microbial group. Comparison between estimated gross photosynthesis by phytoplankton (481 to 616 mgC m?2 d?1) and the sum of respiration by each group suggests that the microbial community in the NASE province is close to metabolic balance, which would agree with the observed O2 supersaturation in the euphotic layer. Taking into account the mean open-ocean values for PP, BP, CR and bacterial growth efficiency, we show that bacteria account for approximately 20% of CR. Our results suggest that the view that bacteria dominate carbon cycling in the unproductive ocean must be reconsidered, or else that in vitro incubations misrepresent the real metabolic rates of one or several microbial groups. JF - Aquatic Microbial Ecology VL - 48 KW - Plankton KW - Primary production KW - Bacterial production KW - Respiration KW - Grazing KW - Subtropical NE Atlantic KW - Atlantic Meridional Transect SN - 0948-3055 TI - Planktonic carbon budget in the eastern subtropical North Atlantic SP - 261 AV - none EP - 275 ER - TY - JOUR ID - soton5965 UR - https://eprints.soton.ac.uk/5965/ IS - 47, Supplement A1 - Marotzke, J. Y1 - 2001/// JF - EOS: Transactions American Geophysical Union VL - 82 KW - THERMOHALINE CIRCULATION KW - NORTH ATLANTIC OCEAN KW - ATLN KW - VARIABILITY SN - 0096-3941 TI - Abrupt climate change and the thermohaline circulation: concepts and observations AV - none ER - TY - JOUR ID - soton44195 UR - http://www.metapress.com/content/58x1867km1333637/fulltext.html IS - 1 A1 - Marques, A.F.A. A1 - Barriga, F. A1 - Chavagnac, V. A1 - Fouquet, Y. Y1 - 2006/// N2 - Petrological, geochemical, and Nd isotopic analyses have been carried out on rock samples from the Rainbow vent field to assess the evolution of the hydrothermal system. The Rainbow vent field is an ultramafic-hosted hydrothermal system located on the Mid-Atlantic Ridge characterized by vigorous high-temperature venting (?365°C) and unique chemical composition of fluids: high chlorinity, low pH and very high Fe, and rare earth element (REE) contents (Douville et al., Chemical Geology 184:37?48, 2002). Serpentinization has occurred under a low-temperature (<270°C) retrograde regime, later overprinted by a higher temperature sulfide mineralization event. Retrograde serpentinization reactions alone cannot reproduce the reported heat and specific chemical features of Rainbow hydrothermal fluids. The following units were identified within the deposit: (1) nonmineralized serpentinite, (2) mineralized serpentinite?stockwork, (3) steatite, (4) semimassive sulfides, and (5) massive sulfides, which include Cu-rich massive sulfides (up to 28wt% Cu) and Zn-rich massive sulfide chimneys (up to 5wt% Zn). Sulfide mineralization has produced significant changes in the sulfide-bearing rocks including enrichment in transition metals (Cu, Zn, Fe, and Co) and light REE, increase in the Co/Ni ratios comparable to those of mafic Cu-rich volcanic-hosted massive sulfide deposits and different 143Nd/144Nd isotope ratios. Vent fluid chemistry data are indicative of acidic, reducing, and high temperature conditions at the subseafloor reaction zone where fluids undergo phase separation most likely under subcritical conditions (boiling). An explanation for the high chlorinity is not straightforward unless mixing with high salinity brine or direct contribution from a magmatic Cl-rich aqueous fluid is considered. This study adds new data, which, combined with the current knowledge of the Rainbow vent field, brings compelling evidence for the presence, at depth, of a magmatic body, most likely gabbroic, which provides heat and metals to the system. Co/Ni ratios proved to be good tools used to discriminate between rock units, degree of sulfide mineralization, and positioning within the hydrothermal system. Deeper units have Co/Ni <1 and subsurface and surface units have Co/Ni >1. JF - Mineralium Deposita VL - 41 KW - massive sulfides KW - serpentinite KW - Nd isotopes KW - Mid-Atlantic Ridge KW - Rainbow vent field SN - 0026-4598 TI - Mineralogy, geochemistry, and Nd isotope composition of the Rainbow hydrothermal field, Mid-Atlantic Ridge SP - 52 AV - none EP - 67 ER - TY - JOUR ID - soton8868 UR - https://eprints.soton.ac.uk/8868/ IS - 2 A1 - Marsh, R. Y1 - 2000/// JF - Atmosphere-Ocean VL - 38 KW - NORTH ATLANTIC OCEAN KW - NAO KW - NORTH ATLANTIC OSCILLATION KW - CLIMATIC CHANGE EFFECTS KW - WINDS KW - ATMOSPHERIC FORCING KW - OCEAN MODELS KW - NORTHWEST ATLANTIC OCEAN TI - Modelling changes in North Atlantic circulation under the NAO-Minimum Wind Forcing of 1877-81 SP - 367 AV - none EP - 393 ER - TY - JOUR ID - soton8012 UR - https://eprints.soton.ac.uk/8012/ IS - 1 A1 - Marsh, R. A1 - Megann, A.P. Y1 - 2002/// N2 - Offline particle trajectories are obtained for a quasi-global isopycnic-coordinate OGCM using an analytical method, adapted for use with online time-integrated isopycnal and diapycnal mass fluxes. The method is highly efficient, allowing the calculation of large ensembles of such trajectories. These ensembles can be used to establish pathways and transformations associated with the global circulation of water masses on timescales which are well in excess of any feasible model integration length. The method is here used to investigate the important, yet poorly observed, transformation of North Atlantic Deep Water (NADW) through slow spreading, upwelling and diapycnal mixing (defined when and where density decreases below a threshold value). A fundamental problem arises through unsteadiness in the thickness of NADW layers (due to various model flaws and/or intrinsic variability). Particles converge on gridboxes where layers inflate during the online time-integration period. Depending on the degree of layer inflation, only a fraction of NADW particles can be diagnosed as transformed at some point along their respective trajectories. However, the unsteadiness of layer thickness decreases during a 50-year spin-up, implying fewer converged trajectories and an increased fraction of transformed NADW. Using trajectories to trace NADW southward across the equatorial Atlantic, with mass fluxes from years 10, 30 and 50 of model spin-up, the transformed percentage (of NADW exported from the North Atlantic) increases from 17?18% (with fluxes from years 10 and 30) to 41% (using year 50 fluxes). In the latter case, about 30% of the NADW upwells south of 30°S after 500?1000 years. Most of the remaining 70% upwells in the South and North Pacific after 1000?2500 years. JF - Ocean Modelling VL - 4 KW - WOCE KW - OCEAN MODEL KW - NORTH ATLANTIC DEEP WATER KW - CONVEYOR BELT KW - ISOPYCNALS KW - DIAPYCNALS SN - 1463-5003 TI - Tracing water masses with particle trajectories in an isopycnic-coordinate model of the global ocean SP - 27 AV - none EP - 53 ER - TY - JOUR ID - soton2181 UR - https://eprints.soton.ac.uk/2181/ IS - 24 A1 - Martin, A.P. A1 - Srokosz, M.A. Y1 - 2002/// JF - Geophysical Research Letters VL - 29 KW - PLANKTON KW - PHYTOPLANKTON KW - ATLANTIC OCEAN KW - CHLOROPHYLL KW - GEOGRAPHICAL DISTRIBUTION KW - HORIZONTAL DISTRIBUTION KW - BIOLOGY SN - 0094-8276 TI - Plankton distribution spectra: inter-size class variability and the relative slopes for phytoplankton and zooplankton AV - none ER - TY - JOUR ID - soton177839 UR - https://eprints.soton.ac.uk/177839/ IS - 4 A1 - Martin, Patrick A1 - Lampitt, Richard S. A1 - Perry, Mary Jane A1 - Sanders, Richard A1 - Lee, Craig A1 - D'Asaro, Eric Y1 - 2011/04// N2 - Spring diatom blooms are important for sequestering atmospheric CO2 below the permanent thermocline in the form of particulate organic carbon (POC). We measured downward POC flux during a sub-polar North Atlantic spring bloom at 100 m using thorium-234 (234Th) disequilibria, and below 100 m using neutrally buoyant drifting sediment traps. The cruise followed a Lagrangian float, and a pronounced diatom bloom occurred in a 600 km2 area around the float. Particle flux was low during the first three weeks of the bloom, between 10 and 30 mg POC m?2 d?1. Then, nearly 20 days after the bloom had started, export as diagnosed from 234Th rose to 360?620 mg POC m?2 d?1, co-incident with silicate depletion in the surface mixed layer. Sediment traps at 600 and 750 m depth collected 160 and 150 mg POC m?2 d?1, with a settled volume of particles of 1000?1500 mL m?2 d?1. This implies that 25?43% of the 100 m POC export sank below 750 m. The sinking particles were ungrazed diatom aggregates that contained transparent exopolymer particles (TEP). We conclude that diatom blooms can lead to substantial particle export that is transferred efficiently through the mesopelagic. We also present an improved method of calibrating the Alcian Blue solution against Gum Xanthan for TEP measurements. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 58 KW - Neutrally buoyant sediment traps KW - Thorium-234 KW - Particulate organic carbon flux KW - North Atlantic spring bloom KW - Transparent exopolymer particles SN - 0967-0637 TI - Export and mesopelagic particle flux during a North Atlantic spring diatom bloom SP - 338 AV - none EP - 349 ER - TY - JOUR ID - soton379761 UR - https://eprints.soton.ac.uk/379761/ IS - 3 A1 - Martínez-Asensio, Adrián A1 - Tsimplis, Michael N. A1 - Marcos, Marta A1 - Feng, Xiangbo A1 - Gomis, Damià A1 - Jordà, Gabriel A1 - Josey, Simon A. Y1 - 2016/03// N2 - This study investigates the relationship between the wind wave climate and the main climate modes of atmospheric variability in the North Atlantic Ocean. The modes considered are the North Atlantic Oscillation (NAO), the East Atlantic (EA) pattern, the East Atlantic Western Russian (EA/WR) pattern and the Scandinavian (SCAN) pattern. The wave dataset consists of buoys records, remote sensing altimetry observations and a numerical hindcast providing significant wave height (SWH), mean wave period (MWP) and mean wave direction (MWD) for the period 1989?2009. After evaluating the reliability of the hindcast, we focus on the impact of each mode on seasonal wave parameters and on the relative importance of wind-sea and swell components. Results demonstrate that the NAO and EA patterns are the most relevant, whereas EA/WR and SCAN patterns have a weaker impact on the North Atlantic wave climate variability. During their positive phases, both NAO and EA patterns are related to winter SWH at a rate that reaches 1?m per unit index along the Scottish coast (NAO) and Iberian coast (EA) patterns. In terms of winter MWD, the two modes induce a counterclockwise shift of up to 65° per negative NAO (positive EA) unit over west European coasts. They also increase the winter MWP in the North Sea and in the Bay of Biscay (up to 1?s per unit NAO) and along the western coasts of Europe and North Africa (1?s per unit EA). The impact of winter EA pattern on all wave parameters is mostly caused through the swell wave component. JF - International Journal of Climatology VL - 36 KW - climate indices KW - east atlantic (EA) pattern KW - inter-annual variability KW - north atlantic KW - north atlantic oscillation (NAO) KW - wave climate TI - Response of the North Atlantic wave climate to atmospheric modes of variability SP - 1210 AV - none EP - 1225 ER - TY - JOUR ID - soton43952 UR - http://www.int-res.com/articles/ame2006/45/a045p107.pdf IS - 2 A1 - Mary, I. A1 - Heywood, J.L. A1 - Fuchs, B.M. A1 - Amann, R. A1 - Tarran, G.A. A1 - Burkill, P.H. A1 - Zubkov, M.V. Y1 - 2006/// N2 - Low nucleic acid (LNA) bacterioplankton (sorted by flow cytometry) were characterised in surface water samples along a meridional transect from 48°N to 40° S across the Atlantic Ocean. The LNA bacterioplankton abundance and metabolic activity, assessed by their 35S-methionine uptake rate, were similar along the transect, representing 36 ± 6 and 36 ± 11% of total bacterioplankton, respectively. Fluorescence in situ hybridisation analysis of the flow-sorted cells revealed that the LNA bacterioplankton population was dominated (59 ± 4%) by and contained virtually all the identifiable SAR11 clade cells throughout the Atlantic Ocean. Therefore, the present study provides ecological characterisation of this flow-sorted group and suggests both phylogenetic and functional constancy of the LNA bacterioplankton at the basin-scale. JF - Aquatic Microbial Ecology VL - 45 KW - flow cytometry sorting KW - cell metabolic activity KW - SAR11 clade KW - CARD-FISH KW - radioactive tracer labelling KW - Atlantic Ocean SN - 0948-3055 TI - SAR11 dominance among metabolically active low nucleic acid bacterioplankton in surface waters along an Atlantic Meridional Transect SP - 107 AV - none EP - 113 ER - TY - JOUR ID - soton371831 UR - https://eprints.soton.ac.uk/371831/ A1 - Marzocchi, Alice A1 - Hirschi, Joël J.-M. A1 - Holliday, N. Penny A1 - Cunningham, Stuart A. A1 - Blaker, Adam T. A1 - Coward, Andrew C. Y1 - 2015/02// N2 - The subpolar North Atlantic represents a key region for global climate, but most numerical models still have well-described limitations in correctly simulating the local circulation patterns. Here, we present the analysis of a 30-year run with a global eddy-resolving (1/12°) version of the NEMO ocean model. Compared to the 1° and 1/4° equivalent versions, this simulation more realistically represents the shape of the Subpolar Gyre, the position of the North Atlantic Current, and the Gulf Stream separation. Other key improvements are found in the representation of boundary currents, multi-year variability of temperature and depth of winter mixing in the Labrador Sea, and the transport of overflows at the Greenland?Scotland Ridge. However, the salinity, stratification and mean depth of winter mixing in the Labrador Sea, and the density and depth of overflow water south of the sill, still present challenges to the model. This simulation also provides further insight into the spatio-temporal development of the warming event observed in the Subpolar Gyre in the mid 1990s, which appears to coincide with a phase of increased eddy activity in the southernmost part of the gyre. This may have provided a gateway through which heat would have propagated into the gyre's interior. JF - Journal of Marine Systems VL - 142 KW - Ocean modelling KW - Eddy-resolving KW - NEMO KW - North Atlantic KW - Subpolar gyre warming KW - Physical oceanography SN - 0924-7963 TI - The North Atlantic subpolar circulation in an eddy-resolving global ocean model SP - 126 AV - public EP - 143 ER - TY - RPRT ID - soton315 UR - https://eprints.soton.ac.uk/315/ A1 - Masson, D.G. Y1 - 1997/// N2 - This was the first of two cruises, the overall objective of which was to undertake an integrated baseline environmental survey of the continental slope west of Shetland. The major objective of this cruise was to obtain TOBI (30 kHz) and 100 kHz sidescan sonar imagery of the designated survey area west of Shetland. All the objectives of the cruise were achieved in full or exceeded. Over 14000 km2 of seafloor was imaged with the TOBI system during 25 days of survey and 650 line km of 100 kHz data were obtained in 3.5 days of survey. Twelve sample stations were occupied during trials of the multicorer, box corer and Day grab. As anticipated, the mapped sediment facies variations are strongly related to waterdepth. Iceberg ploughmarks dominate the seafloor structure to depths of about 500 m. At mid slope depths, sediment bedforms and erosion due to current activity can be seen. At greater depths, less energetic depositional conditions prevail. Highlights of the sonar survey include the discovery of a field of barchan sand-dunes at a waterdepth of 300 m, a small sediment slide at 900-1000 m waterdepth, and an extensive sandy contourite sheet between the 850 and 1000 m depth contours between 61° and 61°20?N. The second cruise of the two cruises, mainly devoted to seabed sampling, is described in Southampton Oceanography Centre Cruise Report No. 7. PB - Southampton Oceanography Centre, University of Southampton T3 - 6 KW - AFEN KW - bedforms KW - Charles Darwin KW - continental slope KW - cruise 101C leg 1 1996 KW - environmental survey KW - Faeroe-Shetland Channel KW - NE Atlantic KW - ploughmarks KW - sediments KW - Shetland KW - sidescan sonar KW - sonar imagery KW - TOBI M1 - project_report TI - RRS Charles Darwin Cruise 101C Leg 1, 05 Jun-13 Jul 1996. TOBI surveys of the continental slope west of Shetland AV - public EP - 54 ER - TY - RPRT ID - soton8186 UR - https://eprints.soton.ac.uk/8186/ A1 - Masson, D.G. A1 - Jacobs, C.L. Y1 - 1999/// N2 - The objective of the cruise was to undertake comprehensive TOBI 30 kHz sidescan sonar and 7.5 kHz profiler surveys of several blocks of seafloor to the north and west of the UK which were released for hydrocarbon exploration in 1997 (Fig. 1). All of the license areas with water depth >200 m was to be surveyed. Surface towed 3.5 kHz high resolution profiles were also to be collected along all survey lines. The Research Vessel Colonel Templer was chartered by Geotek Ltd. to undertake the survey work. Although TOBI has a nominal swath width of 6 km, survey lines were typically spaced 4 to 5 km apart to allow for overlap between adjacent swaths, and for some reduction in range in the shallower water areas (typically < 1000 m waterdepth) in the northern survey blocks. This range reduction occurs because of severe temperature stratification in the water column, where warm North Atlantic Water (typically 8-9°C) immediately overlies cold water originating in the Norwegian Sea (typically < 0°C), causing refraction and reflection of the sonar energy.

Processing of data and interpretation of results It was planned that a preliminary interpretation of the data would be undertaken during the survey, so that results could be transmitted to a related sampling cruise being carried out on the RRS Charles Darwin. This sampling cruise partly overlapped the sidescan surveys in time, necessitating a rapid turn round in data processing and interpretation. To this end, preliminary image processing was carried out on board, producing sidescan mosaics at a scale of 1:50,000. Sidescan and profile data were then combined into an integrated interpretation which was transmitted in digital form either to Geotek Ltd. or directly to the RRS Charles Darwin.Data annotation All data were recorded with reference to GMT and Julian day numbers.

This report was originally issued as part of the AFEN 17th Round Atlantic Margins Environmental Survey data CD-ROM. PB - Southampton Oceanography Centre, University of Southampton T3 - 22 KW - acronym KW - AFEN KW - Atlantic Frontier Environmental Network KW - Atlantic Margins Environmental Survey KW - Colonel Templar KW - cruise 01 1998 KW - cruise 02 1998 KW - TOBI M1 - project_report TI - RV Colonel Templer Cruises 01 & 02/98, 22 Apr-18 Jun 1998. TOBI surveys of the continental slope north and west of Scotland AV - public EP - 66 ER - TY - JOUR ID - soton170213 UR - https://eprints.soton.ac.uk/170213/ IS - 1-4 A1 - Mawji, Edward A1 - Gledhill, M. A1 - Milton, J.A. A1 - Zubkov, M.V. A1 - Thompson, Anu A1 - Wolff, George A. A1 - Achterberg, Eric P. Y1 - 2011/03/20/ N2 - Siderophore type chelates were detected in nutrient enriched, incubated seawater collected from different biogeographical regions of the Atlantic Ocean. Seawater was enriched with glucose and ammonium, glycine (as a source of carbon and nitrogen) or chitin and ammonium at different concentrations and incubated for up to 3 ? 4 days in the dark. Siderophore type chelates were detected using high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS) after complexation with Ga. Samples were subsequently analysed by HPLC - electrospray ionisation mass spectrometry (HPLC
ESI-MS) in order to confirm the identity of the known siderophores, and to obtain the pseudo molecular ions of unknown siderophore type chelates. A total of 22 different siderophore type chelates were resolved in the HPLC-ICP-MS chromatograms. Ten different siderophore type chelates were identified by HPLC-ESI-MS, 3 of which had not previously been identified in nutrient enriched seawater incubations. The concentration and diversity of siderophore typechelates was highest in seawater amended with glucose. The concentrations 1 and diversity of siderophore type chelates also varied with biogeographical area in the Atlantic Ocean, with the North Atlantic Sub-tropical Gyre yielding highest concentrations in incubations, and the South Atlantic Sub-tropical Gyre and Western Tropical Atlantic yielding the highest diversity. JF - Marine Chemistry VL - 124 KW - Iron biogeochemistry KW - Siderophores KW - Seawater KW - Bacteria KW - Atlantic Ocean SN - 0304-4203 TI - Production of siderophore type chelates in Atlantic Ocean waters enriched with different carbon and nitrogen sources SP - 90 AV - public EP - 99 ER - TY - THES ID - soton17240 UR - https://eprints.soton.ac.uk/17240/ A1 - Mayor, D.J. Y1 - 2005/03// N2 - Ship-board experiments in the North Atlantic were used to study how food quality influences the egg production of Calanus finmarchicus feeding on natural planktonic diets. Food quality was expressed in terms of carbon (C), nitrogen (N), and the essential fatty acids eicosapentaenoic acid (EPA; 20:5(n-3)) and docosahexaenoic acid (DHA; 22:6(n-3)). Five consecutive 24 hr bottle incubations were conducted in April and July/August 2002 under in situ conditions to determine egg production rates and the ingested quantities of C, N, EPA and DHA. Biomass contributions towards growth were determined and the biochemical composition of the eggs was examined. In order to accurately determine ingestion rates, a method to account for microzooplankton grazing in particle removal experiments was developed.
Balanced physiological budgets were compiled for C. finmarchicus in both seasons. The input terms of these budgets consisted of ingestion and the use of biomass, and the outputs were growth, respiration, excretion and egestion. Respiration and excretion were not determined experimentally, and were therefore determined by mass balance and compared to literature-derived values.
In April, close agreement between literature- and mass balance-derived rates of respiration and excretion demonstrated that the experimentally determined components of the budget were accurate. Ingestion rates were low, and > 80 % of the C utilised was derived internally from somatic biomass. The absence of storage fatty acids and the low C:N ratio (~ 4 µg µg-1) of the biomass lost from the females indicated that these animals had been catabolising structural protein and were close to exhaustion. This suggests that when food is scarce, C. finmarchicus adopts a semelparous reproductive strategy. In July/August, the observed growth exceeded the estimated ingestion rates. This shortfall was possibly provided by cannibalising eggs.
Assuming that EPA and DHA were used with high efficiency (0.9), the stoichiometric analysis predicted that these compounds were non-limiting in April. Using typical maximum growth efficiencies for C (< 0.6) and N (0.4), the former was predicted to be limiting because the biomass utilised was rich in N, EPA and DHA relative to the demand for C. PB - University of Southampton KW - north atlantic ocean KW - feeding behaviour KW - diet M1 - phd TI - Nutritional regulation of egg production of Calanus Finmarchicus in the North Atlantic AV - public EP - 315 ER - TY - JOUR ID - soton385697 UR - https://eprints.soton.ac.uk/385697/ IS - 1 A1 - McAleer, John Y1 - 2016/01/01/ N2 - The British interest and presence in the South Atlantic Ocean and in South America represent, in the words of Eliga Gould, the kind of ?entangled histories? increasingly recognised and studied by scholars of imperial, colonial and maritime history. From the beginning of the eighteenth century, the region was most frequently seen as the ?key? to the Pacific Ocean. This paper, however, focuses on the place of this oceanic area, its islands and its coastal littorals in another ?gateway zone?: the entrance to, and exit from, Britain's Indian Ocean world and the riches of Asia. The strategic location of various South Atlantic islands and South American colonial entrepôts played on the minds of politicians, policy-makers, publicists and merchants in London, as well as colonial governors and military commanders on station. Drawing on the archival riches of the East India Company, as well as primary published material such as pamphlets and prospectuses, this paper will explore the interaction of the Atlantic and Indian oceans at this maritime fault-line. The discussion will demonstrate, for example, how the ?barren and rocky isle? of St Helena, ?abandoned to a state of hopeless destitution in the solitude of the ocean,? could be regarded as an ?essential part of the British Empire.? And similarly, it will demonstrate how places such as Montevideo, Rio de Janeiro and Tristan da Cunha were regarded in relation to the rising British Empire in Asia. More broadly, the region cannot be understood, this paper suggests, without considering the wider context of British imperial and commercial activity in the period and, more specifically, the growing importance of British trading and political interests in the East Indies. JF - Atlantic Studies VL - 13 KW - st helena KW - british empire KW - south atlantic KW - islands KW - indian ocean KW - east india company SN - 1478-8810 TI - Looking East: St Helena, the South Atlantic and Britain?s Indian Ocean world SP - 78 AV - restricted EP - 98 ER - TY - JOUR ID - soton342371 UR - https://eprints.soton.ac.uk/342371/ IS - 19 A1 - McCarthy, G. A1 - Frajka-Williams, E. A1 - Johns, W.E. A1 - Baringer, M.O. A1 - Meinen, C.S. A1 - Bryden, H.L. A1 - Rayner, D. A1 - Duchez, A. A1 - Roberts, C.D. A1 - Cunningham, S.A. Y1 - 2012/10// N2 - The Atlantic meridional overturning circulation (MOC) plays a critical role in the climate system and is responsible for much of the heat transported by the ocean. A mooring array, nomianally at 26^\circN between the Bahamas and the Canary Islands, deployed in Apr 2004 provides continuous measurements of the strength and variability of this circulation. With seven full years of measurements, we now examine the interannual variability of the MOC. While earlier results highlighted substantial seasonal and shorter timescale variability, there had not been significant interannual variability. The mean MOC from 1 Apr 2004 to the 31 March 2009 was 18.5 Sv with the annual means having a standard deviation of only 1.0 Sv. From 1 April 2009 to 31 March 2010, the annually averaged MOC strength was just 12.8 Sv, representing a 30\% decline. This downturn persisted from early 2009 to mid-2010. We show that the cause of the decline was not only an anomalous wind-driven event from Dec 2009--Mar 2010 but also a strengthening of the geostrophic flow. In particular, the southward flow in the top 1100~m intensified, while the deep southward return transport---particularly in the deepest layer from 3000--5000~m---weakened. This rebalancing of the transport from the deep overturning to the upper gyre has implications for the heat transported by the Atlantic. JF - Geophysical Research Letters VL - 39 KW - atlantic meridional overturning circulation KW - heat transport KW - thermohaline circulation SN - 0094-8276 TI - Observed interannual variability of the Atlantic meridional overturning circulation at 26.5N SP - 1 AV - public EP - 15 ER - TY - JOUR ID - soton370316 UR - https://eprints.soton.ac.uk/370316/ A1 - McCarthy, G.D. A1 - Smeed, D.A. A1 - Johns, W.E. A1 - Frajka-Williams, E. A1 - Moat, B.I. A1 - Rayner, D. A1 - Baringer, M.O. A1 - Meinen, C.S. A1 - Collins, J. A1 - Bryden, H.L. Y1 - 2015/01// N2 - The Atlantic Meridional Overturning Circulation (AMOC) plays a key role in the global climate system through its redistribution of heat. Changes in the AMOC have been associated with large fluctuations in the earth?s climate in the past and projections of AMOC decline in the future due to climate change motivate the continuous monitoring of the circulation. Since 2004, the RAPID monitoring array has been providing continuous estimates of the AMOC and associated heat transport at 26°N in the North Atlantic. We describe how these measurements are made including the sampling strategy, the accuracies of parameters measured and the calculation of the AMOC. The strength of the AMOC and meridional heat transport are estimated as 17.2 Sv and 1.22 PW respectively from April 2004 to October 2012. The accuracy of ten day (annual) transports is 1.5 Sv (0.9 Sv). Improvements to the estimation of the transport above the shallowest instruments and deepest transports (including Antarctic Bottom Water), and the use of the new equation of state for seawater have reduced the estimated strength of the AMOC by 0.6 Sv relative to previous publications. As new basinwide AMOC monitoring projects begin in the South Atlantic and sub-polar North Atlantic, we present this thorough review of the methods and measurements of the original AMOC monitoring array. JF - Progress in Oceanography VL - 130 KW - Atlantic Meridional Overturning Circulation KW - Ocean observing systems KW - Ocean circulation KW - Geostrophic dynamics KW - Heat transport KW - North Atlantic SN - 0079-6611 TI - Measuring the Atlantic Meridional Overturning Circulation at 26°N SP - 91 AV - public EP - 111 ER - TY - JOUR ID - soton175877 UR - https://eprints.soton.ac.uk/175877/ IS - 1 A1 - McCarthy, Gerard A1 - McDonagh, Elaine A1 - King, Brian Y1 - 2011/// N2 - New data are presented from 24°S in the South Atlantic in an investigation of the decadal variability of the intermediate and thermocline water masses at this latitude. Variation of salinity on neutral density surfaces is investigated with three transatlantic, full-depth hydrographic sections from 1958, 1983, and 2009. The thermocline is seen to freshen by 0.05 between 1983 and 2009. The freshening is coherent, basinwide, and of a larger magnitude than any errors associated with the datasets. This freshening reverses a basinwide, coherent increase in salinity of 0.03 in the thermocline between 1958 and 1983. Changes in apparent oxygen utilization (AOU) are investigated to support the salinity changes. In the thermocline of the eastern basin, a correlated relationship exists between local AOU and salinity anomalies, which is consistent with the influence of Indian Ocean Water. This correlated relationship is utilized to estimate the magnitude of Indian Ocean influence on the salinity changes in the thermocline. Indian Ocean influence explains half of the salinity changes in the eastern thermocline from 1958 to 1983 but less of the salinity change in the eastern thermocline from 1983 to 2009. Antarctic Intermediate Water properties significantly warm from 1958 through 1983 to 2009. A significant salinification and increase in AOU is evident from 1958 to 1983. Changes in the salinity of AAIW are shown to be linked with Indian Ocean influence rather than changes in the hydrological cycle. Upper Circumpolar Deep Water is seen to be progressively more saline from 1958 through 1983 to 2009. Increased Agulhas leakage and the intensification of the hydrological cycle are conflicting influences on the salinity of thermocline and intermediate waters in the South Atlantic as the former acts to increase the salinity of these water masses and the latter acts to decrease the salinity of these water masses. The results presented here offer an interpretation of the salinity changes, which considers both of these conflicting influences. JF - Journal of Physical Oceanography VL - 41 KW - Thermocline KW - Decadal variability KW - Intermediate waters KW - South Atlantic Ocean SN - 0022-3670 TI - Decadal Variability of Thermocline and Intermediate Waters at 24°S in the South Atlantic SP - 157 AV - none EP - 165 ER - TY - RPRT ID - soton44333 UR - https://eprints.soton.ac.uk/44333/ A1 - McDonagh, E.L. Y1 - 2007/// N2 - A new hydrographic section was taken across 36?N in the Atlantic Ocean during May-June 2005 aboard RRS Charles Darwin (CD171). The primary objectives of this work were to measure the meridional fluxes of heat, nutrients and CO2. This coast-to-coast, zonal data set represents the first full repeat of this section since 1981.

A total of 144 CTD/LADCP stations were sampled across the North Atlantic subtropical gyre. In addition to temperature, salinity and oxygen profiles from the CTDO2 package, water samples from a 24-bottle rosette were analysed for salinity, dissolved oxygen and inorganic nutrients at each station. In addition water samples were collected and analysed onboard ship for SF6, CFCs, pCO2, TIC and alkalinity and samples were collected for shore-based analyses for He/Tr, organic nutrients and organic carbon. Full depth velocity measurements were made at every station by up to two ADCP's mounted on the rosette frame. Throughout the cruise velocity data in the upper few hundred meters of the water column were provided by an ADCP mounted in the ship's hull, and continuous measurements of near-surface water temperature, salinity and pCO2 were made. Meteorological variables were monitored and samples of air and rainfall were periodically collected. In addition stand alone pumps were deployed 13 times and samples were collected for shore-side analyses of nitrogen isotopes, pigments and carbon and nitrogen. During the cruise two fibre optic gyrocompasses were trialled both on the bench and mounted on the rosette.

This report describes the methods used to acquire and process the data on board the ship during cruise CD171. PB - National Oceanography Centre T3 - 14 KW - Atlantic Ocean KW - atmospheric chemistry KW - biogeochemical budgets KW - carbon budgets KW - carbon tetrachloride KW - carbon KW - CFC KW - Charles Darwin KW - circulation KW - climatic changes KW - cruise CD171 2005 KW - CTD KW - Deep Western Boundary Current KW - fibre optic gyrocompass KW - FOG KW - Gulf Stream KW - helium-tritium samples KW - hydrographic section KW - Lowered ADCP KW - Meridional Overturning Circulation KW - nutrients KW - organic nutrients KW - oxygen KW - SAPS KW - shipboard ADCP KW - Stand Alone Pumping System KW - Sulphur Hexafluoride KW - Vessel Mounted ADCP M1 - project_report TI - RRS Charles Darwin Cruise CD171, 01 May - 15 Jun 2005. A trans-Atlantic hydrographic section at 36N AV - public EP - 127 ER - TY - JOUR ID - soton6056 UR - https://eprints.soton.ac.uk/6056/ IS - 7 A1 - McDonagh, E.L. A1 - Arhan, M. A1 - Heywood, K.J. Y1 - 2002/// N2 - The circulation and transport of Antarctic Bottom Water (4<45.87) in the region of the Vema Channel are studied along three WOCE hydrographic lines, the geostrophic velocities referenced to previously published direct current measurements. The primary supply of water to the deep Vema Channel is from the Argentine Basin's deep western boundary current, with no indication of an inflow from the southeast. In the northern Argentine Basin, detachment of lower North Atlantic Deep Water from the continental slope is associated with a deep thermohaline front near 34°S. To the north of this front, the upper part of the AABW bound for the Vema Channel (4<46.01) exhibits a significant NADW influence. Further modification of the throughflow water occurs near 30°30?S, where the channel orientation changes by ~50°. Southward flow of bottom water on the eastern flank of the Vema Channel, amounting to ~1.5 Sv, represents a significant countercurrent to the deep channel transport. Inclusion of this countercurrent reduces the net flow of AABW through the Vema Channel from 3.2±0.7 to 1.7±1.1 Sv. Water properties imply that the near-zero net flow over the Santos Plateau results from a near-closed cyclonic circulation fed by the deep Vema Channel throughflow. A disruption of the northward boundary current in the upper AABW (lower circumpolar water) is required by this flow pattern. The extension of the cyclonic circulation on the Santos Plateau enters the Brazil Basin as a ~1 Sv flow distinct from the outflow in the Vema Channel Extension (6.2 Sv). The high magnitude of the latter suggests a southward recirculation of bottom water near the western boundary to the north of the region of study. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 49 KW - abyssal circulation KW - deep front KW - antarctic bottom water KW - north atlantic deep water KW - vema channel KW - argentine basin KW - brazil basin KW - south atlantic SN - 0967-0637 TI - On the circulation of bottom water in the region of the Vema Channel SP - 1119 AV - none EP - 1139 ER - TY - RPRT ID - soton72086 UR - https://eprints.soton.ac.uk/72086/ A1 - McPhail, S.D. Y1 - 2010/01// N2 - There were 3 main objectives for the trials cruise: Testing of the Autosub6000 AUV, the HyBIS system (both supported by personnel from the National Oceanography Centre, Southampton), and acoustic and satellite telemetry systems (Proudman Oceanographic Laboratory, Liverpool). Specifically, the Autosub6000 trials were to test: the AUV, its systems and control to as deep as possible up to 6000 m, a new collision avoidance system based on scanned sonar collision avoidance sensor, and recently installed sensors (dual CT, LSS EH probe, magnetometer, Multibeam sonar sensors). The objectives of the HyBIS trials were to test the video guided grab system to as deep as possible, and to gain further operational experience. The objectives of the telemetry systems trials were to develop and test remote measurement technologies, deep water communication systems and a compact version of the MYRTLE (multi-year return tide level equipment) long term deep water recoverable lander. The cruise began with initial tests of the Autosub6000 AUV in the Celtic deep, followed by deep tests of the AUV to 5600m on the Iberian Abyssal plain. The majority of the work for the Autosub6000, HyBIS and the POL telemetry tests were carried out further south over and around the Casablanca seamount. A high percentage of the tests were successful, with Autosub6000 reaching a depth of 5600m. PB - National Oceanography Centre T3 - 46 KW - Acoustic Telemetry KW - Autosub KW - Autosub6000 KW - AUV KW - Cruise D343 KW - Discovery KW - HyBIS KW - NE Atlantic KW - Obstacle Avoidance KW - Oceans 2025 M1 - project_report TI - RRS Discovery Cruise 343, 27 Sep-15 Oct 2009. Deepwater trials of the Autosub6000 AUV, HyBIS, and telemetry systems AV - public EP - 55 ER - TY - RPRT ID - soton50073 UR - https://eprints.soton.ac.uk/50073/ A1 - McPhail, S.D. Y1 - 2008/01// N2 - The main objective of RRS Discovery Cruise 323 was to carry out the first deep sea field trials of the National Oceanography Centre, Southampton (NOCS) developed Autosub6000 Autonomous Underwater Vehicle. In addition, we took the opportunity, working with engineers from Proudman Oceanographic Laboratory (POL), to carry out deep water testing of integrated two way acoustic and satellite communications systems. NOCS benthic biologists also carried out seabed sampling operations at the base of the Whittard and King Arthur Canyons. As far as the Autosub6000 operations were concerned, the objectives of the cruise were completely met, with 8 dives, lasting 60 hours total and running for 278 km, to a maximum depth of 4553 m, and without faults. The POL tests of the acoustic and satellite systems were a success, and the NOCS benthic biologists successfully obtained Mega core samples at the base of the Whittard canyon. PB - National Oceanography Centre T3 - 27 KW - Autosub KW - Autosub6000 KW - AUV KW - Cruise D323 2007 KW - Discovery KW - equipment trials KW - King Arthur Canyon KW - NE Atlantic KW - North East Atlantic KW - Oceans 2025 KW - Whittard Canyon M1 - project_report TI - RRS Discovery Cruise 323, 19 Sep-03 Oct 2007. First deepwater trials of the Autosub6000 AUV AV - public EP - 38 ER - TY - JOUR ID - soton445439 UR - https://eprints.soton.ac.uk/445439/ IS - 1-2 A1 - Mcaleer, John N2 -

During the course of long voyages through the Atlantic Ocean?on their way to Africa, Asia and Australasia?British travellers experienced a variety of novel natural phenomena: the heat of the tropics, storms off the Cape, the beauty of shipboard sunsets, and unfamiliar constellations in the heavens. But it was the maritime animals that shared their shipboard space and inhabited the waters of the surrounding Atlantic that elicited the most sustained and detailed commentary from sailors and passengers. Animals were an integral part of these voyages. They travelled with passengers, as pets, curiosities and even speculative investments. The sea surrounding the ship was a veritable menagerie, encouraging travellers to speculate about the nature of the ocean and its inhabitants. They marvelled at strange creatures, compared them with familiar species, and collected them as specimens. As well as inspiring wonder and fear, encounters with maritime animals marked the journey from domestic and familiar to strange and unknown, expanding mental horizons in the process. Drawing on a wide range of first-hand accounts, this article explores the role played by maritime animals in marking the passage of travellers through the Atlantic in the Age of Sail.

VL - 22 TI - ?As pretty a thing as I have ever seen': animal encounters and Atlantic voyages, 1750?1850 AV - public EP - 23 N1 - Publisher Copyright: © 2020 The National Maritime Museum. Copyright: Copyright 2021 Elsevier B.V., All rights reserved. Y1 - 2020/// JF - Journal for Maritime Research KW - Atlantic Ocean KW - Australia KW - East India Company KW - age of sail KW - collecting KW - maritime animals KW - natural history KW - passengers KW - ship SN - 1469-1957 SP - 5 ER - TY - GEN ID - soton432127 UR - https://eprints.soton.ac.uk/432127/ A1 - Meadows, A S A1 - Ingels, Jeroen A1 - Widdicombe, Stephen A1 - Hale, Rachel A1 - Rundle, Simon Y1 - 2015/// N2 - In the near future, the marine environment is likely to be subjected to simultaneous increases in temperature and decreased pH. The potential effects of these changes on intertidal, meiofaunal assemblages were investigated using a mesocosm experiment. Artificial Substrate Units containing meiofauna from the extreme low intertidal zone were exposed for 60 days to eight experimental treatments (four replicates for each treatment) comprising four pH levels: 8.0 (ambient control), 7.7 & 7.3 (predicted changes associated with ocean acidification), and 6.7 (CO2 point-source leakage from geological storage), crossed with two temperatures: 12 °C (ambient control) and 16 °C (predicted). Community structure, measured using major meiofauna taxa was significantly affected by pH and temperature. Copepods and copepodites showed the greatest decline in abundance in response to low pH and elevated temperature. Nematodes increased in abundance in response to low pH and temperature rise, possibly caused by decreased predation and competition for food owing to the declining macrofauna density. Nematode species composition changed significantly between the different treatments, and was affected by both seawater acidification and warming. Estimated nematode species diversity, species evenness, and the maturity index, were substantially lower at 16 °C, whereas trophic diversity was slightly higher at 16 °C except at pH 6.7. This study has demonstrated that the combination of elevated levels of CO2 and ocean warming may have substantial effects on structural and functional characteristics of meiofaunal and nematode communities, and that single stressor experiments are unlikely to encompass the complexity of abiotic and biotic interactions. At the same time, ecological interactions may lead to complex community responses to pH and temperature changes in the interstitial environment. PB - PANGAEA KW - Treatment KW - Salinity KW - Salinity KW - standard deviation KW - Sample ID KW - North Atlantic KW - Fugacity of carbon dioxide (water) at sea surface temperature (wet air) KW - Taxon/taxa KW - Carbon KW - inorganic KW - dissolved KW - Alkalinity KW - total KW - Coast and continental shelf KW - Carbon KW - inorganic KW - dissolved KW - standard deviation KW - Ocean Acidification International Coordination Centre (OA-ICC) KW - Temperature KW - Amphimonhystera sp. KW - Community composition and diversity KW - Bicarbonate ion KW - standard deviation KW - Bottles or small containers/Aquaria ( 20 L) KW - Partial pressure of carbon dioxide (water) at sea surface temperature (wet air) KW - pH KW - Carbonate ion KW - standard deviation KW - Entire community KW - Aragonite saturation state KW - standard deviation KW - Temperature KW - water KW - standard deviation KW - Calcite saturation state KW - standard deviation KW - Carbonate ion KW - Biomass/Abundance/Elemental composition KW - Temperature KW - water KW - Species KW - Carbonate system computation flag KW - Replicate KW - Identification KW - Bicarbonate ion KW - Calcite saturation state KW - Colorimetric KW - Potentiometric KW - Type KW - pH KW - standard deviation KW - Partial pressure of carbon dioxide KW - standard deviation KW - Aragonite saturation state KW - Rocky-shore community KW - Temperate KW - Laboratory experiment KW - Calculated using seacarb after Nisumaa et al. (2010) KW - Calculated using CO2SYS KW - Counts KW - Alkalinity KW - total KW - standard deviation KW - Carbon dioxide KW - Benthos TI - Effects of elevated CO2 and temperature on an intertidal meiobenthic community, supplement to: Meadows, AS et al. (2015): Effects of elevated CO2 and temperature on an intertidal meiobenthic community. Journal of Experimental Marine Biology and Ecology, 469, 44-56 AV - none ER - TY - JOUR ID - soton378191 UR - https://eprints.soton.ac.uk/378191/ IS - 1-2 A1 - Mecking, J.V. A1 - Keenlyside, N.S. A1 - Greatbatch, R.J. Y1 - 2014/07// N2 - Observations show a multidecadal signal in the North Atlantic ocean, but the underlying mechanism and cause of its timescale remain unknown. Previous studies have suggested that it may be driven by the North Atlantic Oscillation (NAO), which is the dominant pattern of winter atmospheric variability. To further address this issue, the global ocean general circulation model, Nucleus for European Modelling of the Ocean (NEMO), is driven using a 2,000 years long white noise forcing associated with the NAO. Focusing on key ocean circulation patterns, we show that the Atlantic Meridional Overturning Circulation (AMOC) and Sub-polar gyre (SPG) strength both have enhanced power at low frequencies but no dominant timescale, and thus provide no evidence for a oscillatory ocean-only mode of variability. Instead, both indices respond linearly to the NAO forcing, but with different response times. The variability of the AMOC at 30°N is strongly enhanced on timescales longer than 90 years, while that of the SPG strength starts increasing at 15 years. The different response characteristics are confirmed by constructing simple statistical models that show AMOC and SPG variability can be related to the NAO variability of the previous 53 and 10 winters, respectively. Alternatively, the AMOC and the SPG strength can be reconstructed with Auto-regressive (AR) models of order seven and five, respectively. Both statistical models reconstruct interannual and multidecadal AMOC variability well, while on the other hand, the AR(5) reconstruction of the SPG strength only captures multidecadal variability. Using these methods to reconstruct ocean variables can be useful for prediction and model intercomparision. JF - Climate Dynamics VL - 43 KW - North Atlantic KW - NAO KW - Atlantic Multidecadal Variability KW - Sub-polar gyre KW - Stochastic KW - OGCM SN - 0930-7575 TI - Stochastically-forced multidecadal variability in the North Atlantic: a model study SP - 271 AV - none EP - 288 ER - TY - JOUR ID - soton383875 UR - https://eprints.soton.ac.uk/383875/ IS - 9-10 A1 - Mecking, Jennifer V. A1 - Keenlyside, Noel S. A1 - Greatbatch, Richard J. Y1 - 2015/09// N2 - The Atlantic meridional overturning circulation (AMOC) and the subpolar gyre (SPG) are important elements in mechanisms for multidecadal variability in models in the North Atlantic Ocean. In this study, a 2000-year long global ocean model integration forced with the atmospheric patterns associated with a white noise North Atlantic Oscillation (NAO) index is shown to have three distinct timescales of North Atlantic Ocean variability. First, an interannual timescale with variability shorter than 15 years, that can be related to Ekman dynamics. Second, a multidecadal timescale, on the 15- to 65-year range, that is mainly concentrated in the SPG region and is controlled by constructive interference between density anomalies around the gyre and the changing NAO forcing. Finally, the centennial timescales, with variability longer than 65 years, that can be attributed to the ocean being in a series of quasi-equilibrium states. The relationship between the ocean?s response and the NAO index differs for each timescale; the 15-year and shorter timescales are directly related to the NAO of the same year, 15- to 65-year timescales are dependent on the NAO index in the last 25?30 years in a sinusoidal sense while the 65-year and longer timescales relate to a sum of the last 50?80 years of the NAO index. JF - Ocean Dynamics VL - 65 KW - North Atlantic KW - NAO KW - Atlantic multidecadal variability KW - AMOC KW - Subpolar gyre KW - Stochastic KW - OGCM SN - 1616-7341 TI - Multiple timescales of stochastically forced North Atlantic Ocean variability: A model study SP - 1367 AV - none EP - 1381 ER - TY - JOUR ID - soton437799 UR - https://eprints.soton.ac.uk/437799/ A1 - Meredyk, Shawn P. A1 - Edinger, Evan A1 - Piper, David J. W. A1 - Huvenne, Veerle A. I. A1 - Hoy, Shannon A1 - Ruffman, Alan Y1 - 2020/01/30/ N2 - Deep-sea mounds can have a variety of origins and may provide hard-substrate features in depths that are normally dominated by mud. Orphan Knoll, a 2 km high bedrock horst off northeast Newfoundland, hosts more than 200 mounds, or mound complexes, of unknown composition, in water depths of 1720?2500 m. Most mounds are 10?600 m high, with average mound height 187 m, and 1?3 km wide. The study objective was to characterize the size, shape, orientation, and composition of the enigmatic Orphan Knoll mounds, in order to determine their age and origin. Archival ship-based side-scan sonar, multibeam sonar, airgun, high-resolution sparker and 3.5 kHz acoustic sub-bottom profiling, and newly acquired ship-based multibeam sonar, video transects by remotely operated vehicle (ROV), rock samples, and near-bottom multibeam sonar data were analyzed. Four mounds were studied during two ROV dives. Archival sidescan sonar data show > 200 mounds. Sparker profiles show that the mound crests are covered by condensed stratified Quaternary sediment and airgun seismic data show faults reaching near the seafloor. New multibeam sonar data show mounds are dominantly conical to elliptical in shape, but without preferred orientation or alignment. Remotely operated vehicle (ROV) transects and near-bottom multibeam showed that three mounds were rounded and symmetrically arranged, while a fourth was more asymmetrical, with steep faces on the southwestern and southeastern flanks, where finely bedded to massive sedimentary bedrock outcropped dipping 15?45°SW. Rock samples from the mounds include Eocene calcareous ooze and mid-Miocene bedded pelagic limestone. Thick ferromanganese crusts were found on many surfaces, obscuring possible outcrops from physical sampling. Polymetallic nodules were found on the slope of one mound. Ice-rafted detritus, including igneous and metamorphic rocks and Paleozoic limestone and dolostone, was common in the sediments immediately surrounding the mounds. Quaternary sub-fossil solitary scleractinian corals accumulated over a span of at least 0.18 Ma at the base of one mound. The presence of uplifted condensed Eocene-Miocene rocks on the mounds and faulting in seismic profiles suggest uplift during reactivation of old rift-related faults during the Neogene, with seabed mass wasting creating residual mounds, which were then draped by Quaternary proglacial muds. Sculpting of hemipelagic Quaternary sediment by bottom currents probably contributed to mound morphology. JF - Frontiers in Marine Science VL - 6 KW - Northwest Atlantic KW - Orphan Knoll KW - cold-water corals KW - deep-sea KW - mound KW - multibeam sonar SN - 2296-7745 TI - Enigmatic deep-water mounds on the Orphan Knoll, Labrador Sea SP - 1 AV - public EP - 23 ER - TY - JOUR ID - soton350042 UR - https://eprints.soton.ac.uk/350042/ IS - 6 A1 - Mielke, C. A1 - Frajka-Williams, E. A1 - Baehr, J. Y1 - 2013/03/27/ N2 - Timeseries of the observational estimate of the Atlantic meridional overturning circulation (AMOC) have recently become available, but so far no contemporaneous relation has been documented between them. Here, we analyze the variability of the 26°N RAPID and the 41°N ARGO-based AMOC estimates on seasonal timescales, and we compare them to a simulation from a high-resolution NCEP-forced ocean model. In our analysis of the observed timeseries, we find that the seasonal cycles of the non-Ekman component of the AMOC between 26°N and 41°N are 180-degrees out-of-phase. Removing the mean seasonal cycle from each timeseries, the residuals have a non-stationary covariability. Our results demonstrate that the AMOC is meridionally covariable between 26°N and 41°N at seasonal timescales. We find the same covariability in the model, though the phasing differs from the observed phasing. This may offer the possibility of inferring AMOC variations and associated climate anomalies throughout the North Atlantic from discontinuous observations. JF - Geophysical Research Letters VL - 40 KW - north atlantic KW - AMOC KW - seasonal variability SN - 0094-8276 TI - Observed and simulated variability of the AMOC at 26°N and 41°N SP - 1159 AV - public EP - 1164 ER - TY - JOUR ID - soton360966 UR - https://eprints.soton.ac.uk/360966/ A1 - Miller, Peter I. A1 - Read, Jane F. A1 - Dale, Andrew C. Y1 - 2013/12/15/ N2 - Thermal fronts detected using multiple satellite sensors have been integrated to provide new information on the spatial and seasonal distribution of oceanic fronts in the North Atlantic. The branching of the North Atlantic Current (NAC) as it encounters the Mid-Atlantic Ridge (MAR) is reflected in surface thermal fronts, which preferentially occur at the Charlie Gibbs Fracture Zone (CGFZ) and several smaller fracture zones. North of the CGFZ there are few thermal fronts, contrasting with the region to the south, where there are frequent surface thermal fronts that are persistent seasonally and interannually. The alignment of the fronts confirms that the shallower Reykjanes Ridge north of the CGFZ is more of a barrier to water movements than the ridge to the south. Comparison of front distributions with satellite altimetry data indicates that the MAR influence on deep ocean currents is also frequently exhibited in surface temperature. The improved spatial and temporal resolution of the front analysis has revealed consistent seasonality in the branching patterns. These results contribute to our understanding of the variability of the NAC, and the techniques for visualising oceanic fronts can be applied in other regions to reveal details of surface currents that cannot be resolved using satellite altimetry or in situ measurements. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 98 KW - Oceanic fronts KW - Remote sensing KW - North Atlantic Current KW - Ocean currents KW - Ocean circulation KW - SST KW - Mid-Atlantic Ridge KW - Charlie Gibbs Fracture Zone KW - Altimetry SN - 0967-0645 TI - Thermal front variability along the North Atlantic Current observed using microwave and infrared satellite data SP - 244 AV - none EP - 256 ER - TY - JOUR ID - soton439790 UR - https://eprints.soton.ac.uk/439790/ IS - 7 A1 - Milligan, Rosanna J. A1 - Scott, E. Marian A1 - Jones, Daniel O. B. A1 - Bett, Brian J. A1 - Jamieson, Alan J. A1 - O?brien, Robert A1 - Pereira Costa, Sofia A1 - Rowe, Gilbert T. A1 - Ruhl, Henry A. A1 - Smith, Ken L. A1 - De Susanne, Philippe A1 - Vardaro, Michael F. A1 - Bailey, David M. N2 - Animal migrations are of global ecological significance, providing mechanisms for the transport of nutrients and energy between distant locations. In much of the deep sea (>200 m water depth), the export of nutrients from the surface ocean provides a crucial but seasonally variable energy source to seafloor ecosystems. Seasonal faunal migrations have been hypothesized to occur on the deep seafloor as a result, but have not been documented. Here, we analyse a 7.5?year record of photographic data from the Deep?ocean Environmental Long?term Observatory Systems seafloor observatories to determine whether there was evidence of seasonal (intra?annual) migratory behaviours in a deep?sea fish assemblage on the West African margin and, if so, identify potential cues for the behaviour. Our findings demonstrate a correlation between intra?annual changes in demersal fish abundance at 1,400 m depth and satellite?derived estimates of primary production off the coast of Angola. Highest fish abundances were observed in late November with a smaller peak in June, occurring approximately 4 months after corresponding peaks in primary production. Observed changes in fish abundance occurred too rapidly to be explained by recruitment or mortality, and must therefore have a behavioural driver. Given the recurrent patterns observed, and the established importance of bottom?up trophic structuring in deep?sea ecosystems, we hypothesize that a large fraction of the fish assemblage may conduct seasonal migrations in this region, and propose seasonal variability in surface ocean primary production as a plausible cause. Such trophic control could lead to changes in the abundance of fishes across the seafloor by affecting secondary production of prey species and/or carrion availability for example. In summary, we present the first evidence for seasonally recurring patterns in deep?sea demersal fish abundances over a 7?year period, and demonstrate a previously unobserved level of dynamism in the deep sea, potentially mirroring the great migrations so well characterized in terrestrial systems. VL - 89 TI - Evidence for seasonal cycles in deep-sea fish abundances:: A great migration in the deep SE Atlantic? AV - public EP - 1603 N1 - Funding Information: The authors would like to thank Mr John Polanski and Dr Stewart Chalmers for their assistance with data collection and processing, as well as the captains and crews of the field support vessels for their expertise in deploying and recovering the DELOS observatory modules. This research was funded by BP Exploration and BP Angola, and is a collaboration between Glasgow University (UK), the National Oceanography Centre (UK), Oceanlab (University of Aberdeen, UK), the Instituto Nacional de Investiga??o Pesqueira (Angola), Monterey Bay Aquarium Research Institute (USA), Texas A&M University (USA) and Sonangol. R.J.M. was funded by a NERC studentship (NE/I528369). D.O.B.J., B.J.B. and H.A.R. received support from the UK Natural Environment Research Council via National Capability funding of ?Climate Linked Atlantic Sector Science? (CLASS; NE/R015953/1). The authors declare no competing interests. Publisher Copyright: © 2020 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society Y1 - 2020/07/01/ JF - Journal of Animal Ecology KW - Africa KW - SE Atlantic Ocean KW - connectivity KW - deep sea KW - fishes KW - migration SN - 0021-8790 SP - 1593 ER - TY - JOUR ID - soton7896 UR - https://eprints.soton.ac.uk/7896/ IS - 1-4 A1 - Mills, Rachel A. A1 - Wells, Deborah M. A1 - Roberts, Stephen Y1 - 2001/07/01/ N2 - The rare earth element (REE) geochemistry and Nd isotopic composition of marine ferromanganese crusts allow insight into their environment of deposition. We present REE along with major and trace element data from a suite of samples collected near an active hydrothermal site from the Mid-Atlantic Ridge and demonstrate extreme REE variability over short spatial scales. Both positive and negative Ce anomalies are observed, along with varied fractionation of the REEs. Some of the Fe?Mn crusts are formed directly from low-temperature hydrothermal fluids, channelled over 3 km from any high-temperature vent site. A significant hydrothermal component is observed in one Fe?Mn crust sampled. Other samples, collected from the same area, are predominantly hydrogenous and form at a wide range of accumulation rates depending on the hydrothermal plume input. The identification of extreme heterogeneity in source and depositional environment within one hydrothermal field suggests that (1) this variability can be resolved both spatially and temporally within a fossil hydrothermal deposit and (2) the integrated record provided by bulk analysis should be interpreted with caution. JF - Chemical Geology VL - 176 KW - rare earth elements KW - geochemistry KW - mid atlantic ridge KW - neodymium isotopes KW - ferromanganese crusts KW - trans atlantic geotraverse KW - manganese nodules KW - geology SN - 0009-2541 TI - Genesis of ferromanganese crusts from the TAG hydrothermal field SP - 283 AV - none EP - 293 ER - TY - JOUR ID - soton1368 UR - https://eprints.soton.ac.uk/1368/ IS - B11 A1 - Minshull, T.A. A1 - Bruguier, N.J. A1 - Brozena, J.M. Y1 - 2003/11// N2 - The Mid-Atlantic Ridge at 8?9°S is characterized by a transition from axial valley to axial high and recent episodes of ridge jumping and ridge propagation. We present constraints on the structure of 0?4 Ma crust in this region on the basis of the analysis of wide-angle seismic data from a grid of profiles across and parallel to the current and abandoned spreading centers. A 350?800 m thick oceanic layer 2A, interpreted as high-porosity extrusive basalts, is underlain by a ~2.0?2.5 km layer 2B with velocities which increase with age and decrease in the vicinity of the pseudofaults. Layer 3 velocities are uniform across the area except for a possible localized anomaly at the ridge axis. The crustal thickness varies from 6?7 km near the pseudofaults formed by ridge propagation to 9?10 km at the segment center of the recently (~0.3 Ma) abandoned spreading center. Seismically determined crustal thickness and density variations and age-related lithospheric cooling can plausibly account for all observed variations in gravity across the area, and there is no requirement for the thicker crust at the segment center to be underlain by hot mantle. The transition from axial valley to axial high occurs at a crustal thickness of ~8 km. JF - Journal of Geophysical Research VL - 108 KW - mid-ocean ridge KW - South Atlantic KW - crustal structure KW - morphology KW - seismic velocity. SN - 0148-0227 TI - Seismic structure of the Mid-Atlantic Ridge, 8-9S SP - 02513 AV - none EP - [22pp] ER - TY - JOUR ID - soton21064 UR - https://eprints.soton.ac.uk/21064/ IS - 3 A1 - Moore, C.M. A1 - Lucas, M.I. A1 - Sanders, R. A1 - Davidson, R. Y1 - 2005/// N2 - Phytoplankton physiological data collected throughout the Iceland Basin and Rockall Trough during the North Atlantic spring bloom from May to June 2001 are presented. Physiological parameters including the maximum photochemical quantum efficiency (Fv/Fm) and the functional absorption cross section of photosystem II (?PSII) were measured using fast repetition rate fluorometry. Information on the taxonomic and pigment characteristics of the phytoplankton populations was also collected, with pigment data being used to reconstruct absorption spectra. Significant changes in the physiological properties of PSII were found to be associated with the progression of the spring bloom from diatom to flagellate domination. Changes in both community composition and physiology were in turn correlated with environmental parameters. Lower Fv/Fm, higher ?PSII and corresponding decreases in cell size were associated with the observed decrease of nutrients that accompanied increasing stratification. Differences in ?PSII were primarily associated with the changing pigment composition of the phytoplankton populations, with the largest changes appearing to be governed by the amount of absorption by photosynthetic carotenoids. The physiological state of PSII was thus found to be an indicator of bloom status and community structure in this productive temperate region principally as a result of taxon specific variability. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 52 KW - phytoplankton KW - fluorescence KW - photosynthesis KW - pigments KW - spring bloom KW - fast repetition rate fluorometry KW - northeast atlantic ocean TI - Basin-scale variability of phytoplankton bio-optical characteristics in relation to bloom state and community structure in the Northeast Atlantic SP - 401 AV - none EP - 419 ER - TY - JOUR ID - soton208995 UR - https://eprints.soton.ac.uk/208995/ A1 - Morigi, C. A1 - Sabbatini, A. A1 - Vitale, G. A1 - Pancotti, I. A1 - Gooday, A.J. A1 - Duineveld, G.C.A. A1 - De Stigter, H.C. A1 - Danovaro, R. A1 - Negri, A. Y1 - 2012/01// N2 - Cold-water coral (CWC) ecosystems are hotspots of macro- and microfaunal biodiversity and provide refuge for a wide variety of deep-sea species. We investigated how the abundance and biodiversity of ?live? (Rose Bengal stained) foraminifera varies with, and is related to, the occurrence of CWC on the Rockall Bank (NE Atlantic). Qualitative and quantitative analyses were performed on 21 replicate samples from 8 deep-sea stations, including 4 stations on CWC-covered carbonate mounds at depths of 567?657 m, and 4 stations on the adjacent slope at depths of 469?1958 m where CWC were absent. This sampling strategy enabled us to demonstrate that sediments surrounding the living CWC were characterised by higher foraminiferal abundance and biodiversity than open-slope sediments from the same area. A total of 163 foraminiferal species was identified. The dominant species in CWC sediments were: Spirillina vivipara, Allogromiid sp. 1, Globocassidulina subglobosa, Adercotryma wrighti, Eponides pusillus, Ehrenbergina carinata, Planulina ariminensis, Trochammina inflata and Paratrochammina challengeri. Foraminifera were nearly absent in adjacent open slope areas subject to strong tidal currents and characterised by coarse grained deposits. We suggest that CWC create a heterogeneous three-dimensional substrate offering microhabitats to a diverse benthic foraminiferal community. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 59 KW - Foraminifera KW - Biodiversity KW - Cold water coral KW - High energy/strong currents environment KW - North Atlantic SN - 0967-0637 TI - Foraminiferal biodiversity associated with cold-water coral carbonate mounds and open slope of SE Rockall Bank (Irish continental margin?NE Atlantic) SP - 54 AV - none EP - 71 ER - TY - JOUR ID - soton337009 UR - https://eprints.soton.ac.uk/337009/ A1 - Morris, Kirsty A1 - Tyler, Paul A. A1 - Murton, Bramley A1 - Rogers, Alex D. Y1 - 2012/// N2 - The deep-sea floor below 3000 m occupies 50% of the surface of the planet and is composed mainly of fine sediments. Most studies of deep-sea benthic fauna have concentrated on soft sediments with little sampling in rocky areas and even less on non-vent mid-ocean ridges. To assess the distribution and abundance of coral between 2500 m and 3500 m depths, video footage from the ROV Isis taken during a cruise to the Axial Volcanic Ridge (AVR) of the Mid-Atlantic Ridge at approx 45°30? N was analysed. Abundances per 100 m were calculated and mapped using Arc GIS, with a maximum of 59 being observed. 20 putative species were identified. Scleractinia were absent from the observed area and the coral fauna was dominated by Octocorallia. The data were separated into four substratum types, sediment, sloped rock, flat rock and mixed substratum, with both abundance and community being compared. Sedimented and rocky areas had different coral communities with sediment having a higher occurrence of Pennatulidae and Chrysogorgidae than rock. Sloped rock had the highest abundance of corals. We suggest that this increase in abundance reflects higher food availability as well as the solid substratum on which coral larvae settle. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 62 KW - Mid Atlantic Ridge KW - Corals KW - Rock KW - Gorgonians KW - Octocorals SN - 0967-0637 TI - Lower bathyal and abyssal distribution of coral in the axial volcanic ridge of the Mid-Atlantic Ridge at 45°N SP - 32 AV - none EP - 39 ER - TY - JOUR ID - soton19330 UR - http://www.int-res.com/articles/meps2005/287/m287p045.pdf A1 - Mourino, B. A1 - Fernandez, E. A1 - Pingree, R.D. A1 - Sinha, B. A1 - Escanez, E. A1 - de Armas, D. Y1 - 2005/// N2 - An oceanographic cruise was carried out in the subtropical NE Atlantic in April 1999 with the aim of investigating the role of the Azores Current, the STORM (subtropical oceanic rings of magnitude) cyclonic eddies and the Great Meteor Tablemount in triggering phytoplankton production. This information combined with previous studies allowed us to determine the role of these features in the carbon budget of the photic layer in this oligotrophic region. The results suggest that mesoscale dynamics, although modifying hydrographic characteristics and phytoplankton spatial distribution, do not appear to significantly affect primary production in the NE subtropical Atlantic. JF - Marine Ecology Progress Series VL - 287 KW - mesoscale features KW - phytoplankton biomass KW - primary production KW - carbon budget KW - NE subtropical Atlantic TI - Constraining the effect of mesoscale features on the carbon budget of the photic layer in the NE subtropical Atlantic SP - 45 AV - none EP - 52 ER - TY - JOUR ID - soton6028 UR - https://eprints.soton.ac.uk/6028/ A1 - Murray, J. Y1 - 2002/// JF - Newsletter of Micropalaeontology VL - No. 66 KW - MUCK DEEP KW - BENTHIC COMMUNITIES KW - SPECIES DIVERSITY KW - NORTH ATLANTIC OSCILLATION KW - PALAEOCLIMATOLOGY KW - GEOLOGY TI - Holocene history of an enclosed basin on the shelf west of Scotland AV - none ER - TY - RPRT ID - soton320 UR - https://eprints.soton.ac.uk/320/ A1 - Murton, B.J. Y1 - 1996/// N2 - Cruise CD95 sailed on the RRS Charles Darwin from Barry, South Wales to Ponta Delgada, Azores, 8 August to 14 September 1995. The objectives of the expedition, FLUXES I, were to investigate the energy, chemical and biological fluxes from the Broken Spur hydrothermal vent field at 29°10'N (segment 17 o f the Mid Atlantic Ridge). The methodology of the experiment depended on using the bathymetry and bottom-water structure of segment 17 as a natural laboratory in which the fluxes are integrated over time. The water column density structure is such that the rise height of the hydrothermal plume is effectively limited to a depth greater than that of the surrounding axial valley walls. The only opening is to the south where waters external to the ridge system have access to segment 17. Philosophically, the experiment must measure the chemical, energetic and biological inventory for segment 17. Then by measuring the exchange of vent affected water from the segment with water external to the system, the integration of the components can be deconvolved and fluxes derived. This experiment, funded by the UK's BRIDGE initiative, was designed to form the basis for further data collection to measure the hydrothermal fluxes in segment 17, as endorsed by the InterRidge Meso-Scale Workshop held in Cambridge, UK, on 26 and 27 June 1995. The work was funded by NERC research grant GST/02/1125 to Drs Murton, B.J., German, C.G., Herring, P. and Dixon, D. PB - Southampton Oceanography Centre, University of Southampton T3 - 2 KW - 29°N 43°W KW - basalts KW - biology KW - bottom photography KW - BRIDGE KW - BRIDGET KW - Broken Spur KW - Charles Darwin KW - chemistry KW - cruise 95 1995 KW - CTD KW - current meters KW - DNA KW - FLUXES I KW - geology KW - hydrothermal activity KW - Interidge Mesoscale Programme KW - Mid Atlantic Ridge KW - moorings KW - NERC KW - pelagic fisheries KW - petrology KW - RMT KW - Shrimp KW - videotape recording KW - water samples M1 - project_report TI - RRS Charles Darwin Cruise CD95, 08 Aug-14 Sep 1995. The FLUXES I Programme (hydrothermal energy, chemical and biological fluxes at a ridge segment meso-scale) AV - public EP - 86 ER - TY - CHAP ID - soton6168 UR - https://eprints.soton.ac.uk/6168/ A1 - Murton, B.J. A1 - Ferreira, P. A1 - Monteiro, J.H. Y1 - 2001/// PB - Intergovernmental Oceanographic Commission T3 - 175 KW - ERUPTIONS KW - SEAMOUNTS KW - MID ATLANTIC RIDGE KW - HYDROTHERMAL VENTS KW - GEOLOGY TI - Volcanism and hydrothermal venting of the Mid-Atlantic Ridge: evolution of explosive seamount volcanism: evidence from 37 degrees N on the mid-atlantic ridge SP - 70 AV - none EP - 71 T2 - Geological Processes on Deep-Water European Margins: International Conference and Ninth Post-Cruise Meeting of the Training-Through-Research Programme, devoted to the 10th Anniversary, Moscow-Mozhenka, Russia, 28 January-2 February 2001 ER - TY - JOUR ID - soton8844 UR - http://www.agu.org/journals/gl/gl0010/1999GL002394/pdf/1999GL002394.pdf IS - 10 A1 - Murton, B.J. A1 - Redbourn, L.J. Y1 - 2000/// JF - Geophysical Research Letters VL - 27 KW - MID ATLANTIC RIDGE KW - BOTTOM WATER KW - TEMPERATURE KW - SALINITY KW - TEMPERATURE ANOMALIES KW - HEAT TRANSFER SN - 0094-8276 TI - Oceanographic evidence for a transient geothermal event affecting the Mid-Atlantic Ridge SP - 1507 AV - none EP - 1510 ER - TY - JOUR ID - soton42885 UR - https://eprints.soton.ac.uk/42885/ IS - 3-4 A1 - Nedelec, F. A1 - Statham, P.J. A1 - Mowlem, M. N2 - Shelf break systems are highly dynamic environments. However little is known about the influence that benthic interactions and water mass mixing may have on vertical distributions of iron in these systems. Dissolved Fe (< 0.4 ?m) concentrations were measured in samples from nine vertical profiles across the upper slope (150?2950 m water depth) at the Atlantic Ocean?Celtic Sea shelf break. Dissolved iron concentrations varied between less than 0.2 and 5.4 nM, and the resulting detailed section showed evidence of a range of processes influencing the Fe distributions. The near sea floor data were interpreted in terms of release and removal processes. The concentrations of dissolved Fe present in near seabed waters were consistent with release of Fe from in situ remineralisation of particulate organic matter at two upper slope stations, and possibly release from pore water upon resuspension on shelf. Lateral transport of dissolved iron was evident from elevated Fe concentrations in an intermediate nepheloid layer and its advection along isopycnals. Surface waters at the shelf break also showed evidence of vertical mixing of deeper iron-rich waters. These waters contained macronutrients that sustained primary productivity in these otherwise nutrient-depleted surface waters. The data also suggest some degree of stabilisation of relatively high concentrations of iron, presumably through ligand association or as colloids. This study supports the view that lateral export of dissolved iron to the interior of the ocean from shelf and coastal zones and may have important implications for the global budget of oceanic iron. VL - 104 TI - Processes influencing dissolved iron distributions below the surface at the Atlantic Ocean - Celtic Sea shelf edge AV - none EP - 170 N1 - Reprinted in: Marine Chemistry, 104(3-4), 2007, 156-170, for special issue: Dedicated to the memory of Professor Roland Wollast. Y1 - 2007/03// JF - Marine Chemistry KW - Dissolved iron KW - Particulate organic matter oxidation KW - Transport processes KW - Intermediate nepheloid layers KW - Vertical mixing KW - Northeast Atlantic KW - Celtic Sea shelf edge SN - 0304-4203 SP - 156 ER - TY - RPRT ID - soton243 UR - https://eprints.soton.ac.uk/243/ A1 - New, A.L. Y1 - 2003/// N2 - RRS Charles Darwin Cruise 141, SCIPIO (Satellite Calibration and Interior Physics of the Indian Ocean) provided a multidisciplinary survey of the Mascarene Ridge system in the western Indian Ocean. The principal objectives were to (a) study the flow of water masses through the Ridge system, together with their decadal-timescale variability, (b) assess the energy fluxes and mixing arising from internal waves, (c) collect in situ data for the calibration of sea-surface temperature and ocean colour sensors on the ENVISAT satellite, (d) investigate the biogeochemical properties of the water masses, and (e) measure the heat fluxes and winds, and the airflow disturbance around the ship.

The survey comprised three sections parallel with the Ridge near 64°, 60° and 57° E, joined by two other sections at 8° and 20°S. The sections comprised CTD, LADCP, and biogeochemistry (nutrients, phytoplankton, zooplankton, biogenic gases, CFC tracers and light levels) stations to full ocean depth, at typical spacings of about 60-80 nm.

At several of these the CTD and LADCP were cycled continuously for a semidiurnal tidal cycle to study the internal waves, and the smaller 12-bottle CTD frame was used throughout (usually with 6 bottles) in order to reduce mixing effects from the trailing wake. Underway measurements were made with the shipboard ADCP, TSG, radiosondes, XBTs, and of surface meteorology, skin surface temperature, and zooplankton.

The ship's EM12 swath bathymetry system was operated continuously, and used to study certain key areas in detail. In addition, MMP (a cycling CTD) and bottom-mounted ADCP moorings were successfully laid and recovered near 8°S, 60°E, and a first deployment of the ARGODOT turbulence probe was made near 20°S, 57.5°E. PB - Southampton Oceanography Centre, University of Southampton T3 - 41 KW - acoustic doppler current profiler KW - adcp KW - argodot KW - autoflux KW - biology KW - cfc KW - charles darwin KW - cruise 141 2002 KW - em12 KW - indian ocean KW - internal waves KW - ladcp KW - lightfish KW - light levels KW - lowered adcp KW - mascarene ridge KW - meteorological measurements KW - methyl halides KW - mixing KW - nutrients KW - oxygen KW - phytoplankton KW - plant pigments KW - radiosonde KW - south atlantic KW - scipio KW - sister KW - south equatorial current KW - swath bathymetry KW - tracer chemistry KW - tsg KW - xbt KW - zooplankton M1 - project_report TI - RRS Charles Darwin Cruise 141, 01 Jun-11 Jul 2002. Satellite Calibration and Interior Physics of the Indian Ocean: SCIPIO AV - public EP - 92 ER - TY - JOUR ID - soton272 UR - https://eprints.soton.ac.uk/272/ IS - 8/10 A1 - New, A.L. A1 - Smythe-Wright, D. N2 - An investigation is made of the circulation and structure of the water masses in the Rockall Trough in spring, combining the results of a recent synoptic survey (May 1998) with those from a high-resolution ocean circulation model. In the near-surface layer, saline flows are carried northwards by a "Shelf Edge Current" around the eastern slopes, possibly with some branching in the northern Trough. Fresher waters from the west inflow between 52 and 538N and partially mix with these saline flows in the southern Trough, so that waters of intermediate salinity are also swept northwards. In the southern approaches to the Trough, Labrador Sea Water (LSW) also flows strongly in from the west between 52 and 538N, and while much of this turns south, a proportion penetrates north to join a cyclonic gyre in the Trough extending to 56.58N. The northwestern limb of this gyre is fed by, and mixes with, more saline waters which result from overflows across the Wyville?Thomson Ridge. Furthermore, salinity and CFC data suggest episodic inflow of LSW into the central Trough. The circulation of the North East Atlantic Deep Water in the Trough follows a cyclonic pattern similar to, and lying below, that of the LSW. The Wyville?Thomson Ridge overflows in the model extend to higher densities than in the survey, are topographically steered southwestward down the Feni Ridge system, and eventually join a deep cyclonic circulation in the North East Atlantic basin. Overall, the model and the observations are in good agreement, particularly in the central Rockall Trough, and this has allowed conclusions to be drawn which are significantly more robust than those which would result from either the survey or the model alone. In particular, we have been able to infer cyclonic circulation pathways for the intermediate and deeper waters in the Rockall Trough for (we believe) the first time. The study has also contributed to an ongoing community effort to assess the realism of, and improve, our current generation of ocean circulation models. VL - 21 TI - Aspects of the circulation in the Rockall Trough AV - restricted EP - 810 N1 - Accepted version (proof version) Y1 - 2001/05// JF - Continental Shelf Research KW - Northeast Atlantic Ocean KW - Rockall Trough KW - ocean circulation KW - upper ocean KW - Labrador Seawater KW - Northeast Atlantic deep water KW - observations KW - ocean model SN - 0278-4343 SP - 777 ER - TY - JOUR ID - soton6052 UR - http://www.gsajournals.org/gsaonline/?request=get-abstract&issn=0091-7613&volume=30&page=299 IS - 4 A1 - Norris, R.D. A1 - Bice, K.L. A1 - Magno, E.A. A1 - Wilson, P.A. Y1 - 2002/// JF - Geology VL - 30 KW - temperature KW - Cretaceous KW - planktonic foraminifera KW - stable isotopes KW - Atlantic. SN - 0091-7613 TI - Jiggling the tropical thermostat in the Cretaceous hothouse SP - 299 AV - none EP - 302 ER - TY - JOUR ID - soton20366 UR - https://eprints.soton.ac.uk/20366/ IS - 1-2 A1 - O Cofaigh, C. A1 - Dowdeswell, J.A. A1 - Kenyon, N.H. Y1 - 2006/// N2 - The Lofoten Basin Channel forms one of two major submarine channels on the Norwegian margin of the Polar North Atlantic. The channel system connects upslope with the Andøya Canyon which is the only canyon to cut back across the continental shelf in this region. High-resolution geophysical records, including multibeam swath?bathymetric and TOBI side-scan sonar data, show that the distal part of the channel system is braided and connects to a low-gradient (0.01°), channel-mouth lobe on the abyssal plain of the Lofoten Basin. Geophysical data indicate that the channel floor is composed of sandy material deposited by turbidity currents. These turbidity currents spilled out over the channel sides to deposit acoustically stratified sediment in the channel levees. Side-scan sonar data supplemented by sediment cores indicate that the channel-mouth lobe is sandy in composition. The Lofoten Channel and its associated channel-mouth lobe is therefore related to turbidity current activity and formation of the system appears to pre-date the Holocene. Morphological variation between the upper reaches of the Andøya Canyon/Lofoten Channel system and the submarine channels of the Greenland Basin is proposed to relate to differences in the nature of the flows feeding both systems. The Andøya Canyon/Lofoten Channel system bears strong similarities to some mid- and low-latitude submarine fans with respect to its morphology and architecture. JF - Marine Geology VL - 226 KW - polar north atlantic KW - lofoten channel KW - submarine channels KW - turbidity currents SN - 0025-3227 TI - Geophysical investigations of a high-latitude submarine channel system and associated channel-mouth lobe in the Lofoten Basin, Polar North Atlantic SP - 41 AV - none EP - 50 ER - TY - JOUR ID - soton44223 UR - http://springerlink.metapress.com/content/hr6k523777718326/?p=637fbb44f3f64940af2e1eba86cf6c57&pi=20 IS - 11 A1 - Olabarria, C. Y1 - 2006/// N2 - Despite the plethora of studies, geographic patterns of diversity in deep sea remain subject of speculation. This study considers a large dataset to examine the faunal change and depth-diversity gradient of prosobranch molluscs in the Porcupine Seabight and adjacent Abyssal Plain (NE Atlantic). Rates of species succession (addition and loss) increased rapidly with increasing depth and indicated four possible areas of faunal turnover at about 700, 1600, 2800 and 4100 m. Depth was a significant predictor of diversity, explaining nearly a quarter the variance. There was a pattern of decreasing diversity downslope from ~250 m to ~1500?1600 m, followed by an increase to high values at about 4000 m and then again, a fall to ~4915 m. Processes causing diversity patterns of prosobranchs in the Porcupine Seabight and adjacent Abyssal Plain are likely to differ in magnitude or type, from those operating in other Atlantic areas. JF - Biodiversity and Conservation VL - 15 KW - deep sea KW - diversity KW - faunal turnover KW - Northeastern Atlantic KW - Porcupine Abyssal Plain KW - Porcupine Seabight KW - prosobranchs TI - Faunal change and bathymetric diversity gradient in deep-sea prosobranchs from Northeastern Atlantic SP - 3685 AV - none EP - 3702 ER - TY - JOUR ID - soton14880 UR - https://eprints.soton.ac.uk/14880/ IS - 1 A1 - Olabarria, C. Y1 - 2005/// N2 - Although the organization patterns of fauna in the deep sea have been broadly documented, most studies have focused on the megafauna. Bivalves represent about 10% of the deep-sea macrobenthic fauna, being the third taxon in abundance after polychaetes and peracarid crustaceans. This study, based on a large data set, examined the bathymetric distribution, patterns of zonation and diversity?depth trends of bivalves from the Porcupine Seabight and adjacent Abyssal Plain (NE Atlantic). A total of 131,334 individuals belonging to 76 species were collected between 500 and 4866 m. Most of the species showed broad depth ranges with some ranges extending over more than 3000 m. Furthermore, many species overlapped in their depth distributions. Patterns of zonation were not very strong and faunal change was gradual. Nevertheless, four bathymetric discontinuities, more or less clearly delimited, occurred at about 750, 1900, 2900 and 4100 m. These boundaries indicated five faunistic zones: (1) a zone above 750 m marking the change from shelf species to bathyal species; (2) a zone from 750 to 1900 m that corresponds to the upper and mid-bathyal zones taken together; (3) a lower bathyal zone from 1900 to 2900 m; (4) a transition zone from 2900 to 4100 m where the bathyal fauna meets and overlaps with the abyssal fauna and (5) a truly abyssal zone from approximately 4100?4900 m (the lower depth limit of this study), characterized by the presence of abyssal species with restricted depth ranges and a few specimens of some bathyal species with very broad distributions. The 4100 m boundary marked the lower limit of distribution of many bathyal species. There was a pattern of increasing diversity downslope from 500 to 1600 m, followed by a decrease to minimum values at about 2700 m. This drop in diversity was followed by an increase up to maximum values at 4100 m and then again, a fall to 4900 m (the lower depth limit in this study) JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 52 KW - bivalves KW - zonation patterns KW - vertical distribution KW - diversity KW - deep sea KW - NE Atlantic SN - 0967-0637 TI - Patterns of bathymetric zonation of bivalves in the Porcupine Seabight and adjacent Abyssal plain, NE Atlantic SP - 15 AV - none EP - 31 ER - TY - JOUR ID - soton2151 UR - https://eprints.soton.ac.uk/2151/ IS - 4 A1 - Olabarria, C. A1 - Thurston, M.H. Y1 - 2003/// N2 - Body size is a fundamental topic in ecology with important implications for community structure and biodiversity. Although there are numerous studies addressing patterns of geographic variation of body size in deep-sea benthos, results are conflicting. Thus geographic patterns of body size in deep-sea organisms remain poorly described. We analysed depth and latitudinal trends of body size in a species of gastropod, Troschelia berniciensis (King, 1846) from the eastern North Atlantic. We tested the hypotheses that (1) body size increases linearly with latitude and (2) body size increases with depth. Results partially supported the predictions. Firstly, there was a significant linear increase of body size with latitude, but this trend was weak. Secondly, body size decreased with depth. Environmental gradients that cause large-scale patterns of body-size variation in surface environments would have little effect on communities living at great depths. Latitudinal and depth clines may be produced by independent mechanisms that operate on different scales of time and space. JF - Marine Biology VL - 143 KW - GASTROPODS KW - TROSCHELIA BERNICIENSIS KW - BODY SIZE KW - BENTHIC COMMUNITIES KW - NORTH ATLANTIC OCEAN KW - ATLN KW - BIOGEOGRAPHY SN - 0025-3162 TI - Latitudinal and bathymetric trends in body size of the deep-sea gastropod Troschelia berniciensis (King) SP - 723 AV - none EP - 730 ER - TY - JOUR ID - soton385261 UR - https://eprints.soton.ac.uk/385261/ IS - 2 A1 - Orme, L.C. A1 - Reinhardt, L. A1 - Jones, R.T. A1 - Charman, D.J. A1 - Croudace, I. A1 - Dawson, A. A1 - Ellis, M. A1 - Barkwith, A. Y1 - 2016/02// N2 - Micro x-ray fluorescence (µXRF) core scanning is capable of measuring the elemental composition of lake sediment at sub-millimetre resolution, but bioturbation and physical mixing may degrade environmental signals at such fine scales. The aim of this research is to determine the maximum possible resolution at which meaningful environmental signals may be reconstructed from lake sediments using this method. Sediment from a coastal lake in the Outer Hebrides, Scotland, has been analysed using calibrated element measurements to reconstruct storminess since AD 200. We find that a Ca/K ratio in lake-core sediments reflects the presence of fine calcium carbonate shell fragments, a constituent of sand in the catchment that is washed and blown into the lake. Variations in this ratio are significantly correlated with instrumental records of precipitation and low pressures, suggesting it is a proxy for storminess. Furthermore, identification of a c. 60-year cycle supports a climatic influence on Ca/K, as this cycle is frequently identified in reconstructions of the North Atlantic Oscillation and North Atlantic sea-surface temperature. Comparison with weather records at different resolutions and spectral analysis indicate that µXRF data from Loch Hosta can be interpreted at sub-decadal resolutions (equivalent to core depth intervals of 3?5?mm in this location). Therefore, we suggest that sub-centimetre sampling using µXRF core scanning could be beneficial in producing environmental reconstructions in many lake settings where sediments are not varved. JF - The Holocene VL - 26 KW - lake sediment KW - late Holocene KW - North Atlantic Oscillation KW - storminess KW - XRF core scanner SN - 0959-6836 TI - Investigating the maximum resolution of XRF core scanners: A 1800 year storminess reconstruction from the Outer Hebrides SP - 235 AV - none EP - 247 ER - TY - JOUR ID - soton375540 UR - https://eprints.soton.ac.uk/375540/ IS - 1 A1 - Ostle, Clare A1 - Johnson, Martin A1 - Landschützer, Peter A1 - Schuster, Ute A1 - Hartman, Susan A1 - Hull, Tom A1 - Robinson, Carol Y1 - 2015/01// N2 - The magnitude of marine plankton net community production (NCP) is indicative of both the biologically driven exchange of carbon dioxide between the atmosphere and the surface ocean and the export of organic carbon from the surface ocean to the ocean interior. In this study the seasonal variability in the NCP of five biogeochemical regions in the North Atlantic was determined from measurements of surface water dissolved oxygen and dissolved inorganic carbon (DIC) sampled from a Volunteer Observing Ship (VOS). The magnitude of NCP derived from dissolved oxygen measurements (NCPinline image) was consistent with previous geochemical estimates of NCP in the North Atlantic, with an average annual NCPinline image of 9.5 ± 6.5 mmol O2 m?2 d?1. Annual NCPinline image did not vary significantly over 35° of latitude and was not significantly different from NCP derived from DIC measurements (NCPDIC). The relatively simple method described here is applicable to any VOS route on which surface water dissolved oxygen concentrations can be accurately measured, thus providing estimates of NCP at higher spatial and temporal resolution than currently achieved. JF - Global Biogeochemical Cycles VL - 29 KW - marine plankton KW - net community production KW - dissolved oxygen KW - dissolved inorganic carbon KW - Atlantic Ocean KW - Volunteer Observing Ship SN - 0886-6236 TI - Net community production in the North Atlantic Ocean derived from Volunteer Observing Ship data SP - 80 AV - public EP - 95 ER - TY - JOUR ID - soton365530 UR - https://eprints.soton.ac.uk/365530/ IS - 3 A1 - Painter, S.C. A1 - Patey, M.D. A1 - Tarran, G.A. A1 - Torres-Valdés, S. Y1 - 2014/06// N2 - We investigated the relationship between picoeukaryote phytoplankton (<2 ?m) and the deep layer of new production (NO3- uptake) in the nitracline of the eastern subtropical North Atlantic Ocean. Indices of NO3- uptake kinetics obtained within the lower 15% of the euphotic zone demonstrate that subsurface NO3- uptake maxima are coincident with localised peaks in maximum uptake rates (Vmax) and, crucially, with maximum picoeukaryote abundance. The mean rate of NO3- utilization at the nitracline is typically 10-fold higher than in surface waters despite much lower in-situ irradiances. These observations confirm a high affinity for NO3-, most likely by the resident picoeukaryote community, and we conservatively estimate mean cellular uptake rates of between 0.27 and 1.96 fmol NO3- cell-1 h-1. Greater scrutiny of the taxonomic composition of the picoeukaryote group is required to further understand this deep layer of new production and its importance for nitrogen cycling and export production given longstanding assumptions that picoplankton do not contribute directly to export fluxes. JF - Aquatic Microbial Ecology VL - 72 KW - Nitracline KW - Picoeukaryote KW - Nitrate uptake KW - Subtropical Atlantic Ocean SN - 0948-3055 TI - Picoeukaryote distribution in relation to nitrate uptake in the oceanic nitracline SP - 195 AV - public EP - 213 ER - TY - JOUR ID - soton63641 UR - http://www.int-res.com/abstracts/meps/v368/p53-63/ A1 - Painter, Stuart C. A1 - Sanders, Richard A1 - Waldron, Howard N. A1 - Lucas, Michael I. A1 - Torres-Valdes, Sinhue Y1 - 2008/09/25/ N2 - We investigate the distribution of urea and its uptake by phytoplankton during 3 meridional transects of the Atlantic Ocean between 50°N and 50° S. Significant relationships were identified between urea uptake and Prochlorococcus abundance (p < 0.01) in the northern subtropical Atlantic, where Prochlorococcus appears likely to dominate urea uptake, and between urea concentration and the <200 µm microplankton biomass fraction (p < 0.005) in the South Atlantic, which may be associated with the production of urea. These results suggest that the distribution of urea in the subtropical ocean may be controlled by regional imbalances between urea consumption and urea production. In parallel with these simple relationships significant spring-autumn seasonal changes in the distribution of urea were identified in southern subtropical and tropical latitudes. Urea was twice as abundant during local spring than during local autumn in the subtropical South Atlantic but 2.5 times more abundant in equatorial waters during the boreal autumn period. Euphotic zone integrated urea uptake rates also varied seasonally, being considerably higher in the North Atlantic temperate and subtropical latitudes during the boreal spring whilst in the subtropical South Atlantic urea uptake peaked in local autumn. JF - Marine Ecology Progress Series VL - 368 KW - Urea concentration KW - Prochlorococcus KW - Seasonal variability KW - Atlantic Meridional Transect · Urea uptake SN - 0171-8630 TI - Urea distribution and uptake in the Atlantic Ocean between 50° N and 50°S. SP - 53 AV - none EP - 63 ER - TY - JOUR ID - soton63859 UR - https://eprints.soton.ac.uk/63859/ IS - 1-2 A1 - Painter, Stuart C. A1 - Sanders, Richard A1 - Waldron, Howard N. A1 - Lucas, Michael I. A1 - Woodward, E. Malcolm S. A1 - Chamberlain, Katie Y1 - 2008/11// N2 - Measurements of nitrate (NO3?) uptake made using 15N tracers in the surface oligotrophic Atlantic Ocean on three meridional transects are compared. Cruises occurred over the course of 1 year (AMT12 May?June 2003, AMT13 September?October 2003, AMT14 April?May 2004). Significant differences (p < 0.001) in mean daily integrated rates of NO3? uptake are identified between the two boreal spring cruises (AMT12 and AMT14) over the entire tropical and subtropical ocean (~ 40°S?40°N) which is caused by widespread increases in ambient NO3? concentrations in the surface ocean. The increase in NO3? concentration is small, typically between 5?10 nmol L? 1 but promotes a significant uptake response. Carbon fixation rates meanwhile show small increases during AMT14 relative to AMT12 in the equatorial region but not in gyral latitudes suggesting that the increased NO3? did not generally increase production rates but may instead have invoked a shift in the preferred form of nitrogen used by photosynthetic organisms. A greater proportion of the observed production might therefore have been available for export during 2004 compared to 2003. Observed intercruise differences in the separation distance between the base of the mixed layer and the nitracline suggest that this may be an important physical consideration which allows for greater nutrient transfer during periods of smaller separation, as was the case during 2004, and that this represents a potential control on export production.
JF - Journal of Marine Systems VL - 74 KW - New production KW - Nitrate uptake KW - Subtropical gyre KW - Atlantic Meridional Transect KW - Atlantic Ocean SN - 0924-7963 TI - Nitrate uptake along repeat meridional transects of the Atlantic Ocean SP - 227 AV - none EP - 240 ER - TY - JOUR N1 - Funding Information: This project was supported by the Australian Research Council (grant no. DE200100907 and DP130104156). P. Panaretos was supported by a UNSW Summer Vacation Research Scholarship. P.G.A and G.J are funded through a UK Research and Innovation Future Leaders Fellowship (MR/S035478/1). We thank Rebecca Smith for providing constructive comments on an earlier version of this manuscript. We thank the Falkland Islands Government for permission to undertake sampling on the island (permit number: R07/2011). Funding Information: This project was supported by the Australian Research Council (grant no. DE200100907 and DP130104156 ). P. Panaretos was supported by a UNSW Summer Vacation Research Scholarship. P.G.A and G.J are funded through a UK Research and Innovation Future Leaders Fellowship ( MR/S035478/1 ). We thank Rebecca Smith for providing constructive comments on an earlier version of this manuscript. We thank the Falkland Islands Government for permission to undertake sampling on the island (permit number: R07/2011). Publisher Copyright: © 2021 ID - soton476220 UR - https://eprints.soton.ac.uk/476220/ IS - 8 A1 - Panaretos, Panayiotis A1 - Albert, Paul G. A1 - Thomas, Zoë A. A1 - Turney, Chris S.M. A1 - Stern, Charles R. A1 - Jones, G. A1 - Williams, Alan N. A1 - Smith, Victoria C. A1 - Hogg, Alan G. A1 - Manning, Christina J. Y1 - 2021/08/15/ N2 - Cryptotephra deposits (microscopic volcanic ash) are important geochronological tools that can be used to synchronize records of past environmental change. Here we report a distal cryptotephra from a Holocene peat sequence (Canopus Hill) in the Falkland Islands, in the South Atlantic. Using geochemical analysis (major- and trace-element) of individual volcanic glass shards, we provide a robust correlation between this cryptotephra and the large mid-Holocene explosive eruption of Mt. Hudson in Patagonia, Chile (H2; ?3.9 ka cal BP). The occurrence of H2 as a cryptotephra in the Falkland Islands significantly increases the known distribution of this marker horizon to more than 1200 km from the volcano, a threefold increase of its previous known extent. A high-resolution radiocarbon chronology, based on terrestrial plant macrofossils, dates the H2 tephra to 4265 ± 65 cal yr BP, suggesting that the eruption may have occurred slightly earlier than previously reported. The refined age and new geochemical reference dataset will facilitate the identification of the H2 tephra in other distal locations. The high concentration of glass shards in our peat sequence indicates that the H2 tephra may extend well beyond the Falkland Islands and we recommend future studies search for its presence across the sub-Antarctic islands and Antarctic Peninsula as a potentially useful chronological marker. JF - Quaternary Science Reviews VL - 266 KW - Antarctic KW - Cryptotephra KW - Hudson KW - Patagonia KW - South America KW - South Atlantic KW - Southern Ocean KW - Southern volcanic zone KW - Tephrochronology SN - 0277-3791 TI - Distal ash fall from the mid-Holocene eruption of Mount Hudson (H2) discovered in the Falkland Islands: New possibilities for Southern Hemisphere archive synchronisation AV - none ER - TY - JOUR ID - soton44170 UR - https://eprints.soton.ac.uk/44170/ IS - 3 A1 - Papadopoulos, A. A1 - Tsimplis, M.N. Y1 - 2006/// N2 - Coastal sea level measured from tide gauges exhibits coherent variability at interannual and decadal scales. We investigate sea-level variability of large geographic areas using annual mean sea-level values obtained from the longest available records of coastal observations. Eight sea-level regional indices are constructed for the Atlantic and the Pacific Ocean basins. High coherency of sea-level variability at the decadal timescales between different oceanic regions is observed. The role of large-scale atmospheric forcing is then examined by comparison with the El Niño?Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). Strong correlation between the NAO and the second empirical orthogonal function (EOF) of the northwest Atlantic data set was observed. The second EOF is also significantly correlated with the latitudinal position of Gulf Stream and the Arctic Oscillation (AO). Sea-level changes in the northeast Atlantic are driven by the NAO. Correlation with the AO was also observed. In the Pacific Ocean, ENSO dominates sea-level variability along the eastern and southwest sides of the basin. ENSO signatures appear also in the southwest Atlantic, indicating teleconnection patterns. It is proposed that ENSO-related variability in this region is forced through the Pacific?South American teleconnection mechanism. The correlation between southwest Atlantic sea level and ENSO increased after 1980. Sea-level variability on decadal scales in the northwest Pacific region is influenced by the Pacific Decadal Oscillation.
JF - Journal of Coastal Research VL - 22 KW - teleconnections KW - indices KW - regional sea level KW - North Atlantic Oscillation KW - El Niño?Southern Oscillation KW - Southern Oscillation Index KW - Arctic Oscillation KW - Pacific Decadal Oscillation SN - 0749-0208 TI - Coherent coastal sea level variability at inter-decadal and inter-annual scales from tide gauges SP - 625 AV - none EP - 639 ER - TY - JOUR N1 - Funding Information: This research used samples provided by the Integrated Ocean Drilling Program (IODP). We thank James Channell, the shipboard party of IODP Expedition 303, and H. Kuhlmann for their help at the Bremen Core Repository. We also thank two anonymous reviewers for their constructive comments that helped us to improve our manuscript significantly. R.L.P. acknowledges funding from a University of Exeter International Excellence Scholarship. P.A.W. acknowledges support from Natural Environment Research Council (grant number NE/K014137/1 ) and P.A.W. and G.L.F. acknowledge the Royal Society ( Wolfson Merit Awards ). Funding Information: This research used samples provided by the Integrated Ocean Drilling Program (IODP). We thank James Channell, the shipboard party of IODP Expedition 303, and H. Kuhlmann for their help at the Bremen Core Repository. We also thank two anonymous reviewers for their constructive comments that helped us to improve our manuscript significantly. R.L.P. acknowledges funding from a University of Exeter International Excellence Scholarship. P.A.W. acknowledges support from Natural Environment Research Council (grant number NE/K014137/1) and P.A.W. and G.L.F. acknowledge the Royal Society (Wolfson Merit Awards). Publisher Copyright: © 2023 The Author(s) ID - soton479430 UR - https://eprints.soton.ac.uk/479430/ A1 - Parker, Rebecca L. A1 - Foster, Gavin A1 - Gutjahr, Marcus A1 - Wilson, Paul A1 - Obrochta, Stephen P. A1 - Fagel, Natalie A1 - Cooper, Matthew J. A1 - Michalik, Agnes A1 - Milton, J. Andy A1 - Bailey, Ian Y1 - 2023/09/15/ N2 - Termination (T) 5, ?424 ka, involved the biggest deglaciation of land-ice mass during the Quaternary. Warming and ice-sheet retreat during T5 led to an exceptionally long period of interglacial warmth known as Marine Isotope Stage (MIS) 11, ?424?395 ka. A detailed understanding of the history of continental ice-sheet decay during T5 is required to disentangle regional contributions of ice-sheet retreat to sea-level rise (that range between ?1 and 13 m above present day) and to correct it for glacio-isostatic adjustments (GIA). Yet little is known about the timing and magnitude of retreat during this time of the volumetrically most important continental ice sheet in the Northern Hemisphere, the Laurentide Ice Sheet (LIS). Here we present new authigenic Fe-Mn oxyhydroxide-derived high-resolution records of Pb isotope data and associated rare earth element profiles for samples spanning T5 from Labrador Sea IODP Site U1302/3. These records feature astronomically-paced radiogenic Pb isotope excursions that track increases in chemical weathering of North American bedrock and freshwater routing to the Labrador Sea via Hudson Straits associated with LIS retreat. Our records show that LIS retreat during T5 began 429. 2 ± 7.9 ka (2?) and likely occurred over a longer timescale (by ?10 to 5 kyr) than that observed for T2 and T1. They also show that Hudson Bay Ice Saddle collapse (and therefore LIS break-up) occurred ?419 ± 4.7 ka (2?), around the same time as best estimates of southern Greenland deglaciation, but ?12 kyr before LIS deglaciation and the sea-level high-stand associated with the latter half of MIS 11 likely occurred. Our findings therefore highlight that ice-mass loss on North America likely played an important role in the seemingly protracted nature of T5 sea-level rise. A comparison of the deglaciation histories of the LIS and the southern Greenland Ice Sheet during T5, T2 and T1 also demonstrates that the well-constrained history of regional ice-sheet retreat during T1 is not always applicable as a template for older late Pleistocene terminations in GIA modelling. JF - Earth and Planetary Science Letters VL - 618 KW - chemical weathering KW - interglacial sea-level KW - Laurentide Ice Sheet KW - MIS 11 KW - North Atlantic KW - Pb isotope SN - 0012-821X TI - The history of ice-sheet retreat on North America during Termination 5: implications for the origin of the sea-level highstand during interglacial stage 11 AV - public EP - 14 ER - TY - JOUR N1 - Funding Information: This research uses samples provided by the IODP , which is sponsored by the U.S. National Science Foundation and participating countries under management of Joint Oceanographic Institutions, Inc. We thank the shipboard party of IODP Expedition 303 and A. Wuelbers, W. Hale and H. Kuhlmann for their help at the Bremen Core Repository and Megan Spencer for laboratory support in Southampton. R.L.P. acknowledges funding from a University of Exeter International Excellence Scholarship. P.A.W. acknowledges support from Natural Environment Research Council (grant number NE/K014137/1) and the Royal Society (Wolfson Merit Award). We thank Antje Voelker for editorial handling and Nathalie Fagel and Alberto Reyes for constructive feedback at the review stage that helped significantly to improve the final version of this manuscript. We are also grateful to Nathalie Fagel for providing us with access to her compilations of circum-North Atlantic terrane Pb isotope data. Publisher Copyright: © 2022 The Authors ID - soton457733 UR - https://eprints.soton.ac.uk/457733/ IS - 107564 A1 - Parker, Rebecca L. A1 - Foster, Gavin L. A1 - Gutjahr, Marcus A1 - Wilson, Paul A. A1 - Littler, Kate L. A1 - Cooper, Matthew J. A1 - Michalik, Agnes A1 - Milton, James A. A1 - Crocket, Kirsty C. A1 - Bailey, Ian Y1 - 2022/07/01/ N2 - Understanding the history of continental ice-sheet growth on North America, and in particular that of the Laurentide Ice Sheet (LIS), is important for palaeoclimate and sea-level reconstructions. Information on ice-sheet extent pre-dating the Last Glacial Maximum (LGM) is heavily reliant, though, on the outputs of numerical models underpinned by scant geological data. Important aspects of LIS history that remain unresolved include the timing of its collapse during Termination 2, the first time that it expanded significantly during the Last Glacial Cycle, and whether its volume was significantly reduced during marine isotope stage (MIS) 3. To address these issues and more, we present authigenic iron-manganese (Fe?Mn) oxyhydroxide-derived high-resolution records of Pb isotope data and associated rare earth element profiles for samples spanning the past ?130 kyr from northwest North Atlantic Labrador Sea, IODP Site U1302/3. We use these new data to track chemical weathering intensity and solute flux to the Labrador Sea associated with LIS extent on the adjacent highly radiogenic (high Pb isotope composition) North American Superior Province (SP) craton since the Penultimate Glacial Maximum (PGM). Our new records show that relatively high (radiogenic) values characterise warm marine isotope stages (MIS) 5, 3 and 1 and the lowest (most unradiogenic) values occurred during cold stages MIS 6, 4 and 2. The radiogenic Pb isotope excursion associated with Termination 2 is short-lived relative to the one documented for Termination 1, suggesting that LIS retreat during the PGM was relatively fast compared to the LGM and that its collapse during the last interglacial occurred ?125 ka. Highly radiogenic inputs to the Labrador Sea during MIS 5d-a, ?116?71 ka, most likely reflect a spin-up in Labrador Current vigour, incipient glaciation and renewed glacial erosion of high grounds of the eastern SP craton by localised wet-based ice-caps. A large decrease in Pb isotope values towards unradiogenic LGM-like compositions between ?75?65 ka across the MIS 5/4 transition likely reflects a slow-down in Labrador Current vigour, an increase in subaerial deposition of aeolian dust and a significant advance of the LIS across Hudson Bay caused a strong reduction or even abandonment of Pb sourcing from the SP. The relatively radiogenic Pb isotope composition of bottom-waters bathing our study site during MIS 3, 57?29 ka, is unlikely to support a recently proposed major reduction in LIS extent for this time. Instead, we argue these values are better explained by southern Greenland Ice Sheet retreat, increased chemical weathering of the Ketelidian Mobile Belt and subsequent Pb runoff from Greenland. JF - Quaternary Science Reviews VL - 287 KW - Chemical weathering KW - Continental runoff KW - Fe?Mn oxyhydroxides KW - Labrador Current KW - Last Glacial Cycle KW - North Atlantic KW - Paleoceanography KW - Quaternary KW - Rare earth elements SN - 0277-3791 TI - Laurentide Ice Sheet extent over the last 130 thousand years traced by the Pb isotope signature of weathering inputs to the Labrador Sea AV - public ER - TY - JOUR ID - soton8887 UR - https://eprints.soton.ac.uk/8887/ IS - 3/4 A1 - Parson, L. A1 - Gracia, E. A1 - Coller, D. A1 - German, C. A1 - Needham, D. Y1 - 2000/// N2 - Deep-tow sidescan sonar data acquired along 240 km of the Mid-Atlantic Ridge (MAR) between 35°40?N and 38°N have been combined with new bathymetric compilations and used to establish the recent tectonic and volcanic history of six second-order segments and their bounding non-transform offsets (NTOs). The segments show a range of volcanic and tectonic types, but in general the northernmost segments (i.e. those with greater influence from the Azorean hotspot) are shallower and more volcanically robust than those to the south, with hydrothermal activity in segment centres (for example, Menez Gwen and Lucky Strike). Nonetheless, this generalisation requires some modification due to temporal variations in the balance between magmatic supply and tectonic dismemberment. The NTOs are broad right-stepping discontinuities, locally up to 25 km wide, and accommodate offsets between 10 and 50 km. The discontinuities are mostly sediment-floored, and link the spreading segment tips with a range of structures. These include locally dense arrays of en echelon extensional normal faults, short lengths of linear strike?slip fault strands occasionally cutting basement blocks apparently stranded within the offsets. Basement blocks within the offsets are cross-cut by complexes of intersecting faults, suggesting that deformation is distributed across the zone. The pervasive faulting taking place at the NTOs favours fluid circulation and associated hydrothermal activity, as at the Rainbow Site at 36°17?N. JF - Earth and Planetary Science Letters VL - 178 KW - MID ATLANTIC RIDGE KW - VOLCANISM KW - TECTONICS KW - FAULTS KW - TOBI KW - SIDE SCAN SONAR KW - AMAR KW - MENEZ GWEN KW - LUCKY STRIKE KW - FAMOUS SN - 0012-821X TI - Second-order segmentation; the relationship between volcanism and tectonism at the MAR, 38N-35 40N SP - 231 AV - none EP - 251 ER - TY - JOUR ID - soton452245 UR - https://eprints.soton.ac.uk/452245/ IS - 7 A1 - Paul, Helen N2 - When the South Sea Bubble burst in 1720, there was an outpouring of critical commentary. This took a variety of forms but centred around common themes of fraud and ruin. Three hundred years later, there is a renewed focus on the horrors of the slave trade. In addition, slaving companies needed the help of the Royal Navy and the navy used impressment. Forced labour was an essential part of the Bubble story but is often erased from it or merely mentioned in passing. Complaints by wealthy people about their losses have drowned out the voices of the enslaved. VL - 102 TI - The South Sea Bubble and the erasure of slavery and impressment AV - public EP - 900 N1 - Funding Information: I would like to thank Giovanni Iamartino and Nicholas Brownlees for inviting me to contribute to this special issue. I would also like to thank the two anonymous reviewers and the editor. Publisher Copyright: © 2021 University of Southampton. Published by Informa UK Limited, trading as Taylor & Francis Group. Y1 - 2021/11/02/ JF - English Studies KW - Atlantic history KW - Royal African Company KW - Royal Navy KW - South Sea Bubble KW - forced labour KW - slavery SN - 1744-4217 SP - 888 ER - TY - JOUR ID - soton8726 UR - https://eprints.soton.ac.uk/8726/ IS - 3 A1 - Perez, F.F. A1 - Pollard, R.T. A1 - Read, J.F. A1 - Valencia, V. A1 - Cabanas, J.M. A1 - Rios, A.F. Y1 - 2000/// JF - Scientia Marina VL - 64 KW - DECADAL VARIABILITY KW - THERMOHALINE STRUCTURES KW - NORTH ATLANTIC OSCILLATION SN - 0214-8358 TI - Climatological coupling of the thermohaline decadal changes in Central Water of the eastern North Atlantic SP - 347 AV - none EP - 353 ER - TY - JOUR ID - soton44240 UR - https://eprints.soton.ac.uk/44240/ IS - 10 A1 - Perez, V. A1 - Fernandez, E. A1 - Maranon, E. A1 - Moran, X.A.G. A1 - Zubkov, M.V. Y1 - 2006/// N2 - Ninety-four stations were sampled in the Atlantic subtropical gyres during 10 cruises carried out between 1995 and 2001, mainly in boreal spring and autumn. Chlorophyll a (Chl-a) and primary production were measured during all cruises, and phytoplankton biomass was estimated in part of them. Picoplankton (<2 ?m) represented >60% of total Chl-a concentration measured at the surface, and their contribution to this variable increased with depth. Phytoplankton carbon concentrations were higher in the upper metres of the water column, whereas Chl-a showed a deep maximum (DCM). At each station, the water column was divided into the upper mixed layer (ML) and the DCM layer (DCML). The boundary between the two layers was calculated as the depth where Chl-a concentration was 50% of the maximum Chl-a concentration. On average DCML extends from 67 to 126 m depth. Carbon to Chl-a (C:Chl-a) ratios were used to estimate phytoplankton carbon content from Chl-a in order to obtain a large phytoplankton carbon dataset. Total C:Chl-a ratios averaged (±s.e.) 103±7 (n=22) in the ML and 24±4 (n=12) in the DCML and were higher in larger cells than in picoplankton. Using these ratios and primary production measurements, we derived mean specific growth rates of 0.17±0.01 d?1 (n=173) in the ML and 0.20±0.01 d?1 (n=165) in the DCML although the differences were not significant (t-test, p>0.05). Our results suggest a moderate contribution of the DCML (43%) to both phytoplankton biomass and primary production in the Atlantic subtropical gyres.
JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 53 KW - phytoplankton KW - biomass KW - primary production KW - growth KW - Atlantic subtropical gyres KW - AMT SN - 0967-0637 TI - Vertical distribution of phytoplankton biomass, production and growth in the Atlantic subtropical gyres SP - 1616 AV - none EP - 1634 ER - TY - JOUR ID - soton342786 UR - https://eprints.soton.ac.uk/342786/ IS - 3-4 A1 - Persechino, A. A1 - Marsh, R. A1 - Sinha, B. A1 - Megann, A.P. A1 - Blaker, A.T. A1 - New, A.L. Y1 - 2012/// N2 - A wide range of statistical tools is used to investigate the decadal variability of the Atlantic Meridional Overturning Circulation (AMOC) and associated key variables in a climate model (CHIME, Coupled Hadley-Isopycnic Model Experiment), which features a novel ocean component. CHIME is as similar as possible to the 3rd Hadley Centre Coupled Model (HadCM3) with the important exception that its ocean component is based on a hybrid vertical coordinate. Power spectral analysis reveals enhanced AMOC variability for periods in the range 15?30 years. Strong AMOC conditions are associated with: (1) a Sea Surface Temperature (SST) anomaly pattern reminiscent of the Atlantic Multi-decadal Oscillation (AMO) response, but associated with variations in a northern tropical-subtropical gradient; (2) a Surface Air Temperature anomaly pattern closely linked to SST; (3) a positive North Atlantic Oscillation (NAO)-like pattern; (4) a northward shift of the Intertropical Convergence Zone. The primary mode of AMOC variability is associated with decadal changes in the Labrador Sea and the Greenland Iceland Norwegian (GIN) Seas, in both cases linked to the tropical activity about 15 years earlier. These decadal changes are controlled by the low-frequency NAO that may be associated with a rapid atmospheric teleconnection from the tropics to the extratropics. Poleward advection of salinity anomalies in the mixed layer also leads to AMOC changes that are linked to processes in the Labrador Sea. A secondary mode of AMOC variability is associated with interannual changes in the Labrador and GIN Seas, through the impact of the NAO on local surface density. JF - Climate Dynamics VL - 39 KW - Atlantic Meridional Overturning Circulation KW - North Atlantic Oscillation KW - Coupled climate model KW - Isopycnal KW - Decadal variability SN - 0930-7575 TI - Decadal-timescale changes of the Atlantic overturning circulation and climate in a coupled climate model with a hybrid-coordinate ocean component SP - 1021 AV - none EP - 1042 ER - TY - JOUR ID - soton353518 UR - https://eprints.soton.ac.uk/353518/ IS - 9-10 A1 - Persechino, A. A1 - Mignot, J. A1 - Swingedouw, D. A1 - Labetoulle, S. A1 - Guilyardi, E. Y1 - 2013/05// N2 - This study explores the decadal potential predictability of the Atlantic Meridional Overturning Circulation (AMOC) as represented in the IPSL-CM5A-LR model, along with the predictability of associated oceanic and atmospheric fields. Using a 1000-year control run, we analyze the prognostic potential predictability (PPP) of the AMOC through ensembles of simulations with perturbed initial conditions. Based on a measure of the ensemble spread, the modelled AMOC has an average predictive skill of 8 years, with some degree of dependence on the AMOC initial state. Diagnostic potential predictability of surface temperature and precipitation is also identified in the control run and compared to the PPP. Both approaches clearly bring out the same regions exhibiting the highest predictive skill. Generally, surface temperature has the highest skill up to 2 decades in the far North Atlantic ocean. There are also weak signals over a few oceanic areas in the tropics and subtropics. Predictability over land is restricted to the coastal areas bordering oceanic predictable regions. Potential predictability at interannual and longer timescales is largely absent for precipitation in spite of weak signals identified mainly in the Nordic Seas. Regions of weak signals show some dependence on AMOC initial state. All the identified regions are closely linked to decadal AMOC fluctuations suggesting that the potential predictability of climate arises from the mechanisms controlling these fluctuations. Evidence for dependence on AMOC initial state also suggests that studying skills from case studies may prove more useful to understand predictability mechanisms than computing average skill from numerous start dates. JF - Climate Dynamics VL - 40 KW - Decadal climate predictability KW - Atlantic meridional overturning circulation KW - Diagnostic and prognostic potential predictability KW - Ocean and climate dynamics SN - 0930-7575 TI - Decadal predictability of the Atlantic meridional overturning circulation and climate in the IPSL-CM5A-LR model SP - 2359 AV - none EP - 2380 ER - TY - JOUR N1 - Actually deposited by Jane Conquer ID - soton51293 UR - http://www.agu.org/journals/pa/pa0801/2007PA001517/ IS - 1 A1 - Petrizzo, M.R. A1 - Huber, B.T. A1 - Wilson, P.A. A1 - MacLeod, K.G. Y1 - 2008/03// N2 - A late Albian?early Cenomanian record (~103.3 to 99.0 Ma), including organic-rich deposits and a ?13C increase associated with oceanic anoxic event 1d (OAE 1d), is described from Ocean Drilling Program sites 1050 and 1052 in the subtropical Atlantic. Foraminifera are well preserved at these sites. Paleotemperatures estimated from benthic ?18O values average ~14°C for middle bathyal Site 1050 and ~17°C for upper bathyal Site 1052, whereas surface temperatures are estimated to have ranged from 26°C to 31°C at both sites. Among planktonic foraminifera, there is a steady balance of speciation and extinction with no discrete time of major faunal turnover. OAE 1d is recognized on the basis of a 1.2? ?13C increase (~100.0?99.6 Ma), which is similar in age and magnitude to ?13C excursions documented in the North Atlantic and western Tethys. Organic-rich ?black shales? are present throughout the studied interval at both sites. However, deposition of individual black shale beds was not synchronous between sites, and most of the black shale was deposited before the OAE 1d ?13C increase. A similar pattern is observed at the other sites where OAE 1d has been recognized indicating that the site(s) of excess organic carbon burial that could have caused the ?13C increase has (have) yet to be found. Our findings add weight to the view that OAEs should be chemostratigraphically (?13C) rather than lithostratigraphically defined. JF - Paleoceanography VL - 23 KW - micropaleontology KW - stable isotope KW - paleoceanography KW - Atlantic Ocean KW - Cretace SN - 0883-8305 TI - Late Albian paleoceanography of the western subtropical North Atlantic AV - none ER - TY - JOUR ID - soton348313 UR - https://eprints.soton.ac.uk/348313/ A1 - Pidcock, Rosalind A1 - Martin, Adrian A1 - Allen, John A1 - Painter, Stuart C. A1 - Smeed, David Y1 - 2013/02// N2 - This paper quantitatively assesses the mesoscale spatial variability in vertical velocity associated with an open ocean eddy dipole. High-resolution, in situ data were collected during a research cruise aboard the NERC research ship RRS Discovery to the Iceland Basin in July/August 2007. A quasi-synoptic SeaSoar spatial survey revealed a southeastward flowing jet with counter-rotating eddies on either side. The anti-cyclonic component was identified as a mode water eddy, characterised by a homogenous core (?35.5 psu and 12 °C) centred at a depth of ?600 m. Vertical velocities were calculated by inverting the quasi-geostrophic (QG) Omega equation at each point in a three-dimensional grid encompassing the dipole. The strongest vertical velocities (up to 5 m day?1) were found primarily in the central jet between the eddies, as fast flowing water was forced over raised isopycnals associated with the large potential vorticity anomaly of the mode water eddy. Weaker upward (downward) vertical velocity was diagnosed ahead of the cyclonic (mode water) eddy in the direction of propagation, reaching 0.5 m day?1 (2.5 m day?1) at the depth of maximum potential vorticity (PV) anomaly. The results demonstrate that the mesoscale velocity field cannot be accurately reconstructed from analysis of individual isolated eddy features and that detailed three-dimensional maps of potential vorticity are required to quantify the cumulative effects of their interactions. An examination of potential sources of error associated with the vertical velocity diagnosis is presented, including sampling strategy, quasi-synopticity, sensitivity to interpolation length scale and the unquantified effect of lower boundary conditions. The first three of these errors are quantified as potentially reaching 50%, ?20% and ?25% of the calculated vertical velocity, respectively, indicating a potential margin of error in the vertical velocity diagnosis of order one. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 72 KW - Mesoscale KW - Omega equation KW - Potential vorticity KW - Vertical velocity KW - Dipole KW - North Atlantic SN - 0967-0637 TI - The spatial variability of vertical velocity in an Iceland basin eddy dipole SP - 121 AV - none EP - 140 ER - TY - JOUR ID - soton8942 UR - http://www.int-res.com/abstracts/meps/v198/p171-179.html A1 - Pond, D.W. A1 - Gebruk, A. A1 - Southward, E.C. A1 - Southward, A.J. A1 - Fallick, A.E. A1 - Bell, M.V. A1 - Sargent, J.R. Y1 - 2000/// N2 - Lipid and stable carbon isotope analyses of Rimicaris exoculata, the dominant bresilioid shrimp found at the MAR (Mid-Atlantic Ridge) vent sites, have indicated that these animals possess a highly unusual storage lipid composition. The dominant neutral lipid classes, triacylglycerols and wax esters, contained very high levels of polyunsaturated fatty acids (PUFA, up to 89% of neutral lipid fatty acids). Gas chromatography isotope ratio mass spectrometry (GC-IRMS) analysis of the PUFA from neutral lipid gave d13C (v-PDB) values of -17.6 to -27.1[per thou], which is within the range expected for a photosynthetic origin for these compounds. Fatty acid analyses of bacterial/detrital material collected from the vent sites contained only very low amounts of PUFA. It is clear from these findings that R. exoculata has evolved a highly specialized lipid metabolism which allows it to store substantial amounts of PUFA during its early planktotrophic life stages. These PUFA reserves will be subsequently mobilized to enable growth and maturation of the shrimp on return to a suitable vent site and are therefore an important factor allowing R. exoculata to inhabit deep sea vent ecosystems. JF - Marine Ecology Progress Series VL - 198 KW - FATTY ACIDS KW - LIPIDS KW - SHRIMPS KW - MID ATLANTIC RIDGE KW - HYDROTHERMAL COMMUNITIES KW - BIOGEOCHEMISTRY SN - 0171-8630 TI - Unusual fatty acid composition of storage lipids in the bresilioid shrimp Rimicaris exoculata couples the photic zone with MAR hydrothermal vent sites SP - 171 AV - none EP - 179 ER - TY - JOUR ID - soton49776 UR - https://eprints.soton.ac.uk/49776/ IS - 5-7 A1 - Poulton, A.J. A1 - Adey, T.R. A1 - Balch, W.M. A1 - Holligan, P. Y1 - 2007/03// N2 - Recent measurements of surface coccolithophore calcification from the Atlantic Ocean (50°N?50°S) are compared to similar measurements from other oceanic settings. By combining the different data sets of surface measurements, we examine general and regional patterns of calcification relative to organic carbon production (photosynthesis) and other characteristics of the phytoplankton community. Generally, surface calcification and photosynthesis are positively correlated, although the strength of the relationship differs between biogeochemical provinces. Relationships between surface calcification, chlorophyll-a and calcite concentrations are also statistically significant, although again there is considerable regional variability. Such variability appears unrelated to phytoplankton community composition or hydrographic conditions, and may instead reflect variations in coccolithophore physiology. The contribution of inorganic carbon fixation (calcification) to total carbon fixation (calcification plus photosynthesis) is 1?10%, and we estimate a similar contribution from coccolithophores to total organic carbon fixation. However, these contributions vary between biogeochemical provinces, and occasionally coccolithophores may account for >20% of total carbon fixation in unproductive central subtropical gyres. Combining surface calcification and photosynthetic rates with standing stocks of calcite, particulate organic carbon, and estimated phytoplankton carbon allows us to examine the fates of these three carbon pools. The relative turnover times vary between different biogeochemical provinces, with no clear relationship to the overall productivity or phytoplankton community structure found in each province. Rather, interaction between coccolithophore physiology (coccolith production and detachment rates), species diversity (cell size), and food web dynamics (grazer ecology) may control the composition and turnover times of calcite particles in the upper ocean.
JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 54 KW - Calcification KW - Photosynthesis KW - Calcite KW - Coccolithophores KW - Ballast KW - Atlantic Meridional Transect SN - 0967-0645 TI - Relating coccolithophore calcification rates to phytoplankton community dynamics: regional differences and implications for carbon export SP - 538 AV - none EP - 557 ER - TY - JOUR ID - soton43985 UR - https://eprints.soton.ac.uk/43985/ IS - 14-16 A1 - Poulton, A.J. A1 - Holligan, P.M. A1 - Hickman, A. A1 - Kim, Y.N. A1 - Adey, T.R. A1 - Stinchcombe, M.C. A1 - Holeton, C. A1 - Root, S. A1 - Woodward, E.M.S. Y1 - 2006/// N2 - We have made daily measurements of phytoplankton pigments, size-fractionated (<2 and >2-?m) carbon fixation and chlorophyll-a concentration during four Atlantic Meridional Transect (AMT) cruises in 2003?04. Surface rates of carbon fixation ranged from <0.2-mmol C m?3 d?1 in the subtropical gyres to 0.2?0.5-mmol C m?3 d?1 in the tropical equatorial Atlantic. Significant intercruise variability was restricted to the subtropical gyres, with higher chlorophyll-a concentrations and carbon fixation in the subsurface chlorophyll maximum during spring in either hemisphere. In surface waters, although picoplankton (<2-?m) represented the dominant fraction in terms of both carbon fixation (50?70%) and chlorophyll-a (80?90%), nanoplankton (>2-?m) contributions to total carbon fixation (30?50%) were higher than to total chlorophyll-a (10?20%). However, in the subsurface chlorophyll maximum picoplankton dominated both carbon fixation (70?90%) and chlorophyll-a (70?90%). Thus, in surface waters chlorophyll-normalised carbon fixation was 2?3 times higher for nanoplankton and differences in picoplankton and nanoplankton carbon to chlorophyll-a ratios may lead to either higher or similar growth rates. These low chlorophyll-normalised carbon fixation rates for picoplankton may also reflect losses of fixed carbon (cell leakage or respiration), decreases in photosynthetic efficiency, grazing losses during the incubations, or some combination of all these. Comparison of nitrate concentrations in the subsurface chlorophyll maximum with estimates of those required to support the observed rates of carbon fixation (assuming Redfield stoichiometry) indicate that primary production in the chlorophyll maximum may be light rather than nutrient limited.

JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 53 KW - phytoplankton KW - carbon fixation KW - picoplankton KW - nanoplankton KW - chlorophyll-a KW - Atlantic Meridional Transect SN - 0967-0645 TI - Phytoplankton carbon fixation, chlorophyll-biomass and diagnostic pigments in the Atlantic Ocean SP - 1593 AV - none EP - 1610 ER - TY - JOUR ID - soton42349 UR - https://eprints.soton.ac.uk/42349/ IS - 4 A1 - Poulton, A.J. A1 - Sanders, R. A1 - Holligan, P.M. A1 - Stinchcombe, M.C. A1 - Adey, T.R. A1 - Brown, L. A1 - Chamberlain, K. Y1 - 2006/10/13/ N2 - Organic carbon fluxes to the deep ocean may be enhanced by association with ballast mineral material such as calcite and opal. We made simultaneous measurements of the upper ocean production of calcite (calcification), opal (silicification) and organic carbon (photosynthesis) at 14 stations between 42°S and 49°N in the Atlantic Ocean. These measurements confirm the light-dependency of calcification and photosynthesis, and the substrate dependency of silicification. We estimate that mineralizing phytoplankton represent ~5?20% of organic carbon fixation, with similar contributions from both coccolithophores and diatoms. Estimates of average turnover times for calcite and phytoplankton carbon are ~3 days, indicative of their relatively labile nature. By comparison, average turnover times for opal and particulate organic carbon are ~10 days. Rapid turnover of calcite suggests an important role for the plankton community in removing calcite from the upper ocean. Comparison of our surface production rates to sediment trap data confirms that ~70% of calcite is dissolved in the upper 2?3 km, and only a small proportion of total organic carbon (<2%) reaches the deep ocean. JF - Global Biogeochemical Cycles VL - 20 KW - calcification KW - silicic acid concentrations KW - atlantic meridional transect SN - 0886-6236 TI - Phytoplankton mineralization in the tropical and subtropical Atlantic Ocean SP - GB4002 AV - none EP - [10pp] ER - TY - JOUR ID - soton352181 UR - https://eprints.soton.ac.uk/352181/ IS - 5-6 A1 - Priede, Imants G. A1 - Billett, David S.M. A1 - Brierley, Andrew S. A1 - Hoelzel, A. Rus A1 - Inall, Mark A1 - Miller, Peter I. Y1 - 2013/// N2 - The ECOMAR project conducted 4 cruises to the Mid-Atlantic Ridge (MAR) in the summer months of the years 2007?2010 making repeat visits to 4 stations at 2500 m depth on the flanks of the MAR; a pair of northern stations at 54°N and southern stations at 49°N. Swath bathymetry surveys across the ridge revealed a pattern of sediment-covered flat terraces parallel to the axis of the MAR with intervening steep rocky slopes. Benthic fauna were sampled by otter trawl, megacorer and a suite of tools carried by the ROV Isis including push cores, grabs and suction sampler. Video and photo surveys were done using the SHRIMP towed vehicle and ROV Isis. Additional surveying and sampling was done at 1050?822 m depth across the summit of a seamount located at 48°44?N, 28°10?W on the western crest of the MAR between the two southern stations. JF - Marine Biology Research VL - 9 KW - Atlantic Ocean KW - mid-ocean ridge KW - benthos KW - trawling KW - coring KW - remotely operated vehicle SN - 1745-1000 TI - The ECO-MAR (Ecosystem of the Mid-Atlantic Ridge at the Sub-Polar Front and Charlie Gibbs Fracture Zone) project: description of the benthic sampling programme 2007?2010 SP - 624 AV - none EP - 628 ER - TY - JOUR ID - soton360965 UR - https://eprints.soton.ac.uk/360965/ A1 - Priede, Imants G. A1 - Billett, David S.M. A1 - Brierley, Andrew S. A1 - Hoelzel, A. Rus A1 - Inall, Mark A1 - Miller, Peter I. A1 - Cousins, Nicola J. A1 - Shields, Mark A. A1 - Fujii, Toyonobu Y1 - 2013/12/15/ N2 - The ECOMAR project investigated photosynthetically-supported life on the North Mid-Atlantic Ridge (MAR) between the Azores and Iceland focussing on the Charlie?Gibbs Fracture Zone area in the vicinity of the sub-polar front where the North Atlantic Current crosses the MAR. Repeat visits were made to four stations at 2500 m depth on the flanks of the MAR in the years 2007?2010; a pair of northern stations at 54°N in cold water north of the sub-polar front and southern stations at 49°N in warmer water influenced by eddies from the North Atlantic Current. At each station an instrumented mooring was deployed with current meters and sediment traps (100 and 1000 m above the sea floor) to sample downward flux of particulate matter. The patterns of water flow, fronts, primary production and export flux in the region were studied by a combination of remote sensing and in situ measurements. Sonar, tow nets and profilers sampled pelagic fauna over the MAR. Swath bathymetry surveys across the ridge revealed sediment-covered flat terraces parallel to the axis of the MAR with intervening steep rocky slopes. Otter trawls, megacores, baited traps and a suite of tools carried by the R.O.V. Isis including push cores, grabs and a suction device collected benthic fauna. Video and photo surveys were also conducted using the SHRIMP towed vehicle and the R.O.V. Isis. Additional surveying and sampling by landers and R.O.V. focussed on the summit of a seamount (48°44?N, 28°10?W) on the western crest of the MAR between the two southern stations. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 98 KW - Mid-ocean ridge KW - Marine protected area KW - North Atlantic KW - Benthic KW - Pelagic KW - Trawling KW - Bathymetry KW - Remotely operated vehicle KW - Charlie?Gibbs SN - 0967-0645 TI - The ecosystem of the Mid-Atlantic Ridge at the sub-polar front and Charlie?Gibbs Fracture Zone; ECO-MAR project strategy and description of the sampling programme 2007?2010 SP - 220 AV - none EP - 230 ER - TY - JOUR ID - soton301274 UR - https://eprints.soton.ac.uk/301274/ IS - 1 A1 - Priede, Imants G. A1 - Godbold, Jasmin A. A1 - King, Nicola A1 - Collins, Martin A. A1 - Bailey, David M. A1 - Gordon, John D.M. N2 - The ichthyofauna of ocean margin regions is characterised by a succession of different species occurring at different depths. This study was aimed at determining whether the resultant pattern of species richness with depth is a consequence of local factors in a given region or whether it simply reflects the global pattern of fish species distribution in the oceans. Along the ocean margin of the temperate NE Atlantic Ocean in the Porcupine Seabight and Abyssal Plain region, 48 degrees-53 degrees N, a total of 108 demersal fish species were identified from 187 trawls at depths from 240 to 4865 m. Fitting of species accumulation curves predicted an asymptote of 120, indicating that the fauna is 90% described. Baited cameras detected 22 scavenging species with a predicted asymptote of 24 species. Scavenging species represented a constant 22.7% (SD 3.5%) of the total species richness throughout the depth range studied. Species richness per trawl varied between a maximum of 16 at 1600 m and 4 on the abyssal plain > 4000 m with no significant influence of sea floor slope (a measure of topographic heterogeneity). Total species richness was 48 at 1600 m and 10 on the abyssal plain. There is a clear transition between slope species above 3000 m and abyssal species below. The depth at which peak species richness occurs (1100-2000 m) coincides with the depth of the permanent thermocline, presence of Mediterranean overflow water (MOW), seasonally strong currents, resuspension of particulate matter, high biomass of benthic filter feeders and pelagic biomass impinging on the slope. We suggest that these factors increase habitat and resource heterogeneity, thus supporting a wider range of fish species. The local pattern of species richness was compared with the global distribution of maximum depths of marine fish species from FishBase. Globally all three Classes of fishes, Agnatha, Chondrichthyes and Osteichthyes, showed a logarithmic decrease in species with depth, with the deepest observed species in each class occurring at 3003 m, 4156 m and 8370 m, respectively. In contrast, the local distribution of species maximum depths is idiosyncratic with a mean of 16.6 species maxima per 500 m at 1000-3000 m depth followed by three species per 500 m at 3500-4000 m and 11 species per 500 m at 5000 m. It is concluded that global patterns of species richness, as a source of recruitment, exert a weak influence on local patterns of species richness. Rather, global species richness is the sum of numerous regional and local patterns, each determined by characteristic environmental conditions. VL - 31 TI - Deep-sea demersal fish species richness in the Porcupine Seabight, NE Atlantic Ocean: global and regional patterns AV - restricted EP - 260 N1 - Funded by NERC: ECOMAR; Ecosystem of the Mid-Atlantic Ridge at the Sub-Polar Front and Charlie Gibbs Fracture Zone. (NE/C512961/1) Y1 - 2010/// JF - Marine Ecology KW - Atlantic Ocean KW - biodiversity KW - deep-sea KW - fish KW - ocean margins SN - 0173-9565 SP - 247 ER - TY - JOUR ID - soton374338 UR - https://eprints.soton.ac.uk/374338/ IS - 2 A1 - Prieto, E. A1 - González-Pola, C. A1 - Lavín, A. A1 - Holliday, N.P. Y1 - 2015/02// N2 - The oceanic hydrography of the north-easternmost region of the North Atlantic subtropical gyre has been monitored since 2003 by three sections extending between 100 and 200 nautical miles from the Spanish NW and N coast into the Atlantic and the Bay of Biscay. The sections were occupied twice a year from 2003 to 2010, annually after that, and measure the whole water column (>5000 m). Correlation of series in the vertical and among sections, autocorrelation and estimates of the effect of the noise induced by the mesoscale field, all indicate that observed signatures are robust changes of water masses at the regional scale. The hydrographic time series are not characterized by smooth trends but instead by shifts that persist through consecutive cruises. The most notable features include a shift to more saline central waters around 2005 after which they remained stable, and a decrease in thermohaline properties of the Labrador Sea Water from autumn 2008 to 2010. Years with a strong winter North Atlantic Oscillation (NAO) index are characterized by shifts in thermohaline properties across most of the intermediate levels, with the most notable event being the warming and increasing salinity that followed the large NAO index drop of 2010. The observations are consistent with current understanding of the large-scale functioning of the North Atlantic, which predicts a northeastward expansion of subtropical temperate waters in the eastern boundary as a response to NAO forcing. The observed variability is discussed in relationship to large-scale circulation. JF - Journal of Geophysical Research: Oceans VL - 120 KW - interannual variability KW - deep ocean KW - Northwest Iberia KW - NAO shifts KW - North Atlantic circulation SN - 2169-9275 TI - Interannual variability of the northwestern Iberia deep ocean: Response to large-scale North Atlantic forcing SP - 832 AV - public EP - 847 ER - TY - JOUR ID - soton383744 UR - https://eprints.soton.ac.uk/383744/ IS - 11 A1 - Pérez-Hernández, M.D. A1 - McCarthy, G.D. A1 - Vélez-Belchí, P. A1 - Smeed, D.A. A1 - Fraile-Nuez, E. A1 - Hernández-Guerra, A. Y1 - 2015/11/15/ N2 - This study examines the seasonal cycle of the Atlantic Meridional Overturning Circulation (AMOC) and its eastern boundary contributions. The cycle has a magnitude of 6 Sv, as measured by the RAPID/MOCHA/WBTS project array at 26°N, which is driven largely by the eastern boundary. The eastern boundary variations are explored in the context of the regional circulation around the Canary Islands. There is a 3 month lag between maximum wind forcing and the largest eastern boundary transports, which is explained in terms of a model for Rossby wave generated at the eastern boundary. Two dynamic processes take place through the Lanzarote Passage (LP) in fall: the recirculation of the Canary Current and the northward flow of the Intermediate Poleward Undercurrent. In contrast, during the remaining seasons the transport through the LP is southward due to the Canary Upwelling Current. These processes are linked to the seasonal cycle of the AMOC. JF - Journal of Geophysical Research: Oceans VL - 120 KW - AMOC KW - Canary Basin KW - eastern boundary KW - North Atlantic Subtropical Gyre KW - RAPID KW - EBC SN - 2169-9275 TI - The Canary Basin contribution to the seasonal cycle of the Atlantic Meridional Overturning Circulation at 26°N SP - 7237 AV - public EP - 7252 ER - TY - JOUR ID - soton44056 UR - http://www.agu.org/journals/jd/jd0710/2006JD007810/ IS - D10 A1 - Quartly, G.D. A1 - Kyte, E.A. A1 - Srokosz, M.A. A1 - Tsimplis, M.N. Y1 - 2007/// N2 - Large-scale patterns of precipitation are important for the changes they may effect upon the circulation of the ocean. However, marine precipitation is very hard to quantify accurately. Four independent climatologies are examined to compare their estimates of the annual mean precipitation, and the seasonal and interannual variations. One data set, Global Precipitation Climatology Project (GPCP), is based upon satellite data, the other three on output of weather forecast reanalyses from the National Centers for Environmental Prediction (NCEP) and the European Centre for Medium-range Weather Forecasts (ECMWF). Although all datasets have their errors, there is general agreement on the geographical patterns of precipitation. All the models had higher rain rates in the tropics than shown by the satellite data, and also greater seasonal ranges. However, GPCP has 10-25% more precipitation than NCEP and ECMWF in most of the southern regions, because of their weak representation of convergence zones; NCEP2, a more recent version of the NCEP reanalysis, shows a marked improvement in this area. However, in most regions NCEP2 exhibits a larger seasonal range than shown by other datasets, particularly for the tropical Pacific. Both NCEP and NCEP2 often show a seasonal cycle lagging two months or more behind GPCP. Of the three reanalysis climatologies, ECMWF appears best at realising the position and migration of rain features. The interannual variations are correlated between all four datasets, however the correlation coefficient is only large for regions that have a strong response to El Niño and La Niña event, or for comparisons of the two NCEP reanalyses. Of the datasets evaluated, GPCP has the most internal consistency, with no long-term trend in its regional averages, and it alone shows the deficit in Mediterranean precipitation coincident with the Eastern Mediterranean Transient. JF - Journal of Geophysical Research VL - 112 KW - Precipitation KW - Rainfall KW - Seasonal variation KW - Reanalysis fields KW - GPCP KW - NCEP KW - ECMWF KW - Atlantic KW - Indian KW - Pacific SN - 0148-0227 TI - An intercomparison of global oceanic precipitation climatologies AV - public ER - TY - JOUR ID - soton7877 UR - https://eprints.soton.ac.uk/7877/ IS - 1-4 A1 - Rabouille, C. A1 - Lampitt, R.S. Y1 - 2001/// N2 - Fluxes contributing to the particulate carbonate system in deep-sea sediments were investigated at the BENGAL site in the Porcupine Abyssal Plain (Northeast Atlantic). Deposition fluxes were estimated using sediment traps at a nominal depth of 3000 m and amounted to 0.37±0.1 mmol C m?2 d?1. Dissolution of carbonate was determined using flux of total alkalinity from in situ benthic chambers, is 0.4±0.1 mmol C m?2 d?1. Burial of carbonate was calculated from data on the carbonate content of the sediment and sedimentation rates from a model age based on 14C dating on foraminifera (0.66±0.1 mmol C m?2 d?1). Burial plus dissolution was three times larger than particle deposition flux which indicates that steady-state is not achieved in these sediments. Mass balances for other components (BSi, 210Pb), and calculations of the focusing factor using 230Th, show that lateral inputs play only a minor role in this imbalance. Decadal variations of annual particle fluxes are also within the uncertainty of our average. Long-term change in dissolution may contribute to the imbalance, but can not be the main reason because burial alone is greater than the input flux. The observed imbalance is thus the consequence of a large change of carbonate input flux which has occured in the recent past. A box model is used to check the response time of the solid carbonate system in these sediments and the time to reach a new steady-state is in the order of 3 kyr. Thus it is likely that the system has been perturbed recently and that large dissolution and burial rates reflect the previously larger particulate carbonate deposition rates. We estimate that particulate carbonate fluxes have certainly decreased by a factor of at least 3 and that this change has occurred during the last few centuries. JF - Progress in Oceanography VL - 50 KW - NORTH ATLANTIC OCEAN KW - CARBONATE KW - SEDIMENTS KW - CO2 KW - SAMPLING SN - 0079-6611 TI - Imbalance in the carbonate budget of surficial sediments in the North Atlantic Ocean: variations over the last millennium? SP - 201 AV - none EP - 221 ER - TY - JOUR ID - soton7856 UR - https://eprints.soton.ac.uk/7856/ IS - 1-4 A1 - Ragueneau, O. A1 - Gallinari, M. A1 - Corrin, L. A1 - Grandel, S. A1 - Hall, P. A1 - Hauvespre, A. A1 - Lampitt, R.S. A1 - Rickert, D. A1 - Stahl, H. A1 - Tengberg, A. A1 - Witbaard, R. Y1 - 2001/// N2 - Within the framework of the EU-funded BENGAL programme, the effects of seasonality on biogenic silica early diagenesis have been studied at the Porcupine Abyssal Plain (PAP), an abyssal locality located in the northeast Atlantic Ocean. Nine cruises were carried out between August 1996 and August 1998. Silicic acid (DSi) increased downward from 46.2 to 213 ?M (mean of 27 profiles). Biogenic silica (BSi) decreased from ca. 2% near the sediment?water interface to <1% at depth. Benthic silicic acid fluxes as measured from benthic chambers were close to those estimated from non-linear DSi porewater gradients. Some 90% of the dissolution occurred within the top 5.5 cm of the sediment column, rather than at the sediment?water interface and the annual DSi efflux was close to 0.057 mol Si m?2 yr?1. Biogenic silica accumulation was close to 0.008 mol Si m?2 yr?1 and the annual opal delivery reconstructed from sedimentary fluxes, assuming steady state, was 0.065 mol Si m?2 yr?1. This is in good agreement with the mean annual opal flux determined from sediment trap samples, averaged over the last decade (0.062 mol Si m?2 yr?1). Thus ca. 12% of the opal flux delivered to the seafloor get preserved in the sediments. A simple comparison between the sedimentation rate and the dissolution rate in the uppermost 5.5 cm of the sediment column suggests that there should be no accumulation of opal in PAP sediments. However, by combining the BENGAL high sampling frequency with our experimental results on BSi dissolution, we conclude that non-steady state processes associated with the seasonal deposition of fresh biogenic particles may well play a fundamental role in the preservation of BSi in these sediments. This comes about though the way seasonal variability affects the quality of the biogenic matter reaching the seafloor. Hence it influences the intrinsic dissolution properties of the opal at the seafloor and also the part played by non-local mixing events by ensuring the rapid transport of BSi particles deep into the sediment to where saturation is reached. JF - Progress in Oceanography VL - 50 KW - northeast atlantic ocean KW - biogenic silica KW - biogenic opal KW - sediments SN - 0079-6611 TI - The benthic silica cycle in the northeast Atlantic: annual mass balance, seasonality, and importance of non-steady-state processes for the early diagenesis of biogenic opal in deep-sea sediments SP - 171 AV - none EP - 200 ER - TY - JOUR ID - soton8912 UR - https://eprints.soton.ac.uk/8912/ IS - 3 A1 - Ramirez Llodra, E. A1 - Tyler, P.A. A1 - Copley, J.T.P. Y1 - 2000/// JF - Journal of the Marine Biological Association of the United Kingdom VL - 80 KW - SHRIMPS KW - REPRODUCTION KW - HYDROTHERMAL COMMUNITIES KW - MID ATLANTIC RIDGE KW - TAG KW - RAINBOW KW - SNAKE PIT KW - LUCKY STRIKE SN - 0025-3154 TI - Reproductive biology of three caridean shrimp, Rimicaris exoculata, Chorocaris chacei and Mirocaris fortunata (Caridea: Decapoda), from hydrothermal vents SP - 473 AV - none EP - 484 ER - TY - RPRT ID - soton347671 UR - https://eprints.soton.ac.uk/347671/ A1 - Rayner, D. A1 - Baringer, M. A1 - et al, Y1 - 2012/12// N2 - This report describes the UK mooring operations conducted during RV Ronald H. Brown cruise RB1201 between 15 February and 5 March 2012. These mooring operations were completed as part of the United Kingdom Natural Environment Research Council (NERC) funded RAPID-WATCH Programme to monitor the Atlantic Meridional Overturning Circulation (MOC) at 26.5°N.
This cruise was a joint cruise between staff from the NERC and staff from the US National Oceanic and Atmospheric Administration (NOAA)?s Atlantic Oceanographic and Meterological Laboratory (AOML) in Miami. The primary purpose on this cruise for the UK team was to service the RAPID Western Boundary moorings while the US team worked on the NOAA Western Boundary Time Series project.
Cruise RB1201 was from Charleston, South Carolina, USA to Charleston, South Carolina, USA and covered the Western Boundary moorings deployed on cruise KN200-4 in 2011 and landers deployed on cruise OC459 in 2010. This cruise was the ninth refurbishment (following initial deployment in 2004) of the Western Boundary section of an array of moorings deployed across the Atlantic in order to continuously observe the MOC. This array will be further refined and refurbished during subsequent years.
The instruments deployed on the array consist of a variety of current meters, bottom pressure recorders, and CTD loggers, which, combined with time series measurements of the Florida Straits Current and wind stress estimates, will be used to determine the strength and structure of the MOC at 26.5°N.
(http://www.noc.soton.ac.uk/rapid) PB - National Oceanography Centre T3 - 19 KW - 26.5°N KW - Atlantic Ocean KW - bottom pressure recorder KW - BPR KW - CTD KW - current meter KW - Meridional overturning circulation KW - MicroCAT KW - MOC KW - mooring array KW - Moorings KW - North Atlantic KW - RAPID-WATCH KW - RAPID KW - RAPIDMOC KW - RB1201 KW - Ronald H. Brown KW - THC KW - thermohaline circulation KW - Western Boundary M1 - project_report TI - RV Ronald H. Brown Cruise RB1201, 15 Feb - 05 Mar 2012. RAPID moorings cruise report AV - public EP - 90 ER - TY - RPRT ID - soton15333 UR - https://eprints.soton.ac.uk/15333/ A1 - Rayner, D. A1 - Cunningham, S.A. Y1 - 2005/// N2 - This report describes the mooring operations conducted during RRS Discovery Cruises D277 and D278. These cruises were conducted between 26 February 2004 and 30 March 2004, as part of the Natural Environment Research Council (NERC) funded RAPID Programme to monitor the Atlantic Meridional Overturning Circulation at 26.5N.

Cruise D277 was from Tenerife to the Bahamas with participants from the Southampton Oceanography Centre (SOC), with cruise D278 a barter cruise also involving participants from the Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami.

An array of moorings were deployed across the Atlantic in order to set up a pre-operational prototype system to continuously observe the Atlantic Meridional Overturning Circulation (MOC). This array will be refined and refurbished during subsequent years.

The deployed mooring array consisted of 19 moorings from the SOC, with 3 from the RSMAS. Moorings are focused at the Eastern and Western boundaries, along with a grouping at the Mid Atlantic Ridge.

The instruments deployed on the array consists of a variety of current meters, bottom pressure recorders and CTD loggers which, combined with time series measurements of the Florida Channel Current and wind stress estimates, will be used to determine the strength and structure of the MOC at 26.5N. PB - Southampton Oceanography Centre, University of Southampton T3 - 53 KW - Atlantic Ocean KW - bottom pressure recorder KW - BPR KW - cruise D277 2004 KW - cruise D278 2004 KW - CTD KW - current meter KW - Discovery KW - Meridional Overturning Circulation KW - MOC KW - mooring array KW - Moorings KW - North Atlantic KW - RAPID KW - RAPIDMOC KW - THC KW - thermohaline circulation M1 - project_report TI - RRS Discovery Cruises 277/278, RAPID mooring cruise report, February - March 2004 AV - public EP - 103 ER - TY - RPRT ID - soton72126 UR - https://eprints.soton.ac.uk/72126/ A1 - Rayner, D. Y1 - 2009/12// N2 - This report describes the mooring operations conducted during RV Ronald H. Brown cruise
RB0901 between 15 April and 5 May 2009.
These mooring operations were completed as part of the United Kingdom Natural Environment
Research Council (NERC) funded RAPID-WATCH Programme to monitor the Atlantic
Meridional Overturning Circulation at 26.5°N. The primary purpose on this cruise for the UK
team was to service the RAPID Western Boundary moorings while the US team worked on the
Western Boundary Time Series project.
Cruise RB0901 was from Charleston, South Carolina to Charleston, South Carolina and
covered the Western Boundary moorings deployed on cruises SJ08 and RB0701. This cruise
was the seventh annual refurbishment of the Western Boundary section of an array of moorings
deployed across the Atlantic in order to continuously observe the Atlantic Meridional
Overturning Circulation (MOC). This array will be further refined and refurbished during
subsequent years.
The instruments deployed on the array consist of a variety of current meters, bottom pressure
recorders, and CTD loggers, which, combined with time series measurements of the Florida
Channel Current and wind stress estimates, will be used to determine the strength and structure
of the MOC at 26.5°N.
(http://www.noc.soton.ac.uk/rapid) PB - National Oceanography Centre T3 - 40 KW - 26.5°N KW - Atlantic Ocean KW - bottom pressure recorder KW - BPR KW - cruise RB0901 2009 KW - CTD KW - current meter KW - meridional overturning circulation KW - MicroCAT KW - MOC KW - mooring array KW - moorings KW - North Atlantic KW - RAPID KW - RAPIDMOC KW - RAPID-WATCH KW - Ronald H. Brown KW - THC KW - thermohaline circulation KW - Western Boundary ED - Wright, P.G. M1 - project_report TI - RV Ronald H. Brown Cruise RB0901, 15 Apr-06 May 2009. RAPID Mooring Cruise Report AV - public EP - 121 ER - TY - JOUR ID - soton174949 UR - https://eprints.soton.ac.uk/174949/ IS - 17-18 A1 - Rayner, Darren A1 - Hirschi, Joël J.-M. A1 - Kanzow, Torsten A1 - Johns, William E. A1 - Wright, Paul G. A1 - Frajka-Williams, Eleanor A1 - Bryden, Harry L. A1 - Meinen, Christopher S. A1 - Baringer, Molly O. A1 - Marotzke, Jochem A1 - Beal, Lisa M. A1 - Cunningham, Stuart A. Y1 - 2011/09// N2 - The rapid climate change programme (RAPID) has established a prototype system to continuously observe the strength and structure of the Atlantic meridional overturning circulation (MOC) at 26.5°N. Here we provide a detailed description of the RAPID-MOC monitoring array and how it has evolved during the first four deployment years, as well as an overview of the main findings so far. The RAPID-MOC monitoring array measures: (1) Gulf Stream transport through Florida Strait by cable and repeat direct velocity measurements; (2) Ekman transports by satellite scatterometer measurements; (3) Deep Western Boundary Currents by direct velocity measurements; (4) the basin wide interior baroclinic circulation from moorings measuring vertical profiles of density at the boundaries and on either side of the Mid-Atlantic Ridge; and (5) barotropic fluctuations using bottom pressure recorders. The array became operational in late March 2004 and is expected to continue until at least 2014. The first 4 years of observations (April 2004?April 2008) have provided an unprecedented insight into the MOC structure and variability. We show that the zonally integrated meridional flow tends to conserve mass, with the fluctuations of the different transport components largely compensating at periods longer than 10 days. We take this as experimental confirmation of the monitoring strategy, which was initially tested in numerical models. The MOC at 26.5°N is characterised by a large variability?even on timescales as short as weeks to months. The mean maximum MOC transport for the first 4 years of observations is 18.7 Sv with a standard deviation of 4.8 Sv. The mechanisms causing the MOC variability are not yet fully understood. Part of the observed MOC variability consists of a seasonal cycle, which can be linked to the seasonal variability of the wind stress curl close to the African coast. Close to the western boundary, fluctuations in the Gulf Stream and in the North Atlantic Deep Water (NADW) coincide with bottom pressure variations at the western margin, thus suggesting a barotropic compensation. Ongoing and future research will put these local transport variations into a wider spatial and climatic context. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 58 KW - Physical oceanography KW - Thermohaline circulation KW - Ocean circulation KW - Ocean currents KW - Mooring systems KW - Atlantic meridional overturning circulation SN - 0967-0645 TI - Monitoring the Atlantic Meridional Overturning Circulation SP - 1744 AV - none EP - 1753 ER - TY - RPRT ID - soton163913 UR - https://eprints.soton.ac.uk/163913/ A1 - Read, J.F. Y1 - 2010/// N2 - The Extended Ellett Line is a full-depth hydrographic section between Iceland, 60°N 20°W, Rockall and Scotland. The original Ellett Line across the Rockall Trough was first occupied in 1975 when measurements were attempted four times a year. In 1996 the line was extended to Iceland and occupied approximately annually. The data form a 35 year time-series of the oceanic conditions west of the British Isles.

The section monitors the characteristics of the warm water inflow into the Nordic Seas and thence to the Arctic, and observes part of the returning cold water outflow with measurements of the Iceland-Scotland Overflow and the overflow of the Wyville-Thomson Ridge into the Rockall Trough.

The 2010 occupation, RRS Discovery Cruise 351, was completed successfully with 48 CTD stations worked between the Iceland and Scotland shelf edges. Additionally, Line G, part of the SAMS observation network of the Scottish continental shelf was completed. Samples were taken for inorganic nutrients, iron and trace metals, bioluminescence and microscope analysis. Incubation experiments were performed to investigate the role of microzooplankton grazing and the speciation of iron, and to investigate the presence of dinoflagellate bioluminescence.

In addition to the planned programme, sampling took place to investigate the extent of the fall out from the ash plume emitted by the Iceland volcano, Ejyafjallajokull, and its impact on the biogeochemistry and productivity of the upper ocean.

A trial tow of SeaSoar and a short survey of the upper ocean over the Anton Dohrn seamount were successfully completed. PB - National Oceanography Centre T3 - 50 KW - cruise 351 2010 KW - CTD observations KW - Discovery KW - Ellett Line KW - Iceland Basin KW - North Atlantic KW - Rockall Trough KW - SeaSoar observations M1 - project_report TI - RRS Discovery Cruise 351, 10-28 May 2010. The Extended Ellett Line 2010. AV - public EP - 117 ER - TY - RPRT ID - soton17390 UR - https://eprints.soton.ac.uk/17390/ A1 - Read, J.F. Y1 - 2005/// N2 - This report describes R/V Poseidon Cruise 314, designed to repeat the hydrographic section from Scotland to Rockall, called the Ellett Line, and its extension to Iceland.

73 stations were worked with CTD and lowered ADCP and sampled for chemical (macronutrients and dissolved oxygen) and biological (chlorophyll a) analyses. Additional samples for analysis of dissolved iron, pigments and plankton physiology were taken at a few selected sites. Underway measurements of depth, meteorology, surface water properties and currents were made. The weather during the cruise was good, with no time lost to the elements and more than the expected number of stations worked. Conversely data logging and processing suffered from so many problems that it was not possible to edit and calibrate the data during the cruise. PB - Southampton Oceanography Centre, University of Southampton T3 - 58 KW - ADCP KW - ATLN KW - chlorophyll KW - Cruise 314 2004 KW - CTD observations KW - FRRF KW - Iceland Basin KW - dissolved iron KW - LADCP KW - North Atlantic KW - nutrients KW - oxygen KW - Poseidon KW - repeat hydrography KW - Rockall Trough KW - salinity KW - VM-ADCP M1 - project_report TI - RV "Poseidon" Cruise 314, 11 Jul - 23 Jul 2004. The 'Extended Ellett Line?, Scotland - Rockall - Iceland time series AV - public EP - 68 ER - TY - RPRT N1 - New series incorporating reports from NOC Liverpool and Southampton Sites ID - soton200115 UR - https://eprints.soton.ac.uk/200115/ A1 - Read, J.F. A1 - et al, Y1 - 2011/10// N2 - The Extended Ellett Line is a full-depth hydrographic section between Iceland, 60°N 20°W, Rockall and Scotland. The original Ellett Line across the Rockall Trough was first occupied in 1975 when measurements were attempted four times a year. In 1996 the line was extended to Iceland and since then has been occupied approximately annually. The data form a 35 year time series of the oceanic conditions west of the British Isles.

The section monitors the characteristics of the warm water inflow into the Nordic Seas and thence to the Arctic, and observes part of the returning cold water outflow with easurements of the Iceland-Scotland Overflow and the overflow of the Wyville-Thomson Ridge into the Rockall Trough.

The 2011 occupation, RRS Discovery cruise 365, was curtailed by both technical problems and bad weather. 45 of the 48 CTD stations were worked between the Iceland and Scotland shelf edges. Line G, part of the SAMS observation network of the Scottish continental shelf was partially completed, with 4 stations at the western end not worked. Samples were taken for CFC and SF6 analysis, DIC and alkalinity, inorganic nutrients, aluminium, POC, bacterial abundance and biomass, and for phytoplankton community structure. Plans to repeat stations, to collect validation data for the SAMS glider and to investigate eddies in the Rockall Trough had to be abandoned. PB - National Oceanography Centre T3 - 6 KW - cruise 365 2011 KW - CTD observations KW - Discovery KW - Ellett Line KW - Iceland Basin KW - North Atlantic KW - Rockall Trough M1 - project_report TI - RRS Discovery Cruise 365, 11 May-02 Jun 2011. The Extended Ellett Line 2011 AV - public EP - 90 ER - TY - JOUR ID - soton63462 UR - http://www.int-res.com/abstracts/meps/v374/p7-12/ A1 - Rees, Andrew P. A1 - Gilbert, Jack A. A1 - Kelly-Gerreyn, Boris A. Y1 - 2009/// N2 - In temperate Atlantic waters (18.8 to 20.1°C), biological nitrogen fixation has been
demonstrated by 2 independent measurements: 15N-N2 incorporation and nifH identification in the
DNA and expressed messenger RNA (mRNA). At 2 stations in the western English Channel, bulk
waters were incubated with 15N-N2. At the high levels of particulate nitrogen (?11.5 ?mol N l?1),
absolute fixation rates of 18.9 ± 0.01 and 20.0 nmol N l?1d?1 were determined. While a caveat must
accompany the magnitude of the rates presented due to the limited number of data, the presence and
activity of diazotrophic organisms in these waters is of ecological significance and may affect current
attitudes to nitrogen and carbon budgets. In particular, our estimate of the rate of N fixation
(0.35 mmol N m?2 d?1) is comparable to that of denitrification rates in UK shelf seas. Molecular analysis
identified a diversity of expressed nifH genes, and 21 different prokaryotic nifH transcripts were
identified. JF - Marine Ecology Progress Series VL - 374 KW - Temperate Atlantic · Nitrogen fixation · Diazotrophy · nifH · Western English Channel SN - 0171-8630 TI - Nitrogen fixation in the western English Channel (NE Atlantic Ocean) SP - 7 AV - public EP - 12 ER - TY - JOUR ID - soton50276 UR - http://www.agu.org/journals/gb/gb0704/2006GB002886/ A1 - Reynolds, S.E. A1 - Mather, R.L. A1 - Wolff, G.A. A1 - Williams, R.G. A1 - Landolfi, A. A1 - Sanders, R. A1 - Woodward, E.M.S. Y1 - 2007/// N2 - The spatial extent of N2 fixation in the Atlantic Ocean is examined by determining the isotopic composition of N in suspended particulate organic nitrogen (?15N PONsusp). The samples were collected from zonal and meridional transects of the Atlantic Ocean during a 3-year period. There is a consistent depleted ?15N PONsusp signal extending over the center of the northern subtropical gyre, which partly coincides with a region where the tracer N* increases westward following the gyre circulation. This nonconservative behavior of N* implies that N2 fixation is responsible for the depleted ?15N PONsusp. A mixing model suggests that N2 fixation over parts of the northern gyre provides up to 74% of the N utilized by phytoplankton. However, since the PONsusp represents only a small fraction of the total N pool, N2 fixation probably only plays a minor role in supplying new N to the euphotic zone in the surface waters of the northern subtropical gyre. JF - Global Biogeochemical Cycles VL - 21 KW - nitrogen fixation KW - North Atlantic KW - Atlantic meridional transect SN - 0886-6236 TI - How widespread and important is N2 fixation in the North Atlantic Ocean? AV - none ER - TY - RPRT ID - soton304 UR - https://eprints.soton.ac.uk/304/ A1 - Rice, A.L. Y1 - 1998/// N2 - Discovery Cruise 231 was the fifth of a series of cruises within a 3-year contract (MAS3 CT950018), BENGAL, funded under the MAST III programme of the EU and running from February 1996 to January 1999. The overall objective of the contract is to monitor the influence of the seasonal sedimentation of phytodetritus on the benthic biology and chemistry of a study site on the Porcupine Abyssal Plain.

Like the second BENGAL cruise (Discovery 226, March/April 1997) cruise 231 was timed to precede the current year?s input of phytodetritus expected in May/June. The intention was to obtain a series of samples and data to compare with those taken during cruise 226 and to service deployed moorings. The cruise generally experienced good weather and, with the exception of some gear failures, was very successful, achieving almost all of the intended sampling. PB - Southampton Oceanography Centre, University of Southampton T3 - 18 KW - BENGAL KW - benthic communities KW - bioturbation KW - bottom photography KW - coring KW - cruise 231 1998 KW - current meters KW - detritus KW - Discovery KW - landers KW - microbiology KW - Northeast Atlantic KW - respirometry KW - sediment geochemistry KW - sediment traps KW - trawling KW - water sampling M1 - project_report TI - RRS Discovery Cruise 231, 28 Feb-30 Mar 1998. BENGAL: High resolution temporal and spatial study of the BENthic biology and Geochemistry of a north-eastern Atlantic abyssal Locality AV - public EP - 84 ER - TY - RPRT ID - soton308 UR - https://eprints.soton.ac.uk/308/ A1 - Rice, A.L. Y1 - 1997/// N2 - Discovery Cruise 226 (Leg 2) was the second of a series of cruises within a 3-year contract (MAS3 CT950018), BENGAL, funded under the MAST III programme of the EU and running from February 1996 to January 1999. The overall objective of the contract is to monitor the influence of the seasonal sedimentation of phytodetritus on the benthic biology and chemistry of a study site on the Porcupine Abyssal Plain.

Cruise 226 was timed to precede the current year?s input of phytodetritus expected in May/June. The intention was to obtain a series of samples and data as long as possible after the previous year?s input and to service deployed moorings. The cruise experienced excellent weather and, with the exception of some gear failures and losses, the most serious being the loss of an imprint lander system, was very successful, achieving almost all of the intended sampling. PB - Southampton Oceanography Centre, University of Southampton T3 - 13 KW - benthic communities KW - bioturbation KW - coring KW - cruise 226 1997 KW - current meters KW - detritus KW - Discovery KW - landers KW - microbiology KW - Northeast Atlantic KW - photography KW - respirometry KW - sediment chemistry KW - sediment traps KW - trawling KW - water sampling M1 - project_report TI - RRS Discovery Cruise 226, 12 Mar-10 Apr 1997. BENGAL: High resolution temporal and spatial study of the BENthic biology and Geochemistry of a north-eastern Atlantic abyssal Locality AV - public EP - 76 ER - TY - RPRT ID - soton317 UR - https://eprints.soton.ac.uk/317/ A1 - Rice, A.L. Y1 - 1996/// N2 - Discovery Cruise 222 (Leg 2) was the first of a series of cruises within a 3-year contract (MAS3 CT950018), BENGAL, funded under the MAST III programme of the EU and running from February 1996. The contract will concentrate on a single north-eastern Atlantic abyssal locality centred on 48°50?N: 16°30?W and will study in detail changes in the benthic system over one 12-month period from March 1997 to March 1998, particularly in relation to the seasonal deposition of phytodetritus.

This cruise was a lead-in to this series, with the objective of obtaining baseline data from benthic and mid-water sampling gears and from both short and long-term deployed moorings/landers. It was also an opportunity to test and refine new experimental procedures in preparation for the detailed studies in 1997-98. PB - Southampton Oceanography Centre, University of Southampton T3 - 4 KW - benthic communities KW - bioturbation KW - coring KW - cruise 222 1996 KW - current meters KW - detritus KW - Discovery KW - landers KW - microbiology KW - Northeast Atlantic KW - photography KW - respirometry KW - sediment chemistry KW - sediment traps KW - trawling KW - water sampling M1 - project_report TI - RRS Discovery Cruise 222, Leg 2, 29 Aug-24 Sep 1996. BENGAL: High resolution temporal and spatial study of the BENthic biology and Geochemistry of a north-eastern Atlantic abyssal Locality AV - public EP - 86 ER - TY - RPRT ID - soton42071 UR - https://eprints.soton.ac.uk/42071/ A1 - Rijkenberg, M. A1 - Achterberg, E. Y1 - 2006/// N2 - The "Poseidon" 332 cruise in the Cape Verde Island region was undertaken as part of the UK-SOLAS project (Surface-Ocean / Lower-Atmosphere Study, websites: www.solas-int.org and www.nerc.ac.uk/funding/thematics/solas/) to improve understanding of the atmospheric transport, cycling and deposition of dust and nutrients into the North Atlantic. The cruise was funded by NERC. The objectives of the cruise were:

1) Obtain an improved temporal and spatial estimate of atmospheric dust input to the Tropical N Atlantic.
2) Obtain an improved estimate of the seawater dissolution of N, P and Fe species from aerosol dust.
3) Determine the influence dust exerts on phytoplankton carbon fixation, species diversity and nutrient cycling in surface waters.
4) Determine the impact of atmospheric dust derived micronutrients on microbial community production and species diversity in the surface microlayer and underlying waters.

In particular this cruise aimed to combine in-situ aircraft measurements of the atmosphere (DODO, University of Reading, www.met.rdg.ac.uk/~aer/dodo/dodo.html) with in situ sampling of the lower atmosphere and the water column (University of East Anglia, University of Southampton, National Oceanography Centre Southampton and University of Birmingham) around the Cape Verde islands. However, the Poseidon did not meet up with the aircraft due to a lack of dust in the atmosphere.

The main sampling and data-gathering activities comprised 21 stations for CTD and GoFlo profiles, 175 underway samples from the towed Fish and 6 samples of the surface microlayer. Stand Alone Pumps (SAPS) were deployed 4 times but without success.

One dust event was encountered at 4-8 Feb. The transect sailed at 3-4 Feb. during the dust event was again sampled a week later to investigate changes in nutrients, trace-metals and the microbial community. The Cape Verde Time Series Station was sampled at 9 Feb. PB - Natural Environment Research Council KW - aerosol time-of-flight mass spectrometry KW - aerosols KW - amino acids KW - bacteria KW - canary current KW - cape verde islands KW - CTD observations KW - dissolved aluminum KW - dissolved iron KW - dust KW - equatorial north-atlantic KW - FRRF system KW - GoFlo casts KW - HEME KW - heterotrophic activity KW - high volume aerosol sampler KW - marine productivity KW - microlayer KW - nanomolar nutrients KW - nitrogen fixation KW - nutrients KW - organic iron complexation KW - phytoplankton KW - pigments KW - poseidon KW - primary production KW - sahara KW - salinity KW - satellite images KW - sea surface temperature KW - species diversity M1 - project_report TI - RV Poseidon cruise 332. Chasing Saharan Dust Storms: winter, 26 January - 26 February 2006 AV - public EP - 72 ER - TY - JOUR ID - soton41433 UR - https://eprints.soton.ac.uk/41433/ IS - 11 A1 - Rijkenberg, Micha J.A. A1 - Gerringa, Loes J.A. A1 - Carolus, Vicky E. A1 - Velzeboer, Ilona A1 - de Baar, Hein J.W. Y1 - 2006/06/01/ N2 - In laboratory experiments, we investigated the effect of five individual Fe-binding ligands: phaeophytin, ferrichrome, desferrioxamine B (DFOB), inositol hexaphosphate (phytic acid), and protoporphyrin IX (PPIX) on the Fe(II) photoproduction using seawater of the open Southern Ocean. Addition of 10-100 nM Fe(III) to open Southern Ocean seawater without the model ligands and containing; 1.1 nM dissolved Fe(III), 1.75 +/- 0.28 equivalents of nM Fe of natural ligands with a conditional stability constant (log K) of 21.75 +/- 0.34 and a concentration DOC of 86.8 +/- 1.13 M C leads to the formation of amorphous Fe(III) hydroxides. These amorphous Fe(III) hydroxides are the major source for the photoproduction of Fe(II). The addition of the model ligands changed the Fe(II) photoproduction considerably and in various ways. Phaeophytin showed higher Fe(II) photoproduction than ferrichrome and the control, i.e., amorphous Fe(III) hydroxides. Additions of phytic acid between 65 and 105 nM increased the concentration of photoproduced Fe(II) with 0.16 nM Fe(II) per nM phytic acid, presumably due to the co-aggregation of Fe(III) and phytic acid leading via an increasing colloidal surface to an increasing photoreducible Fe(III) fraction. DFOB and PPIX strongly decreased the photoproduced Fe(II) concentration. The low Fe(II) photoproduction with DFOB confirmed reported observations that Fe(III) complexed to DFOB is photo-stable. The PPIX hardly binds Fe(III) in the open Southern Ocean seawater but decreased the photoproduced Fe(II) concentration by complexing the Fe(II) with a binding rate constant of k(Fe(II)PPIX) = 1.04 x 10(-4) 1.53 x 10(-5) s(-1) nM(-1) PPIX. Subsequently, PPIX is suggested to act as a photo sensitizing producer of superoxide, thus increasing the dark reduction of Fe(III) to Fe(II). Our research shows that the photochemistry of Fe(III) and the resulting photoproduced Fe(II) concentration is strongly depending on the identity of the Fe-binding organic ligands and that a translation to natural conditions is not possible without further characterization of the natural occurring ligands. JF - Geochimica et Cosmochimica Acta VL - 70 KW - diatom thalassiosira-weissflogii KW - cathodic stripping voltammetry KW - thiol-containing compounds KW - equatorial pacific-ocean KW - natural organic-ligands KW - open southern-ocean KW - atlantic-ocean KW - dissolved iron KW - inositol hexaphosphate KW - siderophore production SN - 0016-7037 TI - Enhancement and inhibition of iron photoreduction by individual ligands in open ocean seawater SP - 2790 AV - none EP - 2805 ER - TY - JOUR ID - soton52016 UR - https://eprints.soton.ac.uk/52016/ IS - 1-2 A1 - Rijkenberg, Micha J.A. A1 - Powell, Claire F. A1 - Dall'Osto, Manuel A1 - Nielsdottir, Maria C. A1 - Patey, Matthew D. A1 - Hill, Polly G. A1 - Baker, Alex R. A1 - Jickells, Tim D. A1 - Harrison, Roy M. A1 - Achterberg, Eric P. N2 - Concentrations of dissolved iron (DFe) and Fe-binding ligands were determined in the tropical Northeast Atlantic Ocean (12?30°N, 21?29°W) as part of the UK-SOLAS (Surface Ocean Lower Atmosphere Study) cruise Poseidon 332 (P332) in January?February 2006. The surface water DFe concentrations varied between 0.1 and 0.4 nM with an average of 0.22 ± 0.05 nM (n = 159). The surface water concentrations of total Fe-binding ligands varied between 0.82 and 1.46 nM with an average of 1.11 ± 0.14 nM (n = 33). The concentration of uncomplexed Fe-binding ligands varied between 0.64 and 1.35 nM with an average of 0.90 ± 0.14 nM (n = 33). Thus, on average 81% of the total Fe-binding ligand concentration was uncomplexed. The average logarithmic conditional stability constant of the pool of Fe-binding ligands was 22.85 ± 0.38 with respect to Fe3+ (n = 33). A transect (12°N, 26°W to 16°N, 25.3°W) was sailed during a small Saharan dust event and repeated a week later. Following the dust event, the concentration of DFe increased from 0.20 ± 0.026 nM (n = 125) to 0.25 ± 0.028 (n = 17) and the concentration of free Fe-binding ligands decreased from 1.15 ± 0.15 (n = 4) to 0.89 ± 0.10 (n = 4) nM. Furthermore, the logarithmic stability constants of the Fe-binding ligands south of the Cape Verde islands were distinctively lower than north of the islands. The absence of a change in the logarithmic stability constant after the dust event south of the Cape Verde islands suggests that there was no significant atmospheric input of new Fe-binding ligands during this dust event. VL - 110 TI - Changes in iron speciation following a Saharan dust event in the tropical North Atlantic Ocean AV - none EP - 67 N1 - Actually deposited by Jane Conquer Y1 - 2008/05/16/ JF - Marine Chemistry KW - atmospheric input KW - aerosols KW - saharan dust KW - dry deposition KW - dissolved iron KW - organic iron complexation KW - equatorial atlantic ocean SN - 0304-4203 SP - 56 ER - TY - JOUR ID - soton54695 UR - http://www.agu.org/pubs/crossref/2008/2007PA001524.shtml A1 - Ripperger, S. A1 - Schiebel, R. A1 - Rehkamper, M. A1 - Halliday, A.N. Y1 - 2008/// N2 - The Cd/Ca ratios of planktonic foraminiferal tests have been used to reconstruct surface water nutrient utilization and paleoproductivity. The reliability of this proxy has hitherto not been comprehensively studied, however. To fill this gap, we present novel Cd/Ca data for in situ sampled and sedimentary planktonic foraminifers of the species Globigerinoides ruber, G. sacculifer, Globigerina bulloides, Orbulina universa, and Globorotalia truncatulinoides from the Arabian Sea and the North Atlantic. The Cd/Ca ratios obtained for G. ruber sampled from the live habitat generally display a correlation with seawater phosphate content, but no such trend is observed for G. sacculifer. This distinct behavior may reflect different ecological niches or species-specific incorporation of Cd into the calcite shells of the organisms. The Cd/Ca ratios of G. ruber, G. sacculifer, and G. bulloides from surface sediments are consistently higher than those obtained for live collected specimens of the same species. Postdepositional alteration of the tests is unlikely to be responsible for these systematic differences. Rather, they appear to reflect a combination of factors, including the formation of calcite crusts with high Cd contents, the different timescales that are represented by in situ and sedimentary foraminiferal tests, and the dominance of tests from periods of high productivity in sediments. Our results also reveal higher Cd/Ca ratios for live G. ruber than for settling tests of the same species. This suggests that planktonic foraminiferal shells are partially dissolved while they individually settle through the water column. Sedimentary tests, however, will be less affected by dissolution processes because these shells are primarily deposited in mass sinking events, which feature much higher settling velocities than those experienced by single settling shells.
JF - Paleoceanography VL - 23 KW - planktonic foraminifers KW - cadmium KW - paleoproductivity KW - Cd/Ca KW - Atlantic KW - Arabian Sea SN - 0883-8305 TI - Cd/Ca ratios of in situ collected planktonic foraminiferal tests AV - none ER - TY - JOUR ID - soton8800 UR - http://ams.allenpress.com/amsonline/?request=get-abstract&issn=1520-0485&volume=030&issue=01&page=0067 IS - 1 A1 - Robbins, P.E. A1 - Price, J.F. A1 - Owens, W.B. A1 - Jenkins, W.J. Y1 - 2000/// N2 - An analysis of the physical mechanisms contributing to the ventilation of the lower subtropical thermocline (26.5 < ?? < 27.3) of the North Atlantic is presented. Examination of the surface forcing suggests that this density range in the Atlantic should be strongly ventilated by flow from the surface winter mixed layer. In contrast to this expectation, the isopycnic distribution of tracers within the shielded thermocline fails to show evidence of net advective penetration of recently ventilated waters into the eastern North Atlantic. Instead, the presence of the Azores Current appears to block the net southward invasion of mass from the region of the isopycnal surface outcrops. Tracer properties of recently ventilated waters enter the gyre by diffusive exchange across the Azores Front. Evidence of this diffusive ventilation based on both steady-state and transient tracers is presented. Mean basin-scale property distributions on ?? = 27.0 are diagnosed from an expanded high quality hydrographic database. The Montgomery streamfunction revels no evidence of pathways for direct geostrophic ventilation on this density horizon; low values of potential vorticity are confined to the region of formation north of the Azores Current.
To complement the examination of the steady-state tracer distribution, an interpretation of the temporal evolution of the tritium?3He age in the eastern Atlantic is considered. The penetration of the coupled tritium and 3He tracers provide a sensitive diagnostic of the effects of mixing. Lateral mixing creates robust and predictable changes in measured Eulerian tritium?3He age in response to the oceanic input of anthropogenic tritium. Simple kinematic models of the ventilation of tritium and 3He are compared with the observed temporal character of the tracer age field. Circulation scenarios characterized by net export of fluid from the surface mixed layer into the lower subtropical thermocline require excessively large magnitudes of lateral diffusivity (?4000 m2 s-1) to accurately simulate the transient tracer observations. On the other hand, the observations can be reconciled with canonical magnitudes of lateral diffusion (1000?1500 m2 s-1) if the ventilation of properties is mediated by diffusive transmission across the Azores Current accompanied by only negligible net transport of mass.
JF - Journal of Physical Oceanography VL - 30 KW - WOCE KW - THERMOCLINE KW - VENTILATION KW - DIFFUSION KW - NORTH ATLANTIC OCEAN KW - TRACERS KW - OCEAN CIRCULATION SN - 0022-3670 TI - The importance of lateral diffusion for the ventilation of the lower thermocline in the sub-tropical North Atlantic SP - 67 AV - none EP - 89 ER - TY - JOUR ID - soton360004 UR - https://eprints.soton.ac.uk/360004/ IS - 19 A1 - Roberts, C.D. A1 - Waters, J. A1 - Peterson, K.A. A1 - Palmer, M.D. A1 - McCarthy, G.D. A1 - Frajka-Williams, E. A1 - Haines, K. A1 - Lea, D.J. A1 - Martin, M.J. A1 - Storkey, D. A1 - Blockley, E.W. A1 - Zuo, H. Y1 - 2013/10/16/ N2 - The Atlantic meridional overturning circulation (AMOC) has been observed at 26.5°N since 2004. During 2009/2010, there was a transient 30% weakening of the AMOC driven by anomalies in geostrophic and Ekman transports. Here, we use simulations based on the Met Office Forecast Ocean Assimilation Model (FOAM) to diagnose the relative importance of atmospheric forcings and internal ocean dynamics in driving the anomalous geostrophic circulation of 2009/2010. Data-assimilating experiments with FOAM accurately reproduce the mean strength and depth of the AMOC at 26.5°N. In addition, agreement between simulated and observed stream functions in the deep ocean is improved when we calculate the AMOC using a method that approximates the observing array at 26.5°N. The main features of the geostrophic circulation anomaly are captured by an ensemble of simulations without data assimilation. These model results suggest that the atmosphere played a dominant role in driving recent interannual variability of the AMOC. JF - Geophysical Research Letters VL - 40 KW - AMOC KW - variability KW - ocean model KW - data assimilation KW - ocean circulation KW - atlantic meridional overturning circulation SN - 0094-8276 TI - Atmosphere drives recent interannual variability of the Atlantic meridional overturning circulation at 26.5°N SP - 5164 AV - public EP - 5170 ER - TY - JOUR ID - soton360170 UR - https://eprints.soton.ac.uk/360170/ IS - 22 A1 - Roberts, Christopher D. A1 - Garry, Freya K. A1 - Jackson, Laura C. Y1 - 2013/// N2 - The Atlantic meridional overturning circulation (AMOC) is an important component of the North Atlantic climate system. Here, simulations from 10 coupled climate models are used to calculate patterns of sea surface temperature (SST) and subsurface density change associated with decadal AMOC variability. The models are evaluated using observational constraints and it is shown that all 10 models suffer from North Atlantic Deep Water transports that are too shallow, although the biases are least severe in the Community Climate System Model, version 4 (CCSM4). In the models that best compare with observations, positive AMOC anomalies are associated with reduced Labrador Sea stratification and increased midocean (800?1800 m) densities in the subpolar gyre. Maximum correlations occur when AMOC anomalies lag Labrador Sea stratification and subsurface density anomalies by 2?6 yr and 0?3 yr, respectively. In all 10 models, North Atlantic warming follows positive AMOC anomalies, but the patterns and magnitudes of SST change are variable. A simple detection and attribution analysis is then used to evaluate the utility of Atlantic midocean density and Labrador Sea stratification indices for detecting changes to the AMOC in the presence of increasing CO2 concentrations. It is shown that trends in midocean density are identifiable (although not attributable) significantly earlier than trends in the AMOC. For this reason, subsurface density observations could be a useful complement to transport observations made at specific latitudes and may help with the more rapid diagnosis of basin-scale changes in the AMOC. Using existing observations, it is not yet possible to detect a robust trend in the AMOC using either midocean densities or transport observations from 26.5°N. JF - Journal of Climate VL - 26 KW - North Atlantic Ocean KW - Thermohaline circulation KW - Coupled models KW - Climate variability KW - Multidecadal variability KW - Oceanic variability SN - 0894-8755 TI - A Multimodel Study of Sea Surface Temperature and Subsurface Density Fingerprints of the Atlantic Meridional Overturning Circulation SP - 9155 AV - none EP - 9174 ER - TY - JOUR ID - soton44124 UR - https://eprints.soton.ac.uk/44124/ IS - 14-16 A1 - Robinson, C. A1 - Poulton, A.J. A1 - Holligan, P.M. A1 - Baker, A.R. A1 - Forster, G. A1 - Gist, N. A1 - Jickells, T.D. A1 - Malin, G. A1 - Upstill-Goddard, R. A1 - Williams, R.G. A1 - Woodward, E.M.S. A1 - Zubkov, M.V. Y1 - 2006/// N2 - The aims of the Atlantic Meridional Transect (AMT) programme [www.amt-uk.org] are to quantify the nature and causes of ecological and biogeochemical variability in the planktonic ecosystems of the Atlantic Ocean, and to assess the effects of this variability on biological carbon cycling and air?sea exchange of radiatively active gases and aerosols. Marine and atmospheric data have been collected twice a year along a 13,500 km transect in the Atlantic Ocean between 50°N and 52°S since 1995. The cruise track enables biogeochemical measurements to be made within the poorly studied North and South Atlantic oligotrophic gyres as well as within equatorial and coastal upwelling regions. The range of ecosystems sampled during AMT has facilitated the calibration and validation of newly developed optical, microbiological, molecular and analytical techniques and provided a testbed for comparative ecology and the development of atmospheric and oceanographic models. This paper describes the rationale and methodology of the programme. Upper-ocean measurements of density, nitrate and chlorophyll a (Chl a) are presented to illustrate seasonal, inter-annual and decadal variability in hydrography. Seasonal distributions of dissolved nitrous oxide (N2O) and methane (CH4) are used to derive estimates of the sea?air flux of these gases in the South Atlantic Gyre. Observations made during AMT and published since 2000 are reviewed, and the key findings are highlighted. The extent to which the programme aims have been achieved is discussed and improvements for the future suggested.
JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 53 KW - Atlantic Meridional Transect KW - biogeochemistry KW - biodiversity KW - Pelagic ecosystems KW - microbial plankton communities KW - Atlantic Ocean SN - 0967-0645 TI - The Atlantic Meridional Transect (AMT) Programme: a contextual view 1995?2005 SP - 1485 AV - none EP - 1515 ER - TY - JOUR ID - soton59222 UR - https://eprints.soton.ac.uk/59222/ IS - 5 A1 - Robinson, Carol A1 - Serret, Pablo A1 - Tilstone, Gavin A1 - Teira, Eva A1 - Zubkov, Mikhail V. A1 - Rees, Andrew P. A1 - Woodward, E. Malcolm S. Y1 - 2002/05// N2 - Concurrent measurements of dark community respiration (DCR), gross production (GP), size fractionated primary production (14C PP), nitrogen uptake, nutrients, chlorophyll a concentration, and heterotrophic and autotrophic bacterial abundance were collected from the upper 200 m of a latitudinal (32°S?48°N) transect in the Eastern Atlantic Ocean during May/June 1998. The mean mixed layer respiration rate was 2.5±2.1 mmol O2 m?3 d?1 (n=119) for the whole transect, 2.2±1.1 mmol O2 m?3 d?1 (n=32) in areas where chlorophyll a was <0.5 mg m?3 and 1.5±0.7 mmol O2 m?3 d?1 (n=10) where chlorophyll a was <0.2 mg m?3. These values lie within the range of published data collected in comparable waters, they co-vary with indicators of heterotrophic and autotrophic biomass (heterotrophic bacterial abundance, chlorophyll a concentration, beam attenuation and particulate organic carbon concentration) and they can be reconciled with accepted estimates of total respiratory activity. The mean and median respiratory quotient (RQ), calculated as the ratio of dissolved inorganic carbon production to dissolved oxygen consumption, was 0.8 (n=11). At the time of the study, plankton community respiration exceeded GP in the picoautotroph dominated oligotrophic regions (Eastern Tropical Atlantic [15.5°S?14.2°N] and North Atlantic Subtropical Gyre [21.5?42.5°N]), which amounted to 50% of the stations sampled along the 12,100 km transect. These regions also exhibited high heterotrophic: autotrophic biomass ratios, higher turnover rates of phytoplankton than of bacteria and low f ratios. However, the carbon supply mechanisms required to sustain the rates of respiration higher than GP could not be fully quantified. Future research should aim to determine the temporal balance of respiration and GP together with substrate supply mechanisms in these ocean regions. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 49 KW - Plankton KW - Respiration KW - Gross production KW - Net community production KW - Eastern Atlantic Ocean SN - 0967-0637 TI - Plankton respiration in the Eastern Atlantic Ocean SP - 787 AV - none EP - 813 ER - TY - JOUR ID - soton352180 UR - https://eprints.soton.ac.uk/352180/ IS - 5-6 A1 - Rogacheva, Antonina A1 - Gebruk, Andrey A1 - Alt, Claudia H.S. Y1 - 2013/04// N2 - Holothurians are among the most species-rich taxa in the megabenthos on the northern Mid-Atlantic Ridge at depths of 2200?3700 m. Extensive new collections of 32 holothurian species were made in 2007?2010 in the Charlie Gibbs Fracture Zone area as part of the ECOMAR project. New material includes samples taken using a trawl and the ROV Isis. Samples and in situ observations from the ROV were of particular value because the morphological details of a number of holothurian species could be clarified. Many of these species are gelatinous and fragile and were damaged in trawls. Three species of elasipodid holothurians are described as new to science. An annotated check-list of all species of deep-sea holothurians collected in the Charlie Gibbs Fracture Zone area is provided. The checklist includes synonyms, distribution data and morphological descriptions as well as photographs taken in situ and in vivo. Ecological remarks are given for some species. JF - Marine Biology Research VL - 9 KW - Deep-sea holothurians KW - North Atlantic KW - taxonomy KW - diversity KW - benthic fauna SN - 1745-1000 TI - Holothuroidea of the Charlie Gibbs Fracture Zone area, northern Mid-Atlantic Ridge SP - 587 AV - none EP - 623 ER - TY - JOUR ID - soton362314 UR - https://eprints.soton.ac.uk/362314/ A1 - Rogacheva, Antonina A1 - Gebruk, Andrey A1 - Alt, Claudia H.S. Y1 - 2012/// N2 - The ability to swim was recorded in 17 of 32 species of deep-sea holothurians during the RRS James Cook
ECOMAR cruise in 2010 to the Mid-Atlantic Ridge. Holothurians were observed, photographed, and video recorded using the ROV Isis at four sites around the Charlie-Gibbs Fracture Zone at approximate depths of 2,200?2,800 m. For eleven species swimming is reported for the first time. A number of swimming species were observed on rocks, cliffs and steep slopes with taluses. These habitats are unusual for deep-sea holothurians, which are traditionally common on flat areas with soft sediment rich in detritus. Three species were found exclusively on cliffs. Swimming may provide an advantage in cliff habitats that are inaccessible to most epibenthic deposit-feeders. JF - Zoosymposia VL - 7 KW - sea cucumbers KW - benthopelagic species KW - diversity KW - Northern Atlantic Ocean SN - 1178-9905 TI - Swimming deep-sea holothurians (Echinodermata: Holothuroidea) on the northern Mid-Atlantic Ridge SP - 213 AV - restricted EP - 224 ER - TY - JOUR ID - soton342788 UR - https://eprints.soton.ac.uk/342788/ IS - 3-4 A1 - Rogerson, M. A1 - Bigg, G.R. A1 - Rohling, E.J. A1 - Ramirez, J. Y1 - 2012/08// N2 - Past changes in the density and momentum structure of oceanic circulation are an important aspect of changes in the Atlantic Meridional Overturning Circulation and consequently climate. However, very little is known about past changes in the vertical density structure of the ocean, even very extensively studied systems such as the North Atlantic. Here we exploit the physical controls on the settling depth of the dense Mediterranean water plume derived from the Strait of Gibraltar to obtain the first robust, observations-based, probabilistic reconstruction of the vertical density gradient in the eastern North Atlantic during the last 30,000 years. We find that this gradient was weakened by more than 50%, relative to the present, during the last Glacial Maximum, and that changes in general are associated with reductions in AMOC intensity. However, we find only a small change during Heinrich Event 1 relative to the Last Glacial Maximum, despite strong evidence that overturning was substantially altered. This implies that millennial-scale changes may not be reflected in vertical density structure of the ocean, which may be limited to responses on an ocean-overturning timescale or longer. Regardless, our novel reconstruction of Atlantic density structure can be used as the basis for a dynamical measure for validation of model-based AMOC reconstructions. In addition, our general approach is transferrable to other marginal sea outflow plumes, to provide estimates of oceanic vertical density gradients in other locations. JF - Climate Dynamics VL - 39 KW - Atlantic Ocean KW - Meridional overturning KW - Overflow physics KW - Mediterranean outflow KW - Iberian margin KW - Paleoceanography SN - 0930-7575 TI - Vertical density gradient in the eastern North Atlantic during the last 30,000 years SP - 589 AV - none EP - 598 ER - TY - JOUR ID - soton8905 UR - https://eprints.soton.ac.uk/8905/ IS - 1-4 A1 - Rohling, E.J. Y1 - 2000/// N2 - Error propagation is investigated through the only commonly applied technique for reconstruction of paleosalinity, based on oxygen isotope residuals. Although this technique is known to be fairly inaccurate, there remained a need for thorough assessment of confidence limits in a variety of global settings. Here, it is found that a theoretical minimum error bar of between ±0.3? and 0.7? applies to paleosalinity estimates, and that real-life practical limits are rarely better than ±0.6?. Best results are expected in the latitudinal ranges >50°N and >70°S, taking care to avoid the sea?ice margin. Confidence intervals at low and mid-latitudes (including marginal seas) are very wide, at least ±1.8? for the Mediterranean and ±2.2? for the equatorial Atlantic. It appears that oxygen isotope distributions are best used in their own right to investigate circulation and advective processes in coupled ocean?atmosphere?cryosphere models, instead of calibrating them to paleosalinity to define restoring boundary conditions. However, isotope residual-based paleosalinity maps from large numbers of (regionally averaged) studies in the above-mentioned latitudinal bands may help in defining initial conditions and first-order validation arguments for models. JF - Marine Geology VL - 163 KW - SALINITY KW - PALAEOCEANOGRAPHY KW - PALAEOSALINITY KW - OXYGEN ISOTOPES KW - MEDITERRANEAN SEA KW - TROPICAL ATLANTIC OCEAN SN - 0025-3227 TI - Paleosalinity: confidence limits and future applications SP - 1 AV - none EP - 11 ER - TY - JOUR ID - soton68879 UR - https://eprints.soton.ac.uk/68879/ IS - 19-20 A1 - Rona, Peter A. A1 - Seilacher, Adolf A1 - de Vargas, Colomban A1 - Gooday, Andrew J. A1 - Bernhard, Joan M. A1 - Bowser, Sam A1 - Vetriani, Costantino A1 - Wirsen, Carl O. A1 - Mullineaux, Lauren A1 - Sherrell, Robert A1 - Grassle, J. Frederick A1 - Low, Stephen A1 - Lutz, Richard A. Y1 - 2009/09// N2 - We report new in situ observations and laboratory studies of specimens of a small (diameter 2.4?7.5 cm) strikingly hexagonal form originally described from sedimented steps in a wall of the axial valley of the Mid-Atlantic Ridge (water depth 3430?3575 m) near 26°N, 45°W that appears to be identical to the iconic form Paleodictyon nodosum described as a trace fossil from Eocene flysch deposits at sites in Europe and Wales. Our findings follow:
? The form is apparently agglutinated in sea floor sediment (a veneer of calcareous lutite over red metalliferous sediment) and consists of three equidistant rows of tiny holes (diameter 1 mm) that intersect at an angle of 120° and continuously connect through vertical shafts (length 2?3 mm) with an underlying horizontal network of tubes or tunnels identical with the fossil form.
? The number of rows of holes and spacing of rows increase with overall diameter of the form indicative of organic growth.
? The form is shaped like a shield surrounded by a lip and moat with surface relief (0.5 cm) that is absent in the fossil form. The surface relief exposes the underlying red sediment and may have been produced either by excavation (constructional origin) or by infaunal growth (body form).
? Protoplasm is absent in recovered specimens, as indicated by negative results of staining techniques, explained by either initial absence or loss.
? Genetic sequencing of material from the form identified different foraminifera that had settled on the pattern of holes which acts as a baffle to trap organic matter.
? Models in flume tanks show that the shield-like form deflects flow of ocean currents into a self-ventilating structure capable of aerating and of circulating organic particles through the tubes or tunnels.
? Microbial counting techniques indicated background abundances within and outside the form.
We come to two alternative interpretations of the findings resolvable with further studies: ? The modern P. nodosum is a burrow consistent with interpretation of the ancient form as a trace fossil.
? The modern P. nodosum is a compressed form of a hexactinellid sponge adapted to a sedimentary substrate, which means that the ancient form is a body fossil with possible affinity to the Ediacara fauna. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 56 KW - Paleodictyon KW - Living fossil KW - Hexactinellid sponge KW - Mid-Atlantic ridge KW - TAG hydrothermal field KW - Ediacaran period SN - 0967-0645 TI - Paleodictyon nodosum: a living fossil on the deep-sea floor SP - 1700 AV - none EP - 1712 ER - TY - JOUR ID - soton1252 UR - http://www.agu.org/pubs/crossref/2003/1999JC000047.shtml IS - C5 A1 - Roson, G. A1 - Rios, A.F. A1 - Perez, F.F. A1 - Lavin, A. A1 - Bryden, H.L. Y1 - 2003/// N2 - Hydrographic CO2 system data obtained from World Ocean Circulation Experiment (WOCE) transatlantic zonal section A5 across 24.5°N and Florida Straits are described. By combining CO2 measurements with hydrographic velocity calculations, the zonal and vertical variability of meridional fluxes of total alkalinity (TA), total dissolved inorganic carbon (TIC), and anthropogenic CO2 (C) are estimated. The resulting CO2 fluxes are examined in four geostrophic mid-ocean zones as well as in the Gulf Stream flow through Florida Straits and in the surface ageostrophic Ekman flow. This method allows an estimate of the net budgets of these chemical species in the system considering together the Arctic and Atlantic Oceans north of 24.5°N. Taking into account the net flux contribution through Bering Strait, total meridional transports of chemical properties across 24.5°N latitude are also estimated. The slightly divergent net TA budget (-460 ± 200 kmol s-1) suggests that the North Atlantic is a small alkalinity source. The divergent TIC budget (-2430 ± 200 kmol s-1 or -0.92 ± 0.08 GtC yr-1) suggests that the North Atlantic is a source of TIC and therefore a net sink for atmospheric CO2. This value is twice as large as a previous estimation made from a poorly sampled section. Surprisingly, the North Atlantic Ocean appears to act as a net sink of anthropogenic CO2 (+630 ± 200 kmol s-1 or +0.24 ± 0.08 GtC yr-1) and therefore a weak source of anthropogenic CO2 to the atmosphere. Its main contributor is the intense northward flux in the Florida Current (+1280 ± 100 kmol s-1). The calculations imply a divergent inorganic carbon budget of -3060 ± 200 kmol s-1 or -1.16 ± 0.08 GtC yr-1 in preindustrial times (TIC278, when the molar fraction of CO2 in the atmosphere was 278.2 ppm). This means that the North Atlantic would have had a 25% stronger divergence of TIC prior to the beginning of anthropogenic CO2 penetration. JF - Journal of Geophysical Research VL - 108 KW - GEOLOGY KW - CARBON DIOXIDE KW - NORTH ATLANTIC OCEAN KW - FLORIDA STRAIT KW - NUMERICAL ANALYSIS KW - DISSOLVED INORGANIC CARBON KW - CARBON CYCLE SN - 0148-0227 TI - Carbon distribution, fluxes, and budgets in the subtropical North Atlantic Ocean (24.5N) AV - none ER - TY - JOUR ID - soton8861 UR - http://www.ingenta.com/isis/searching/ExpandTOC/ingenta;jsessionid=2ixo4jtbu6j7c.circus?issue=pubinfobike://geol/jgs/2000/00000157/00000003&index=12 IS - 3 A1 - Rothwell, R.G. Y1 - 2000/05// JF - Journal of the Geological Society VL - 157 KW - PALAEOCEANOGRAPHY KW - PALAEOCLIMATE KW - NEAPACC KW - CLIMATIC CHANGE EFFECTS KW - NORTHEAST ATLANTIC OCEAN KW - RESEARCH PROGRAMMES SN - 0016-7649 TI - NE Atlantic palaeoceanography and climatic change AV - none ER - TY - JOUR ID - soton379443 UR - https://eprints.soton.ac.uk/379443/ IS - 8 A1 - Rumyantseva, Anna A1 - Lucas, Natasha A1 - Rippeth, Tom A1 - Martin, Adrian A1 - Painter, Stuart C. A1 - Boyd, Timothy J. A1 - Henson, Stephanie Y1 - 2015/08// N2 - Storms that affect ocean surface layer dynamics and primary production are a frequent occurrence in the open North Atlantic Ocean. In this study we use an interdisciplinary dataset collected in the region to quantify nutrient supply by two pathways associated with a storm event: entrainment of nutrients during a period of high wind forcing and subsequent shear-spiking at the pycnocline due to interactions of storm generated inertial currents with wind. The post-storm increase in surface layer nitrate (by ~20 mmol m?2) was predominantly driven by the first pathway: nutrient intrusion during the storm. Alignment of post-storm inertial currents and surface wind stress caused shear instabilities at the ocean pycnocline, forming the second pathway for nutrient transport into the euphotic zone. During the alignment period, pulses of high turbulent nitrate flux through the pycnocline (up to 1 mmol m?2 day?1; approximately 25 times higher than the background flux) were detected. However, the impact of the post-storm supply was an order of magnitude lower than during the storm due to the short duration of the pulses. Cumulatively, the storm passage was equivalent to 2.5-5 % of the nitrate supplied by winter convection and had a significant effect compared to previously reported (sub)-mesoscale dynamics in the region. As storms occur frequently, they can form an important component in local nutrient budgets. JF - Global Biogeochemical Cycles VL - 29 KW - storms KW - nutrients KW - diapycnal mixing KW - inertial currents KW - North Atlantic Ocean SN - 0886-6236 TI - Ocean nutrient pathways associated with the passage of a storm SP - 1179 AV - public EP - 1189 ER - TY - JOUR ID - soton353520 UR - https://eprints.soton.ac.uk/353520/ A1 - Ryan, C. A1 - McHugh, B. A1 - Trueman, C.N. A1 - Sabin, R. A1 - Deaville, R. A1 - Harrod, C. A1 - Berrow, S.D. A1 - O?Connor, I. Y1 - 2013/// N2 - Stable isotope analysis is a useful tool for investigating diet, migrations and niche in ecological communities by tracing energy through food-webs. In this study, the stable isotopic composition of carbon and nitrogen in keratin was measured at growth increments of baleen plates from 3 sympatric species of rorquals (Balaenoptera acutrostrata, B. physalus and Megaptera novaeangliae), which died between 1985 and 2010 in Irish and contiguous waters. Bivariate ellipses were used to plot isotopic niches and standard ellipse area parameters were estimated via Bayesian inference using the SIBER routine in the SIAR package in R. Evidence of resource partitioning was thus found among fin, humpback and minke whales using isotopic niches. Highest ?15N values were found in minke whales followed by humpback, and fin whales. Comparison between Northeast Atlantic (Irish/UK and Biscayan) and Mediterranean fin whale isotopic niches support the current International Whaling Commission stock assessment of an isolated Mediterranean population. Significantly larger niche area and higher overall ?15N and ?13C values found in fin whales from Irish/UK waters compared to those sampled in adjacent regions (Bay of Biscay and Mediterranean) suggest inshore foraging that may be unique to fin whales in Ireland and the UK. Isotopic profiles support spatial overlap but different foraging strategies between fin whales sampled in Ireland/UK and the Bay of Biscay. Stable isotope analysis of baleen could provide an additional means for identifying ecological units, thus supporting more effective management for the conservation of baleen whales. JF - Marine Ecology Progress Series VL - 479 KW - Diet KW - Isotopic niche KW - Foraging KW - Stock discrimination KW - Northeast Atlantic KW - Bayesian analysis TI - Stable isotope analysis of baleen reveals resource partitioning among sympatric rorquals and population structure in fin whales SP - 251 AV - none EP - 261 ER - TY - JOUR N1 - Funding Information: We thank the captain and crew of the R/V Marcus Langseth and the RRS Discovery and also the scientific technicians. We thank K. Davis for assistance with the schematic in Fig. 8. C.A.R. and N.H. were funded by the Natural Environment Research Council (NE/M003507/1) (PI-LAB) and the European Research Council (GA 638665) (EURO-LAB). J.M.K. was funded by the Natural Environment Research Council (NE/M004643/1). S.C. was funded by the National Science Foundation under grant OCE-1536400 (CA-LAB). D.S. was supported by the Portuguese Science and Technology Foundation (FCT/Funda??o para a Ci?ncia e Tecnologia), under project PTDC/CTA-GEF/30264/2017 and UIDB/50019/2020 ? IDL Funding Information: We thank the captain and crew of the R/V Marcus Langseth and the RRS Discovery and also the scientific technicians. We thank K. Davis for assistance with the schematic in Fig. 8 . C.A.R. and N.H. were funded by the Natural Environment Research Council ( NE/M003507/1 ) (PI-LAB) and the European Research Council ( GA 638665 ) (EURO-LAB). J.M.K. was funded by the Natural Environment Research Council ( NE/M004643/1 ). S.C. was funded by the National Science Foundation under grant OCE-1536400 (CA-LAB). D.S. was supported by the Portuguese Science and Technology Foundation (FCT/Fundação para a Ciência e Tecnologia), under project PTDC/CTA-GEF/30264/2017 and UIDB/50019/2020 ? IDL Publisher Copyright: © 2021 Elsevier B.V. ID - soton449092 UR - https://eprints.soton.ac.uk/449092/ A1 - Rychert, Catherine A. A1 - Tharimena, Saikiran A1 - Harmon, Nicholas A1 - Wang, Shunguo A1 - Constable, Steven A1 - Kendall, J. Michael A1 - Bogiatzis, Petros A1 - Agius, Matthew R. A1 - Schlaphorst, David Y1 - 2021/07/15/ N2 - In plate tectonic theory a weak asthenosphere is required to facilitate the motions of the rigid plates. Partial melt could weaken the mantle, in turn impacting convection, but to date the existence of persistent melt has remained controversial. A wide range of scenarios has been reported in terms of the location, amount and pathways of melt. Here we use data collected by 39 ocean bottom seismometers deployed near the equatorial Mid-Atlantic Ridge on 0 to 80 Myr old seafloor. We calculate S-to-P (Sp) receiver functions and perform waveform modeling. We jointly interpret with shear-wave velocity tomography from surface waves and magnetotelluric (MT) imaging to take advantage of a range of resolutions and sensitivities and illuminate the structure of the oceanic lithosphere and the underlying asthenosphere. We image a tectonic plate thickness that increases with age in one location but undulates in another location. We infer thin and slightly thicker melt channels and punctuated regions of ascending partial melt several hundred kilometers off the ridge axis. This suggests melt persists over geologic timescales, although its character is dynamic, with implications for the lithosphere?asthenosphere boundary (LAB) and the driving forces of the plates. Ascending melt intermittently feeds melt channels at the base of the plate. The associated melt-enhanced buoyancy increases the influence of ridge-push in driving plate motions, whereas the channelized melt reduces the resistance of the plates to motion. Therefore, melt dynamics may play a larger role in controlling plate tectonics than previously thought. JF - Earth and Planetary Science Letters VL - 566 KW - Mid-Atlantic Ridge KW - melt dynamics KW - oceanic lithosphere?asthenosphere boundary KW - plate tectonics KW - receiver functions KW - seismology SN - 0012-821X TI - A dynamic lithosphere?asthenosphere boundary near the equatorial Mid-Atlantic Ridge AV - public EP - 36 ER - TY - JOUR ID - soton359942 UR - https://eprints.soton.ac.uk/359942/ A1 - Rynearson, T.A. A1 - Richardson, K. A1 - Lampitt, R.S. A1 - Sieracki, M.E. A1 - Poulton, A.J. A1 - Lyngsgaard, M.M. A1 - Perry, M.J. Y1 - 2013/12// N2 - The mass sinking of phytoplankton cells following blooms is an important source of carbon to the ocean's interior, with some species contributing more to the flux of particulate organic carbon (POC) than others. During the 2008 North Atlantic Bloom Experiment in the Iceland Basin, we examined plankton community composition from surface waters and from sediment traps at depths down to 750 m. Samples collected with neutrally buoyant Lagrangian sediment traps captured a major flux event. Diatoms comprised ?99% of cell flux into the sediment traps, with vegetative cells and resting spores of the genus Chaetoceros contributing 50?95% of cell flux. Resting spores of one species, identified as Chaetoceros aff. diadema, were dominant, comprising 35?92% of cell flux. The flux of resting spores ranged from 2 to 63 mg C m?2 day?1 and was significantly correlated with POC flux (p=0.003). Over the course of 10 days, the flux of resting spores increased by 26 fold, suggesting that the cells sank en masse, possibly in aggregates. In contrast, vegetative cells of C. aff. diadema sampled from surface waters during the period preceding the flux event generally comprised <1% of the diatom community and never exceeded 5.2%. Resting spores of C. aff. diadema were rarely observed in surface waters but their concentrations increased with depth (to 200 m) below the mixed layer. This increase in resting spore abundance, coupled with increased dissolved silicic acid concentrations at depth, suggest that the morphological changes associated with spore formation may have occurred in the mesopelagic zone, while cells were sinking. The values of variable fluorescence (Fv/Fm) measured on sediment trap material dominated by resting spores were among the highest values measured in the study area at any depth. This, in combination with the rapid germination of resting spores in ship-board incubations, suggests that vegetative cells were not physiologically stressed during spore formation. The degradation-resistant, heavily silicified resting spore valves explain the high relative contribution of C. aff. diadema resting spores to total plankton carbon at depth. These data emphasize the ephemeral nature of organic carbon flux events in the open ocean and highlight how non-dominant species and transient life stages can contribute more to carbon flux than their more abundant counterparts. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 82 KW - Aggregates KW - Carbon flux KW - Chaetoceros KW - Diatom resting spores KW - Floating sediment traps KW - North Atlantic spring bloom SN - 0967-0637 TI - Major contribution of diatom resting spores to vertical flux in the sub-polar North Atlantic SP - 60 AV - none EP - 71 ER - TY - JOUR ID - soton52610 UR - https://eprints.soton.ac.uk/52610/ IS - 5 A1 - Sahu, Sujit K. A1 - Challenor, Peter Y1 - 2008/03// N2 - The world's climate is to a large extent driven by the transport of heat and fresh water in the oceans. Regular monitoring, studying, understanding and forecasting of temperature and salinity at different depths of the oceans are a great scientific challenge. Temperature at the ocean surface can be measured from space. However salinity cannot yet be measured by satellites, and space-based measurements can only ever give us values at the surface. Until recently temperature and salinity measurements within the oceans have had to come from expensive research ships. The Argo float program has been funded by various nations to collect actual measurements and rectify this problem.
A Bayesian hierarchical model is proposed in this paper describing the spatio-temporal behavior of the joint distribution of temperature and salinity levels. The model is obtained as a kernel-convolution effect of a single latent spatio-temporal process. Additional terms in the mean describe non-stationarity arising in time and space. Predictive Bayesian model selection criteria have been used to validate the models using data for the year 2003. Illustrative annual prediction maps along with their uncertainty maps are also obtained. The Markov chain Monte Carlo methods are used throughout in the implementation. JF - Environmetrics VL - 19 KW - hierarchical model KW - markov chain monte carlo KW - non-stationary spatio-temporal process KW - north atlantic KW - oceanography SN - 1180-4009 TI - A space-time model for joint modeling of ocean temperature and salinity levels as measured by Argo floats SP - 509 AV - none EP - 528 ER - TY - JOUR N1 - Funding Information: We acknowledge funding from the National Research Council (NE/M003507/1 and NE/K010654/1) and the European Research Council (GA 638665). Ocean?bottom seismometers were provided by Scripps Institute of Oceanography, Lamont?Doherty Earth Observatory, and the institute de Physique de Globe de Paris. Data can be found from Rychert et al., (2016). The authors would like to thank the crew about the ships RV Marcus G Langseth (MGL1602) and the RRS Discovery (DY072). Funding Information: We acknowledge funding from the National Research Council (NE/M003507/1 and NE/K010654/1) and the European Research Council (GA 638665). Ocean-bottom seismometers were provided by Scripps Institute of Oceanography, Lamont-Doherty Earth Observatory, and the institute de Physique de Globe de Paris. Data can be found from Rychert et al., (2016). The authors would like to thank the crew about the ships RV Marcus G Langseth (MGL1602) and the RRS Discovery (DY072). Publisher Copyright: © 2021. The Authors. Copyright: Copyright 2021 Elsevier B.V., All rights reserved. ID - soton449689 UR - https://eprints.soton.ac.uk/449689/ IS - 3 A1 - Saikia, Utpal A1 - Rychert, Catherine A1 - Harmon, Nicholas A1 - Kendall, J. M. Y1 - 2021/03/01/ N2 -

The evolution of ocean lithosphere and asthenosphere are fundamental to plate tectonics, yet high resolution imaging is rare. We present shear wave velocity and azimuthal anisotropy models for the upper mantle from Rayleigh wave group velocities from local earthquake and ambient noise at 15?40-s period recorded by the Passive Imaging of the Lithosphere Asthenosphere Boundary experiment at the equatorial Mid-Atlantic Ridge covering 0?80-Myr-old seafloor. We find slow velocities along the ridge, with faster velocities beneath older seafloor. We image a fast lid (25?30-km thick) beneath the ridge that increases to 50?60 km beneath older seafloor. Punctuated, ?100 km wide low velocity anomalies exist off-axis. There are multiple layers of azimuthal anisotropy, including (i) a lithosphere (20?40 km depth) characterized by strong anisotropy (4.0%?7.0 %) with fast-axes that rotate from ridge subparallel toward the absolute plate motion/spreading direction at distances >60 km from the ridge, and (ii) weak anisotropy (1.0%?2.0%) at >40 km depth. Our results are consistent with conductive cooling of lithosphere, although with some complexities. Thickened lithosphere beneath the ridge supports lateral conductive cooling beneath slow-spreading centers. Undulations in lithospheric thickness and slow asthenospheric velocities are consistent with small scale convection and/or partial melt. Lithospheric anisotropy can be explained by vertical flow and a contribution from either fluid or mineral filled cracks organized melt beneath the ridge and plate motion induced strain off axis. Deep azimuthal anisotropy is suggestive of upwelling beneath the ridge and three-dimensional flow possibly caused by small scale convection off-axis.

JF - Geochemistry, Geophysics, Geosystems VL - 22 KW - asthenosphere KW - azimuthal anisotropy KW - lithosphere KW - Mid-Atlantic ridge KW - shear wave velocity SN - 1525-2027 TI - Upper mantle anisotropic shear velocity structure at the equatorial mid-atlantic ridge constrained by Rayleigh Wave Group velocity analysis from the PI-LAB experiment AV - none EP - 22 ER - TY - JOUR N1 - Funding Information: We would like to thank the crew about the ships RV Marcus G Langseth (MGL02?16) and the RRS Discovery (DY072). We acknowledge funding from the National Environment Research Council (NE/M003507/1 and NE/M004643/1) and the European Research Council (GA 638,665). Ocean bottom seismometers were provided by Scripps Institute of Oceanography, Lamont?Doherty Earth Observatory, and the institute de Physique de Globe de Paris. Funding Information: We would like to thank the crew about the ships RV Marcus G Langseth (MGL02-16) and the RRS Discovery (DY072). We acknowledge funding from the National Environment Research Council (NE/M003507/1 and NE/M004643/1) and the European Research Council (GA 638,665). Ocean bottom seismometers were provided by Scripps Institute of Oceanography, Lamont-Doherty Earth Observatory, and the institute de Physique de Globe de Paris. Publisher Copyright: © 2021. The Authors. Copyright: Copyright 2021 Elsevier B.V., All rights reserved. ID - soton454106 UR - https://eprints.soton.ac.uk/454106/ IS - 12 A1 - Saikia, Utpal A1 - Rychert, Catherine A. A1 - Harmon, Nicholas A1 - Michael Kendall, J. Y1 - 2021/12/08/ N2 -

The ocean lithosphere represents a simple realisation of the tectonic plate, offering a unique opportunity to better understand its physical and chemical properties in relationship to those of the underlying asthenosphere. While seismic velocity is frequently used to image the plate, seismic attenuation (Q??1) offers an important complimentary observation. We use fundamental mode Rayleigh waves from 17 local, M > 4.2 earthquakes recorded at stations located on 0?80 My old lithosphere near the equatorial Mid-Atlantic Ridge. We determine the attenuation coefficient ((Formula presented.)) for periods between 15 and 40 s and invert for 1-D average shear wave quality factor values ((Formula presented.)) and shear wave velocity (Vs). We find (Formula presented.) values of 175 ± 16 at 50 km depth, decreasing to 90 ± 15 at greater than 60 km. Comparison of our (Formula presented.) and Vs measurements to previous observations from oceanic settings shows agreement in terms of higher (Formula presented.) and Vs in the lithosphere in comparison to the asthenosphere. The observations from oceanic settings are in general agreement with the laboratory predictions for (Formula presented.) -Vs relationships for thermal models. However, a small amount of partial melt (1%) is required to explain several previous observations. Our result also compares favorably to previous observations of lithospheric and asthenospheric attenuation with respect to frequency. Melt is not required for the 1-D average of our study area, consistent with previous electromagnetic and seismic imaging that suggested melt in punctuated and/or thin channel anomalies rather than over broad regions of the mantle.

JF - Geochemistry, Geophysics, Geosystems VL - 22 KW - attenuation KW - Mid Atlantic Ridge KW - surface wave SN - 1525-2027 TI - Seismic attenuation at the equatorial Mid-Atlantic Ridge constrained by local Rayleigh wave analysis from the PI-LAB experiment AV - public EP - 16 ER - TY - JOUR ID - soton44125 UR - https://eprints.soton.ac.uk/44125/ IS - 14-16 A1 - San Martin, E. A1 - Harris, R.P. A1 - Irigoien, X. Y1 - 2006/// N2 - The size distribution of the pelagic community has the potential to compare ecosystems with different species composition as well as to identify the main functional properties of the system. Plankton size spectra are an effective approach of summarising the size structure of the community and have the potential to indicate the transfer of energy up the trophic food web. However, data on which open ocean plankton biomass-size structure can be constructed are scarce. Here we present the latitudinal distribution in the Atlantic Ocean of normalised biomass-size spectra (NB-S), plankton biomass and abundance, as well as mean zooplankton size between 70°N and 50°S. Samples were collected from three Atlantic Meridional Transect (AMT) cruises during May/June 2003, September/October 2003 and April/June 2004, as well as from a Marine Productivity (MarProd) cruise farther north in the Irminger Sea during spring 2002. The biomass-size distribution covered a body size range from nano- to mesoplankton and was based on a depth range of 50?0 m on the AMT and 120?0 m on the Irminger Sea cruise. The distribution of normalised biomass versus size was linear on a double log plot at all of the 95 stations. The slopes of the NB-S spectra ranged from ?0.93 to ?1.26 and ?1.12 to ?1.46 on the AMT and Irminger Sea cruises, respectively. A ?dome-shaped? pattern in the slopes of community size spectra was observed in the Atlantic, indicating a decrease in the trophic transfer efficiency of energy with increasing latitude and phytoplankton biomass. Mesozooplankton biomass, abundance, and mean size followed a distribution similar to ecosystem productivity. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 53 KW - plankton size spectra KW - zooplankton biomass KW - transfer efficiency KW - provinces KW - spatial variability KW - Atlantic Meridional Transect SN - 0967-0645 TI - Latitudinal variation in plankton size spectra in the Atlantic Ocean SP - 1560 AV - none EP - 1572 ER - TY - JOUR ID - soton54872 UR - https://eprints.soton.ac.uk/54872/ IS - 5 A1 - Santos, V.C.L.S. A1 - Billett, D.S.M. A1 - Wolff, G.A. Y1 - 2002/// N2 - A study of the glyceryl ether composition of free lipids of gut walls and contents of an abyssalholothurian species, Oneirophanta mutabilis has been carried out. A series of saturated and unsaturated1-O-alkylglyceryl ethers with alkyl side chains ranging from C15 to C21 were detected in the gut walls and contents of O. mutabilis. Glyceryl ethers accounted for 5-12% of the total free lipids contents. Foregut, midgut and hindgut walls and contents have identical 1-O-alkylglyceryl ether compositions. The C16:0, C16:1, C17:0, C18:0 and C18:1 are the main glyceryl ethers with C18:0 being dominant. The total organic carbon (TOC) and nitrogen (N) contents were also evaluated in gut contents of the digestive tract of O. mutabalis and these decreased from foregut to hindgut. The average assimilation efficiencies were estimated to be 40 and 55% for TOC and N respectively. JF - Journal of the Brazilian Chemical Society VL - 13 KW - 1-O-alkylglyceryl ether KW - abyssal sediment KW - holothurian KW - Oneirophanta mutabilis KW - Atlantic Ocean SN - 0103-5053 TI - 1-O-Alkylglyceryl ether lipids of the gut walls and contents of an abyssal holothurian (Oneirophanta mutabilis) SP - 653 AV - public EP - 657 ER - TY - JOUR ID - soton381916 UR - https://eprints.soton.ac.uk/381916/ IS - 10 A1 - Sarkar, S. A1 - Sheen, K.L. A1 - Klaeschen, D. A1 - Brierley, J.A. A1 - Minshull, T.A. A1 - Berndt, C. A1 - Hobbs, R.W. A1 - Naveira Garabato, A.C. Y1 - 2015/10// N2 - The West Spitsbergen Current, which flows northward along the western Svalbard continental slope, transports warm and saline Atlantic water (AW) into the Arctic Ocean. A combined analysis of high-resolution seismic images and hydrographic sections across this current has uncovered the oceanographic processes involved in horizontal and vertical mixing of AW. At the shelf break, where a strong horizontal temperature gradient exists east of the warmest AW, isopycnal interleaving of warm AW and surrounding colder waters is observed. Strong seismic reflections characterize these interleaving features, with a negative polarity reflection arising from an interface of warm water overlying colder water. A seismic-derived sound speed image reveals the extent and lateral continuity of such interleaving layers. There is evidence of obliquely aligned internal waves emanating from the slope at 450?500 m. They follow the predicted trajectory of internal S2 tidal waves and can promote vertical mixing between Atlantic- and Arctic-origin waters. JF - Journal of Geophysical Research: Oceans VL - 120 KW - Seismic oceanography KW - Svalbard KW - Atlantic water KW - Polar water KW - Thermohaline interleaving KW - Internal wave SN - 2169-9275 TI - Seismic reflection imaging of mixing processes in Fram Strait SP - 6884 AV - public EP - 6896 ER - TY - JOUR ID - soton49866 UR - https://eprints.soton.ac.uk/49866/ IS - 3-4 A1 - Sarthou, G. A1 - Baker, A.R. A1 - Kramer, J. A1 - Laan, P. A1 - Laes, A. A1 - Ussher, S. A1 - Achterberg, E.P. A1 - de Baar, H.J.W. A1 - Timmermans, K.R. A1 - Blain, S. Y1 - 2007/03/21/ N2 - Aerosol (soluble and total) iron and water-column dissolved (DFe, < 0.2 ?m) and total dissolvable (TDFe, unfiltered) iron concentrations were determined in the Canary Basin and along a transect towards the Strait of Gibraltar, in order to sample across the Saharan dust plume. Cumulative dust deposition fluxes estimated from direct aerosol sampling during our one-month cruise are representative of the estimated deposition fluxes based on near surface water dissolved aluminium concentrations measured on board. Iron inventories in near surface waters combined with flux estimates confirmed the relatively short residence time of DFe in waters influenced by the Saharan dust plume (6?14 months). Enhanced near surface water concentrations of DFe (5.90?6.99 nM) were observed at the Strait of Gibraltar mainly due to inputs from metal-rich rivers. In the Canary Basin and the transect towards Gibraltar, DFe concentrations (0.07?0.76 nM) were typical of concentrations observed in the surface North Atlantic Waters, with the highest concentrations associated with higher atmospheric inputs in the Canary Basin. Depth profiles showed that DFe and TDFe were influenced by atmospheric inputs in this area with an accumulation of aeolian Fe in the surface waters. The sub-surface minimum of both DFe and TDFe suggests that a simple partitioning between dissolved and particulate Fe is not obvious there and that export may occur for both phases. At depths of around 1000?1300 m, both regeneration and Meddies may explain the observed maximum. Our data suggest that, in deep waters, higher particle concentrations likely due to dust storms may increase the scavenging flux and thus decrease DFe concentrations in deep waters.
JF - Marine Chemistry VL - 104 KW - Dissolved iron KW - Total dissolvable iron KW - Aerosol deposition KW - Solubility KW - Scavenging KW - Regional terms: North-East Atlantic KW - Canary Basin KW - Madeira KW - Gibraltar SN - 0304-4203 TI - Influence of atmospheric inputs on the iron distribution in the subtropical North-East Atlantic Ocean SP - 186 AV - none EP - 202 ER - TY - GEN ID - soton434008 UR - https://eprints.soton.ac.uk/434008/ A1 - Sawyer, Dale S. A1 - Reston, Tim A1 - Minshull, Timothy A1 - Klaeschen, Dirk A1 - Ranero, Cesar A1 - Shillington, Donna A1 - Morgan, Julia K. Y1 - 2018/// N2 - A cooperative project between the U.S., U.K., Germany, Spain, and Portugal, this 2013 two-ship seismic experiment surveyed the Galicia Bank region off Iberia. F.S. Poseidon tended the OBS instruments while R/V Marcus G. Langseth fired the airguns. The goal was to collect data necessary to study the rifted continental to oceanic crust transition in the Deep Galicia Basin west of Spain. Workstation Loading Information (mgl1307.procInfo.pdf), rms velocity field (mgl1307.PSTM_Rms.segy) and eta parameter for VTI anisotropy (mgl1307.PSTM_Eta.segy) are available as a Related Documents. Funding was provided by the U.S. NSF (grants OCE10-31769, OCE10-30650, and OCE10-31769), the U.K. Natural Environmental Research Council (grants (NE/E016502/1 and NE/E015883/1), and the GEOMAR Helmholtz Centre for Ocean Research. PB - Interdisciplinary Earth Data Alliance (IEDA) KW - Iberia KW - passive margin KW - rifting KW - S reflector KW - Peridotite Ridge KW - Continental Margin KW - Oceans KW - Seismic Reflection KW - Marine Geoscience KW - MGL1307 KW - Solid Earth KW - Seismic:Active:MCS-3D:Processed KW - Marcus G. Langseth KW - Atlantic Ocean KW - Continental Rift TI - Processed Multi-Channel Seismic Data from the Galicia S Detachment, Northern Atlantic Ocean, acquired during the R/V Marcus G. Langseth expedition MGL1307 (2013) AV - none ER - TY - JOUR ID - soton46720 UR - https://eprints.soton.ac.uk/46720/ IS - 5-7 A1 - Schiebel, R. A1 - Barker, S. A1 - Lendt, R. A1 - Thomas, H. A1 - Bollmann, J. Y1 - 2007/06// N2 - Calcite dissolution of planktic foraminifers that settle from the surface ocean to depths has been assessed using the weight/size relationship of tests and correlated to carbonate ion concentration ð½CO2 3 Þ of ambient sea water. Globigerina bulloides and Globigerinita glutinata were sampled from the North Atlantic and the Arabian Sea during different seasons (spring and fall and the monsoons, respectively). Test weight has been determined for single tests from narrow size classes (250 8 mm and 300 7 mm minimum test diameter). Initial test weight of both species in surface waters differs between regions and seasons. Weight loss of settling tests in the twilight zone between 100 and 1000m water depths averaged 19%. Below the twilight zone (1000?2500 m) no weight loss occurs on average, and tests may even gain weight. Remineralization of settling planktic foraminiferal tests is most pronounced at maximum DCO2 3 . Accordingly, strong dissolution occurs in the twilight zone, at the depth of maximum decrease in DCO2 3 . It is assumed that dissolution of planktic foraminiferal calcite is caused by CO2 3 (under-) saturation inside the test, buffered by diffusive exchange of CO2 3 ions with the ambient sea water through the pores and aperture. Consequently, reconstruction of small-scale differences in seawater ½CO2 3 from test weight alone is not feasible and systematic correlation between test weight and DCO2 3 of the ambient sea water is statistically not significant. At constant ½CO2 3 , remineralization cannot be deduced from test weight, neither at high nor low CO2 3 saturation. In total, our data suggest that the global vertical planktic foraminiferal CaCO3 flux is about 19% lower than calculated by Schiebel [2002]. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 54 KW - Calcite dissolution KW - Chemical oceanography KW - Sedimentation KW - Paleoceanography KW - North Atlantic KW - Arabian Sea SN - 0967-0645 TI - Planktic foraminiferal dissolution in the twilight zone SP - 676 AV - none EP - 686 ER - TY - JOUR ID - soton35586 UR - https://eprints.soton.ac.uk/35586/ IS - 1-3 A1 - Schiebel, R. A1 - Schmuker, B. A1 - Alves, M. A1 - Hemleben, C. Y1 - 2002/// N2 - South of the Azores Islands, the population dynamics and sedimentation of planktic foraminifers are significantly influenced by the hydrography of the Azores Front Current System (AFCS). Planktic foraminifers collected from the water column during seasonal cruises across the Azores Front, record the temporal and spatial scale of hydrographic and faunal dynamics within this area. Surface sediment analysis reveals the presence of a large number of pteropod shells indicating preservation of aragonite and, therefore, little alteration of the calcitic foraminiferal tests. Consequently, most of the seasonal and spatial variability of the Azores Front is expected to be recorded by the planktic foraminiferal assemblages present within the surface sediment. In particular, Globorotalia scitula, a subsurface-dwelling species, decreases significantly in abundance to the south of the Azores Front, and shows fine-scale changes at the glacial/interglacial time scale. Enhanced faunal proportions of G. scitula in a sediment core that is located to the south of the modern Azores Current indicate a southward shift of the Azores Front Current System during the glacials and the presence of a transitional water mass at the Azores region.
JF - Journal of Marine Systems VL - 37 KW - Micropalaeontology KW - Faunal analysis KW - Planktic foraminifers KW - Lysocline KW - Oceanic fronts KW - Paleoceanography KW - North Atlantic KW - Azores SN - 0924-7963 TI - Tracking the Recent and late Pleistocene Azores front by the distribution of planktic foraminifers SP - 213 AV - none EP - 227 ER - TY - JOUR ID - soton437497 UR - https://eprints.soton.ac.uk/437497/ A1 - Schillereff, D.N. A1 - Chiverrell, R.C. A1 - Macdonald, N. A1 - Hooke, J.M. A1 - Welsh, K. E. A1 - Piliposian, G. A1 - Croudace, I.W. Y1 - 2019/11/01/ N2 -

Concern is growing that climate change may amplify global flood risk but short hydrological data series hamper hazard assessment. Lake sediment reconstructions are capturing a fuller picture of rare, high-magnitude events but the UK has produced few lake palaeoflood records. We report the longest lake-derived flood reconstruction for the UK to date, a 1500-year record from Brotherswater, northwest England. Its catchment is well-suited physiographically to palaeoflood research, but its homogeneous, dark brown sediment matrix precludes visual identification of flood layers. Instead, an outlier detection routine applied to high-resolution particle size measurements showed a >90% match, in stratigraphic sequence, to measured high river flows. Our late-Holocene palaeoflood reconstruction reveals nine multi-decadal periods of more frequent flooding (510?630 CE, 890?960, 990?1080, 1470?1560, 1590?1620, 1650?1710, 1740?1770, 1830?1890 and 1920?2012), and these show a significant association with negative winter North Atlantic Oscillation (wNAO) phasing and some synchrony with solar minima. These flood-rich episodes also overlap with local and regional land-use intensification, which we propose has amplified the flood signal by creating a more efficient catchment sediment conveyor and more rapid hillslope-channel hydrological connectivity. Disentangling anthropogenic and climatic drivers is a challenge but anthropogenic landscape transformation should evidently not be underestimated in palaeoflood reconstructions. Our paper also demonstrates that flood histories can be extracted from the numerous lakes worldwide containing organic-rich, visually homogeneous sediments. This transformative evidence base should lead to more reliable assessments of flood frequency and risks to ecosystems and infrastructure.

JF - Global and Planetary Change VL - 182 KW - Flood hazard KW - Human activity KW - Lake sediments KW - North Atlantic Oscillation KW - Paleofloods KW - Solar forcing SN - 0921-8181 TI - Convergent human and climate forcing of late-Holocene flooding in Northwest England AV - none ER - TY - JOUR ID - soton476779 UR - https://eprints.soton.ac.uk/476779/ IS - 2 A1 - Schlaphorst, David A1 - Rychert, Catherine A. A1 - Harmon, Nicholas A1 - Hicks, Stephen P. A1 - Bogiatzis, Petros A1 - Kendall, J-Michael A1 - Abercrombie, Rachel E. N2 - Seismicity along transform faults provides important constraints for our understanding of the factors that control earthquake ruptures. Oceanic transform faults are particularly informative due to their relatively simple structure in comparison to their continental counterparts. The seismicity of several fast-moving transform faults has been investigated by local networks, but as of today there been few studies of transform faults in slow spreading ridges. Here, we present the first local seismicity catalogue based on event data recorded by a temporary broad-band network of 39 ocean?bottom seismometers located around the slow-moving Chain Transform Fault (CTF) along the Mid-Atlantic Ridge (MAR) from 2016 to 2017 March. We locate 972 events in the area by simultaneously inverting for a 1-D velocity model informed by the event P- and S-arrival times. We refine the depths and focal mechanisms of the larger events using deviatoric moment tensor inversion. Most of the earthquakes are located along the CTF (700) and Romanche transform fault (94) and the MAR (155); a smaller number (23) can be observed on the continuing fracture zones or in intraplate locations. The ridge events are characterized by normal faulting and most of the transform events are characterized by strike-slip faulting, but with several reverse mechanisms that are likely related to transpressional stresses in the region. CTF events range in magnitude from 1.1 to 5.6 with a magnitude of completeness around 2.3. Along the CTF we calculate a b-value of 0.81 ± 0.09. The event depths are mostly shallower than 15 km below sea level (523), but a small number of high-quality earthquakes (16) are located deeper, with some (8) located deeper than the brittle-ductile transition as predicted by the 600?°C-isotherm from a simple thermal model. The deeper events could be explained by the control of sea water infiltration on the brittle failure limit. VL - 234 TI - Local seismicity around the Chain Transform Fault at the Mid-Atlantic Ridge from OBS observations AV - public EP - 1124 N1 - DS would like to acknowledge the financial support FCT through project UIDB/50019/2020?IDL. CAR and NH acknowledge funding from from the Natural Environment Research Council (NE/M003507/1), and the European Research Council (GA 638665). CAR acknowledges funding from from the National Science Foundation (NSF-EAR-2147918). J-MK was funded by the Natural Environment Research Council (NE/M004643/1). Y1 - 2023/03/24/ JF - Geophysical Journal International KW - Atlantic Ocean KW - Mid-ocean ridge processes KW - Oceanic transform and fracture zone processes KW - Seismicity and tectonics SN - 0956-540X SP - 1111 ER - TY - JOUR ID - soton356950 UR - https://eprints.soton.ac.uk/356950/ IS - 8-10 A1 - Schuster, U. A1 - Watson, A.J. A1 - Bates, N.R. A1 - Corbiere, A. A1 - Gonzalez-Davila, M. A1 - Metzl, N. A1 - Pierrot, D. A1 - Santana-Casiano, M. Y1 - 2009/04// N2 - We examine observations from 1990 to 2006 from four voluntary observing ships and two time-series stations in the North Atlantic, fitting a sinusoidal annual cycle and linear year-on-year trend at all locations where there are sufficient data. Results show that in the subtropical regions, sea-surface fCO2 has closely followed the increasing trend in atmospheric fCO2. In contrast, farther north, sea-surface fCO2 has increased faster than fCO2 in the atmosphere. The resulting ?fCO2, driving air?sea flux of CO2, has therefore decreased in the North Atlantic, particularly at higher latitudes, as has the annual mean air?sea flux. Several underlying causes may have led to the observed changes in sea-surface fCO2. Low-frequency modes, such as the North Atlantic Oscillation, lead to changes in the sea-surface temperature, in sea-surface circulation and in vertical mixing, affecting sea-surface fCO2 through biogeochemical processes. A comparison with measurements covering a longer time period shows that the sea-surface fCO2 rise has accelerated since 1990 in the northern North Atlantic. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 56 KW - Carbon dioxide KW - Sea surface KW - North Atlantic KW - Temporal variations KW - Sea?air flux of CO2 SN - 0967-0645 TI - Trends in North Atlantic sea-surface fCO2 from 1990 to 2006 SP - 620 AV - none EP - 629 ER - TY - JOUR ID - soton389596 UR - https://eprints.soton.ac.uk/389596/ A1 - Sear, D. A. A1 - Jones, J. I. A1 - Collins, A. L. A1 - Hulin, A. A1 - Burke, N. A1 - Bateman, S. A1 - Pattison, I. A1 - Naden, P. S. Y1 - 2016/01/15/ N2 - Fine sediments are known to be an important cause of increased mortality in benthic spawning fish. To date, most of the research has focussed on the relationship between embryo mortality and the quantity of fine sediment accumulated in the egg pocket. However, recent evidence suggests a) that the source of fine sediment might also be important, and b) that fitness of surviving embryos post-hatch might also be impacted by the accumulation of fine sediments. In this paper, we report an experiment designed to simulate the incubation environment of brown trout (Salmo trutta) and Atlantic salmon (Salmo salar). During the experiment, the incubating embryos were exposed to different quantities of fine (< 63 ?m) sediment derived from four different sources; agricultural topsoils, damaged road verges, eroding river channel banks and tertiary level treated sewage. Results showed that mass and source are independently important for determining the mortality and fitness of alevin. Differences between species were observed, such that brown trout are less sensitive to mass and source of accumulated sediment. We demonstrate for the first time that sediment source is an additional control on the impact of fine sediment, and that this is primarily controlled by the organic matter content and oxygen consumption of the catchment source material. JF - Science of the Total Environment VL - 541 KW - Sediment sources KW - Brown trout KW - Atlantic salmon KW - Fine sediment KW - Organic matter SN - 0048-9697 TI - Does fine sediment source as well as quantity affect salmonid embryo mortality and development? SP - 957 AV - none EP - 968 ER - TY - JOUR ID - soton348140 UR - https://eprints.soton.ac.uk/348140/ IS - 1 A1 - Sear, David A. A1 - Pattison, Ian A1 - Collins, Adrian L. A1 - Newson, Malcolm D. A1 - Jones, J.I. A1 - Naden, P.S. A1 - Carling, P.A. Y1 - 2014/01// N2 - Dissolved oxygen (DO) plays a critical role in the development of the juvenile stages of benthic spawning fish and salmonids in particular. Factors influencing the DO regime within spawning gravels include the accumulation of fine sediment, penetration of groundwater or surface water into the gravels, thermal regime, and the consumption of oxygen by sediment and its associated organic fractions. In this field study, we quantify the DO regime within an artificial salmon redd at high temporal resolution. The environment within the redd is shown to be complex, with large variations in DO. Application of a numerical model (SIDO-UK) enables for the first time, the quantification of the relative contributions to DO consumption from thermal regime, sediment accumulation and sediment oxygen demand. Sediment accumulation is shown to have a minor impact on DO in the redd whereasupwelling groundwater is identified as the most likely cause of the major changes in DO. Bed mobility has a minor impact on DOregime of the redd. The effects of fine sediment and oxygen supply on salmon embryo survival are estimated. Implications for river catchment management and prospects for future research are discussed JF - Hydrological Processes VL - 28 KW - fine sediments KW - groundwater KW - atlantic salmon KW - dissolved oxygen KW - bed mobility KW - sido-uk model SN - 1099-1085 TI - Factors controlling the temporal variability in dissolved oxygen regime of salmon spawning gravels SP - 83 AV - restricted EP - 103 ER - TY - JOUR ID - soton2113 UR - https://eprints.soton.ac.uk/2113/ IS - 18 Supplement A1 - Severmann, S. A1 - German, C.R. A1 - Edmonds, H.N. A1 - Beard, B.L. A1 - Johnson, C.M. Y1 - 2003/// JF - Geochimica et Cosmochimica Acta VL - 67 KW - IRON ISOTOPES KW - HYDROTHERMAL SOLUTIONS KW - SERPENTINIZATION KW - MID ATLANTIC RIDGE KW - RAINBOW HYDROTHERMAL FIELD SN - 0016-7037 TI - The modification of hydrothermal Fe-isotopic signature during plume-processes (abstract of paper presented at 13th Annual V.M. Goldschmidt Conference, Kurashiki, Japan, September 7-12, 2003) AV - none ER - TY - JOUR ID - soton6105 UR - https://eprints.soton.ac.uk/6105/ A1 - Sexton, P. A1 - Norris, R. Y1 - 2002/// JF - Newsletter of Micropalaeontology VL - No. 66 KW - SPECIES DIVERSITY KW - TAXA KW - ABUNDANCE KW - SPECIES EXTINCTION KW - ATLANTIC OCEAN KW - BIOGEOGRAPHY KW - BIOLOGY KW - GEOLOGY TI - Orbital control of late Pliocene planktonic foraminiferal biogeographic patterns SP - 18 AV - none EP - 19 ER - TY - JOUR ID - soton201407 UR - https://eprints.soton.ac.uk/201407/ IS - 9 A1 - Sheen, Katy L. A1 - White, Nicky A1 - Caulfield, C.P. A1 - Hobbs, Richard W. Y1 - 2011/09// N2 - It is shown that geostrophic vertical shear estimates can be recovered from seismic (i.e., acoustic) images of thermohaline structure. In the Southern Ocean, the Antarctic Circumpolar Current forms a loop within the Falkland Trough before it flows northward into the Argentine Basin. Seismic profiles that cross this loop show the detailed structure of different water masses with a horizontal resolution of O(10 m). Coherent seismic reflections are tilted in response to current flow around the Falkland Trough. Average slopes were measured on length scales that are large enough to ensure that the geostrophic approximation is valid (i.e., with a Rossby number <0.1). By combining shear estimates with satellite altimetric measurements and acoustic Doppler current profiles, geostrophic velocities can be calculated throughout the data volume. This technique for estimating geostrophic vertical shear from legacy seismic images yields useful information about the spatial and temporal variation of mesoscale circulation. JF - Journal of Atmospheric and Oceanic Technology VL - 28 KW - South Atlantic Ocean KW - Baroclinic flows KW - Currents KW - Ocean dynamics KW - Diapycnal mixing KW - Acoustic measurements/effects SN - 0739-0572 TI - Estimating Geostrophic Shear from Seismic Images of Oceanic Structure* SP - 1149 AV - none EP - 1154 ER - TY - JOUR ID - soton1960 UR - http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v425/n6954/full/425125a_fs.html IS - 6954 A1 - Shepherd, J. Y1 - 2003/// JF - Nature VL - 425 KW - ATLN KW - NORTH ATLANTIC OCEAN KW - FISHERIES KW - BIOMASS KW - FISHERY MANAGEMENT KW - FOOD WEB KW - BIOLOGY KW - RESOURCES SN - 0028-0836 TI - Book review: Overfishing in the North Atlantic Ocean has left fish stocks in peril. (In a Perfect ocean, D.Pauly & J. Maclean. Island Press, 2003. 175pp.) SP - 125 AV - none EP - 126 ER - TY - JOUR ID - soton336546 UR - https://eprints.soton.ac.uk/336546/ IS - 5 A1 - Sherwin, Toby J. A1 - Read, Jane F. A1 - Holliday, N. Penny A1 - Johnson, C. Y1 - 2012/07// N2 - Regular time-series of temperature and salinity in the upper waters of the northern Rockall Trough can be traced back to 1948, when Ocean Weather Ships on passage to the west began to record them. Since 1975, these data have been complemented by, then replaced by, dedicated Conductivity, Temperature, and Depth sections along 57.5°N. Today, they are enhanced with real-time observations of the upper 1000 m made by an underwater glider. Since 1995, there has been a steady increase in both temperature (from 9.1 to 10°C) and salinity (from 35.32 to 35.41) as the Subpolar Gyre has retreated west. The historical record suggests that such increases could be compatible with decadal scales of natural variability. Nutrient (nitrate, phosphate, and silicate) concentrations have been measured systematically since 1996 and exhibit interannual variability, particularly in nitrate, the causes of which are not immediately clear. Average phosphate concentrations in the upper 800 m declined from 0.80 to 0.63 ?M by 2009, consistent with the recent incursion of depleted Subtropical Gyre water. The Ellett Line dataset contains a unique and essential archive of observations that can be used to place in context the recent changes in local ocean climate. JF - ICES Journal of Marine Science VL - 69 KW - North Atlantic Gyres KW - nutrients KW - physical oceanography KW - regional climate change KW - Rockall Trough SN - 1054-3139 TI - The impact of changes in North Atlantic Gyre distribution on water mass characteristics in the Rockall Trough SP - 751 AV - restricted EP - 757 ER - TY - JOUR ID - soton188503 UR - https://eprints.soton.ac.uk/188503/ IS - 1485 A1 - Sims, D.W. A1 - Genner, M.J. A1 - Southward, A.J. A1 - Hawkins, S.J. Y1 - 2001/// JF - Proceedings of the Royal Society B: Biological Sciences VL - 268 KW - phenology KW - sea temperature KW - North Atlantic oscillation KW - loliginid squid SN - 0962-8452 TI - Timing of squid migration reflects North Atlantic climate variability SP - 2607 AV - none EP - 2611 ER - TY - JOUR ID - soton357252 UR - https://eprints.soton.ac.uk/357252/ A1 - Singh, Arvind A1 - Lomas, M.W. A1 - Bates, N.R. Y1 - 2013/09// N2 - The average oceanic nitrate-to-phosphate molar ratio (NO3?:PO43??16:1, referred to as the Redfield Ratio) in subsurface waters, which is similar to the average ratio of particulate nitrogen (N)-to-phosphorus (P) in phytoplankton, is the cornerstone in calculating geochemical estimates of N2 fixation and denitrification rates. Any deviations from this canonical Redfield Ratio in intermediate ocean waters, expressed as N* (a measure of NO3? in excess or deficit of 16×PO43?), provides an integrated estimate of net N fluxes into and out of the ocean. In well-oxygenated ocean basins such as the North Atlantic Ocean, N* estimates are usually positive and can be used to infer that rates of N2 fixation exceed rates of denitrification. We use this approach to estimate N2 fixation over the last two decades (1988?2009) based on data collected at the Bermuda Atlantic Time-series Study (BATS) site in the North Atlantic Ocean near Bermuda. Our results indicate that interpretation of the N* tracer as an estimate of N2 fixation should be undertaken with caution, as N2 fixation is not the only process that results in a positive N* estimate. The impacts of a locally variable nitrogen-to-phosphorus ratio, relative to the fixed Redfield Ratio, in the suspended particulate matter as well as in the subsurface water nutrients and atmospheric N deposition on N* variability were examined. Furthermore, we explored the role of climate modes (i.e., North Atlantic Oscillation and Arctic Oscillation) on N* variability. We found that N* in the subsurface waters was significantly affected by these factors and hence previous estimates of N2 fixation using this technique might have been substantially overestimated. Our revised estimate of N2 fixation in the North Atlantic Ocean (0°N?50°N, 20°W?80°W) is 12.2±0.9×1011 mol N yr?1, and based on long-term BATS data provides better constraints than both earlier indirect and direct estimates N2 fixation. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 93 KW - Nitrogen KW - Phosphorus KW - Redfield Ratio KW - N* KW - Geochemical estimates KW - N2 fixation KW - North Atlantic Ocean SN - 0967-0645 TI - Revisiting N2 fixation in the North Atlantic Ocean: Significance of deviations from the Redfield Ratio, atmospheric deposition and climate variability SP - 148 AV - none EP - 158 ER - TY - JOUR ID - soton346905 UR - https://eprints.soton.ac.uk/346905/ IS - 1 A1 - Sinha, Bablu A1 - Topliss, Brenda A1 - Blaker, Adam Tobias A1 - Hirschi, Joel Jean-Marie Y1 - 2013/01// N2 - We investigate processes leading to uncertainty in forecasts of the Atlantic meridional overturning circulation (AMOC). A climate model is used to supply initial conditions for ensemble simulations in which members initially have identical ocean states but perturbed atmosphere states. Baroclinic transports diverge on interannual timescales even though the ocean is not eddy-permitting. Interannual fluctuations of the model AMOC in the subtropical gyre are caused by westward propagating Rossby waves. Divergence of the predicted AMOC with time occurs because the waves develop different phases in different ensemble members predominantly due to differences in eastern boundary windstress curl. These windstress fluctuations communicate with interior ocean transports via modifications to the vertical velocity and the vortex stretching term dw/dz. Consequently, errors propagate westwards resulting in longer predictability times in the interior ocean compared with the eastern boundary. Another source of divergence is transport anomalies propagating along the Gulf Stream (and other boundary currents). The propagation mechanism seems to be predominantly advection by mean currents, and we show that the arrival of westward propagating waves can trigger development of these anomalies. The mean state of the AMOC has a small effect on interannual predictability in the subtropical gyre, most likely because eastern boundary windstress curl predictability is not strongly dependent on the state of the AMOC in the subtropics. Eastern boundary windstress curl was more predictable at 45{degree sign}N when the AMOC was in a strongly decreasing state, but, unlike at 30{degree sign}N, no mechanism was found linking windstress curl fluctuations with deep transports. JF - Journal of Geophysical Research VL - 118 KW - Atlantic meridional overturning circulation KW - predictability KW - Rossby waves SN - 0148-0227 TI - A numerical model study of the effects of interannual timescale wave propagation on the predictability of the Atlantic meridional overturning circulation SP - 131 AV - public EP - 146 ER - TY - RPRT ID - soton41789 UR - https://eprints.soton.ac.uk/41789/ A1 - Sinha, M.C. A1 - Dzhatieva, Z. A1 - Dias, A. A1 - Frerichs, N. Y1 - 2006/// N2 - Charles Darwin 167 (CD167) was a joint research project carried out by UK and Portuguese scientists from the National Oceanography Centre, Southampton, the University of Durham and the University of Lisbon. The task of CD167 was to carry out geophysical and geological studies at the Mid-Atlantic Ridge. The work area was a ridge offset centred on 36º 34? N, 33º 26? W - about 200 n.m. south of the island of Flores in the Azores. At this location, the median valley of the ridge is offset by about 20 km right-laterally, forming a non-transform discontinuity. Of particular interest is a site known as the Saldanha Massif, where previous studies have revealed an area of exposed, tectonically-unroofed mantle rocks and unexpectedly significant hydrothermal circulation with venting near the summit of the massif.

A three-dimensional controlled source electromagnetic (CSEM) survey of sub-sea-floor electrical resistivity was carried out over a 10 km2 area centred on the Saldanha Massif. Following CSEM data analysis, the resulting images of electrical structure will be translated into constraints on porosity distribution, interconnectedness and pore fluid properties by means of geophysical effective medium modelling methods. This in turn will address the questions of whether the Saldanha vent site owes its existence to the presence of a deep fracture network, whether this network completely penetrates the thin crustal carapace within the ridge offset, and how far it extends downwards into the underlying mantle rocks.

A secondary objective was to collect a series of ridge-perpendicular (approximately east-west) profiles of bathymetry and of gravity and magnetic anomalies, to contribute to regional tectonic studies through improving an international European compilation of such data. This was successfully achieved, and the data have been passed on to our international collaborators. A third objective was to collect sea bottom geological samples, by gravity coring and dredging, for analysis at CREMINER in Lisbon. This objective was also achieved. PB - National Oceanography Centre T3 - 4 KW - Charles Darwin KW - cruise 167 2004 KW - Mid-Atlantic Ridge KW - Saldanha Seamount M1 - project_report TI - RRS Charles Darwin Cruise 167, 23 Nov - 21 Dec 2004. Sub-seafloor physical properties at Saldanha Seamount, Mid-Atlantic Ridge, and controls on the spatial distribution of hydrothermal venting AV - public EP - 43 ER - TY - JOUR ID - soton457128 UR - https://eprints.soton.ac.uk/457128/ IS - 6 A1 - Skliris, Nikolaos A1 - Marsh, Robert A1 - Addo, Kwasi Appeaning A1 - Oxenford, Hazel A. N2 -

Since 2011, unprecedented pelagic sargassum seaweed blooms have occurred across the tropical North Atlantic, with severe socioeconomic impacts for coastal populations. To investigate the role of physical drivers in post-2010 sargassum blooms in the Central West Atlantic (CWA), conditions are examined across the wider tropical North Atlantic, using ocean and atmospheric re-analyses and satellite-derived datasets. Of particular consequence for the growth and drift of sargassum are patterns and seasonality of winds and currents. Results suggest that in years of exceptionally large sargassum blooms (2015, 2018), the Intertropical Convergence Zone (ITCZ), an area of maximum wind convergence where sargassum naturally accumulates, shifted southward, towards nutrient-rich waters of the Amazon River plume and the equatorial upwelling zone further stimulating sargassum growth. These changes are associated with modes of natural variability in the tropical Atlantic, notably a negative phase of the Atlantic Meridional Mode (AMM) in 2015 and 2018, and a positive phase of the Atlantic Niño in 2018. Negative AMM in these 2 years is also associated with stronger trade winds and enhanced northwest Africa upwelling, probably resulting in stronger southwestward nutrient transport into the eastern part of CWA. Moreover, in contrast with most years, important secondary winter blooms took place in both 2015 and 2018 in the northern part of CWA, associated with excessive wind-driven equatorial upwelling and anomalously strong northwestward nutrient transport.

VL - 72 TI - Physical drivers of pelagic sargassum bloom interannual variability in the Central West Atlantic over 2010?2020 AV - public EP - 404 N1 - Funding Information: This publication is supported by the UK Economic and Social Research Council through the Global Challenges Research Fund (GCRF) project, Teleconnected sargassum risks across the Atlantic: building capacity for TRansformational Adaptation in the Caribbean and West Africa (SARTRAC), grant number ES/T002964/1. We acknowledge the Optical Oceanography Laboratory at the University of South Florida, for freely providing AFAI images via https://optics.marine.usf.edu . Funding Information: This publication is supported by the UK Economic and Social Research Council through the Global Challenges Research Fund (GCRF) project, Teleconnected sargassum risks across the Atlantic: building capacity for TRansformational Adaptation in the Caribbean and West Africa (SARTRAC) , grant number ES/T002964/1. We acknowledge the Optical Oceanography Laboratory at the University of South Florida, for freely providing AFAI images via https://optics.marine.usf.edu. Funding Information: The research was funded by the UK?s Economic and Social Research Council through the Global Challenges Research Fund (GCRF) project, Teleconnected sargassum risks across the Atlantic: building capacity for TRansformational Adaptation in the Caribbean and West Africa (SARTRAC), grant number ES/T002964/1. Publisher Copyright: © 2022, The Author(s). Y1 - 2022/06// JF - Ocean Dynamics KW - Climatic modes KW - Ocean circulation KW - Sargassum KW - Trade winds KW - Tropical North Atlantic SN - 1616-7341 SP - 383 ER - TY - JOUR ID - soton440806 UR - https://eprints.soton.ac.uk/440806/ IS - 11-12 A1 - Skliris, Nikolaos A1 - Marsh, Robert A1 - Mecking, Jennifer A1 - Zika, Jan D N2 - Observations over the last 40 years show that the Atlantic Ocean salinity pattern has amplified, likely in response to changes in the atmospheric branch of the global water cycle. Observational estimates of oceanic meridional freshwater transport (FWT) at 26.5° N indicate a large increase over the last few decades, during an apparent decrease in the Atlantic Meridional Overturning Circulation (AMOC). However, there is limited observation based information at other latitudes. The relative importance of changing FWT divergence in these trends remains uncertain. Ten models from the Coupled Model Intercomparison Project Phase 5 are analysed for AMOC, FWT, water cycle, and salinity changes over 1950?2100. Over this timescale, strong trends in the water cycle and oceanic freshwater transports emerge, a part of anthropogenic climate change. Results show that as the water cycle amplifies with warming, FWT strengthens (more southward freshwater transport) throughout the Atlantic sector over the 21st century. FWT strengthens in the North Atlantic subtropical region in spite of declining AMOC, as the long-term trend is dominated by salinity change. The AMOC decline also induces a southward shift of the Inter-Tropical Convergence Zone and a dipole pattern of precipitation change over the tropical region. The consequent decrease in freshwater input north of the equator together with increasing net evaporation lead to strong salinification of the North Atlantic sub-tropical region, enhancing net northward salt transport. This opposes the influence of further AMOC weakening and results in intensifying southward freshwater transports across the entire Atlantic. VL - 54 TI - Changing water cycle and freshwater transports in the Atlantic Ocean in observations and CMIP5 models AV - public EP - 4989 N1 - Funding Information: This work is part of the UK Natural Environment Research Council funded project CLimate scale analysis of Air and Water masses (CLAW). We acknowledge the World Climate Research Program?s Working Group on Coupled Modeling, which is responsible for CMIP5, and we thank the climate modelling groups for producing and making available their model output. We acknowledge the Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory, for making available the freshwater flux datasets. Publisher Copyright: © 2020, The Author(s). Y1 - 2020/06/01/ JF - Climate Dynamics KW - Ocean freshwater transports · Freshwater budget · Water cycle · Salinity · Atlantic Ocean SN - 0930-7575 SP - 4971 ER - TY - JOUR ID - soton365212 UR - https://eprints.soton.ac.uk/365212/ IS - 2 A1 - Skliris, Nikolaos A1 - Sofianos, Sarantis S. A1 - Gkanasos, Athanasios A1 - Axaopoulos, Panagiotis A1 - Mantziafou, Anneta A1 - Vervatis, Vassilis Y1 - 2011/11// N2 - The inter-annual/decadal scale variability of the Aegean Sea Surface Temperature (SST) is investigated by means of long-term series of satellite-derived and in situ data. Monthly mean declouded SST maps are constructed over the 1985?2008 period, based on a re-analysis of AVHRR Oceans Pathfinder optimally interpolated data over the Aegean Sea. Basin-average SST time series are also constructed using the ICOADS in situ data over 1950?2006. Results indicate a small SST decreasing trend until the early nineties, and then a rapid surface warming consistent with the acceleration of the SST rise observed on the global ocean scale. Decadal-scale SST anomalies were found to be negatively correlated with the winter North Atlantic Oscillation (NAO) index over the last 60 years suggesting that along with global warming effects on the regional scale, a part of the long-term SST variability in the Aegean Sea is driven by large scale atmospheric natural variability patterns. In particular, the acceleration of surface warming in the Aegean Sea began nearly simultaneously with the NAO index abrupt shift in the mid-nineties from strongly positive values to weakly positive/negative values. JF - Advances in Oceanography and Limnology VL - 2 KW - Aegean Sea KW - sea surface temperature KW - AVHRR KW - ICOADS KW - North Atlantic Oscillation KW - Indian Monsoon SN - 1947-5721 TI - Long-term sea surface temperature variability in the Aegean Sea SP - 125 AV - public EP - 139 ER - TY - RPRT ID - soton157097 UR - https://eprints.soton.ac.uk/157097/ A1 - Smeed, D.A. Y1 - 2009/// N2 - This report describes the trial glider operations conducted as part of the RAPID-MOC project
conducted between 15 September ? 24 November 2008 and 21 May ? 21 July 2009 between
the Canary Islands and the coast of Morocco.
The RAPID-MOC mooring array at 26.5°N is designed to quantify the strength and variability
of the transport of mass and heat associated with the Atlantic meridional overturning
circulation (MOC). Currently the majority of the measurements are made from moored
instruments.
The objective of this study was to assess the contribution that autonomous gliders could make
to the monitoring array. In particular the focus was on the use of gliders on the shallow eastern
boundary of the North Atlantic. This is the part of the RAPID array that has suffered the
greatest loss of instruments, in large part due to suspected fishing activity on the continental
slope. Furthermore, initial results (Chidichimo 2009) from the first three years of the RAPID
array have shown that the largest contribution to the seasonal variation in the MOC is the
variability of density on the eastern boundary in the upper 1000m.
It is expected that gliders will be less susceptible to loss by fishing than the moored
instruments. Another advantage of gliders is that data are retrieved in real-time via Iridium
satellite communications, further reducing the risk of data loss.
http://www.noc.soton.soton.ac.uk/rapidmoc
and/or
http://www.noc.soton.ac.uk/omf/projects/glider
PB - National Oceanography Centre T3 - 44 KW - 26.5°N KW - MOC KW - Atlantic Ocean KW - Eastern Boundary KW - glider KW - meridional overturning circulation KW - MicroCAT KW - mooring array KW - North Atlantic KW - RAPID KW - RAPIDMOC KW - RAPID-WATCH KW - THC KW - thermohaline circulation ED - Wright, P.G. M1 - project_report TI - Glider Cruise Report No. 1. Bellamite and Dynamite, 15 Sep-24 Nov 2008 and 21 May-21 Jul 2009: RAPID glider deployment report AV - public EP - 107 ER - TY - JOUR ID - soton340765 UR - https://eprints.soton.ac.uk/340765/ IS - 23 A1 - Smith, H.E.K. A1 - Tyrrell, T. A1 - Charalampopoulou, A. A1 - Dumousseaud, C. A1 - Legge, O.J. A1 - Birchenough, S. A1 - Pettit, LR. A1 - Garley, R. A1 - Hartman, S.E. A1 - Hartman, M.C. A1 - Sagoo, N. A1 - Daniels, C.J. A1 - Achterberg, E.P. A1 - Hydes, D.J. Y1 - 2012/05/21/ N2 - calcifiers, their possible susceptibility to ocean acidification is of major concern. Laboratory studies at enhanced pCO2 levels have produced divergent results without overall consensus. However, it has been predicted from these studies that, although calcification may not be depressed in all species, acidification will produce ?a transition in dominance from more to less heavily calcified coccolithophores? [Ridgwell A, et al., (2009) Biogeosciences 6:2611?2623]. A recent observational study [Beaufort L, et al., (2011) Nature 476:80?83] also suggested that coccolithophores are less calcified in more acidic conditions. We present the results of a large observational study of coccolithophore morphology in the Bay of Biscay. Samples were collected once a month for over a year, along a 1,000-km-long transect. Our data clearly show that there is a pronounced seasonality in the morphotypes of Emiliania huxleyi, the most abundant coccolithophore species. Whereas pH and CaCO3 saturation are lowest in winter, the E. huxleyi population shifts from <10% (summer) to >90% (winter) of the heavily calcified form. However, it is unlikely that the shifts in carbonate chemistry alone caused the morphotype shift. Our finding that the most heavily calcified morphotype dominates when conditions are most acidic is contrary to the earlier predictions and raises further questions about the fate of coccolithophores in a high-CO2 world. JF - Proceedings of the National Academy of Sciences VL - 109 KW - phytoplankton KW - north atlantic KW - climate change SN - 0027-8424 TI - Predominance of heavily calcified coccolithophores at low CaCO3 saturation during winter in the Bay of Biscay SP - 8845 AV - none EP - 8849 ER - TY - JOUR ID - soton66330 UR - https://eprints.soton.ac.uk/66330/ IS - 4-5 A1 - Smith, I. Philip A1 - Booker, Douglas J. A1 - Wells, Neil C. Y1 - 2009/05// N2 - A bioenergetic model of marine phase, wild Atlantic salmon was constructed to investigate the potential effects on post-smolt growth of predicted changes in oceanic conditions. Short-term estimates of growth in weight were similar to measurements in captivity and simulated growth varied with water temperature and swimming speed as expected. Longer-term estimates of growth in length were less than that achieved by wild salmon, particularly with constant swimming assumed. The model was sensitive to parameters relating to maximum daily food consumption, respiration and the relationships between body energy content, length and weight. Some of the sensitive parameters were based on substantive information on Atlantic salmon and their realistic ranges are likely to be much narrower than those tested. However, other parameter values were based on scant data, farmed Atlantic salmon or other salmonid species, and are therefore less certain and indicate where future empirical research should be focussed.

JF - Marine Environmental Research VL - 67 KW - Atlantic salmon KW - Post-smolt KW - Marine phase KW - Growth KW - Temperature KW - Climate change KW - Marine ecology KW - Mathematical models SN - 0141-1136 TI - Bioenergetic modelling of the marine phase of Atlantic salmon (Salmo salar L.) SP - 246 AV - none EP - 258 ER - TY - RPRT ID - soton299 UR - https://eprints.soton.ac.uk/299/ A1 - Smythe-Wright, D. Y1 - 1999/// N2 - RRS Discovery Cruise 233, CHAOS (Chemical and Hydrographic Atlantic Ocean Survey) combined a long meridional section notionally along 20°W from 20°N to Iceland with a detailed survey of the Rockall Trough. The meridional section was designed to i) establish the sources and sinks of halocarbons in subtropical and subpolar waters during spring bloom conditions; ii) to examine the decadal scale variability in the eastern Atlantic over the last 40 years by repeating the northern part of the WOCE A16 line first occupied in 1988 and again in 1993 (NATL 93), and parts of other sections occupied in 1957, 1973, 1983 and 1991; iii). to study the spreading, mixing and ventilation rates of Labrador Sea Water, Mediterranean Water, and waters of Southern Ocean origin (Antarctic Intermediate Water and Antarctic Bottom Water) which extend into the northeast Atlantic. The detailed survey of the Rockall Trough comprised 4 zonal sections notionally at 57°N, 56°N, 54°N and 52°N in order to i) make a detailed study of the water masses in the Rockall Trough with particular emphasis on their circulation/recirculation patterns ii) to re-occupy stations along the Ellett line (57°N) to continue the time series dating from 1975. The sections were completed with CTD, LADCP, tracer chemistry (CFCs, nutrients, oxygen), alkalinity and pH measurements to full depth and a suite of halocarbon measurements together with sampling for plant pigments and biological species to 200m. Continuous measurements of atmospheric halocarbons, pCO2, meteorological measurements, VM -ADCP, depth, TSG, radiometer SST and navigation data were also made. All measurements were made to WOCE standards and the final data submitted to the WOCE programme. PB - Southampton Oceanography Centre, University of Southampton T3 - 24 KW - ADCP KW - alkalinity KW - ATLNE KW - atmospheric halocarbons KW - biology KW - CFC KW - CHAOS KW - CO2 KW - cruise 233 1998 KW - Discovery KW - halocarbons KW - Iceland Waters KW - LADCP KW - meteorological data KW - meteorological measurements KW - Northeast Atlantic KW - nutrients KW - oxygen KW - pH KW - plant pigments KW - Rockall Trough KW - SISTeR KW - tracer chemistry KW - tracers KW - WOCE M1 - project_report TI - RRS Discovery Cruise 233, 23 Apr-01 Jun 1998. A Chemical and Hydrographic Atlantic Ocean Survey: CHAOS AV - public EP - 86 ER - TY - JOUR ID - soton72499 UR - https://eprints.soton.ac.uk/72499/ IS - 15 A1 - Smythe-Wright, Denise A1 - Boswell, Stephen A1 - Kim, Young-Nam A1 - Kemp, Alan Y1 - 2010/08/01/ N2 - We have made a comprehensive study of pigment distributions and microscopically determined phytoplankton abundances within the Porcupine Abyssal Plain (PAP) location in the North Atlantic to better understand phytoplankton variability, and make some suggestions regarding the composition of the material falling to the sea bed and its impacts on benthic organisms such as Amperima rosea. The area has been the focus of many studies of ocean fluxes and benthic communities over recent years, but little attention has been given to the spatio-temporal variability in the surface waters. Dawn casts over a 12-day period at the PAP mooring site (48.83°N 16.5°W) revealed the presence of only one species, the diatom Actinocyclus exiguus, at bloom concentrations for just 5 days. Smaller populations of other diatoms and the dinoflagellates Gymnodinium and Gyrodinium were also present at this time. Following this 5-day interval, a mixed population of small?sized dinoflagellates, prymnesiophytes, prasinophytes, chrysophytes and cyanobacteria occurred. It is clear from concomitant CTD/bottle surveys that rapid changes in phytoplankton community structure at a fixed time series position do not necessarily reflect a degradation or manifestation of one particular species but rather represent the movement of eddies and other water masses within very short timescales. These cause substantial variability in the species class and size fraction that may explain the variability in carbon export that has been seen at the PAP site. We also make some suggestions on the variable composition of the material falling to the seabed and its impact on benthic organisms such as Amperima rosea. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 57 KW - Pigments KW - Phytoplankton KW - Variability. North Atlantic KW - Porcupine Abyssal Plain KW - 48.83°N 16.5°W SN - 0967-0645 TI - Spatio-temporal changes in the distribution of phytopigments and phytoplanktonic groups at the Porcupine Abyssal Plain (PAP) site SP - 1324 AV - none EP - 1335 ER - TY - JOUR ID - soton434368 UR - https://eprints.soton.ac.uk/434368/ A1 - Sousa, Ricardo A1 - Henriques, Paulo A1 - Vasconcelos, Joana A1 - Faria, Graca A1 - Riera, Rodrigo A1 - Pinto, Ana Rita A1 - Delgado, Joaõ A1 - Hawkins, Stephen J. Y1 - 2019/06/18/ N2 -

Hermaphroditism is thought to be an advantageous strategy common in marine molluscs that exhibit simultaneous, sequential or alternating hermaphroditism. Several species of patellid limpets have previously been shown to be protandrous hermaphrodites. The present study aimed to confirm whether this phenomenon occurs in Patella piperata. Transitional forms of simultaneous protandrous hermaphroditism were found in intermediate size classes of P. piperata, in Madeira (North-eastern Atlantic). Sequential hermaphroditism was confirmed after histological analysis. The overall sex-ratio was biased towards females but approached similar proportions in the larger size classes. Analysis of size at sex change showed that at a shell length of 36 mm 50% of the population probably have changed sex. The results reported confirm the occurrence of sequential hermaphroditism. These findings are of utmost importance to the understanding of the reproductive biology of this species with direct effect on management and conservation of this traditionally harvested limpet.

JF - Journal of the Marine Biological Association of the United Kingdom KW - Atlantic Ocean KW - intertidal KW - Madeira KW - Mollusca KW - Patellogastropoda KW - sex change SN - 0025-3154 TI - First observations of hermaphroditism in the patellid limpet Patella piperata Gould, 1846 AV - none ER - TY - JOUR ID - soton337002 UR - https://eprints.soton.ac.uk/337002/ A1 - Spencer, Matthew A1 - Mieszkowska, Nova A1 - Robinson, Leonie A. A1 - Simpson, Stephen D. A1 - Burrows, Micheal T. A1 - Birchenough, Silvana N. A1 - Capasso, Eva A1 - Cleall-Harding, Polly A1 - Crummy, Julia A1 - Duck, Callan A1 - Eloire, Damien A1 - Frost, Matthew A1 - Hall, Ailsa J. A1 - Hawkins, Stephen J. A1 - Johns, David G. A1 - Sims, David W. A1 - Smyth, Timothy J. A1 - Frid, Chris L.J. Y1 - 2012/// N2 - Regime shifts are sudden changes in ecosystem structure that can be detected across several ecosystem components.
The concept that regime shifts are common in marine ecosystems has gained popularity in recent years. Many studies have searched for the step-like changes in ecosystem state expected under a simple interpretation of this idea. However, other kinds of change, such as pervasive trends, have often been ignored. We assembled over 300 ecological time series from seven UK marine regions, covering two to three decades. We developed state-space models for the
first principal component of the time series in each region, a common measure of ecosystem state. Our models
allowed both trends and step changes, possibly in combination. We found trends in three of seven regions and step changes in two of seven regions. Gradual and sudden changes are therefore important trajectories to consider in marine ecosystems. JF - Global Change Biology VL - 18 KW - benthos KW - fish KW - NE Atlantic KW - North Sea KW - phytoplankton KW - regime shifts KW - rocky shores KW - seals KW - state-space model KW - time series KW - zooplankton SN - 1354-1013 TI - Region-wide changes in marine ecosystem dynamics: state-space models to distinguish trends from step changes SP - 1270 AV - restricted EP - 1281 ER - TY - JOUR ID - soton249 UR - http://www.pubs.royalsoc.ac.uk/phil_trans_phys_homepage.shtml A1 - Srokosz, M.A. Y1 - 2003/// N2 - In this paper the scientific challenges of observing, modelling, understanding and predicting rapid changes in climate are discussed, with a specific focus on the role of the Atlantic thermohaline circulation. The palaeo and present-day observational and modelling studies being carried out to meet these challenges, under the aegis of a new NERC Rapid Climate Change thematic programme (RAPID), are outlined.
In particular, the paper describes the work being done to monitor changes in the meridional overturning circulation of the North Atlantic. The paper concludes with some speculative comments about potential mechanisms for rapid changes. JF - Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences VL - 361 KW - rapid climate change KW - thermohaline circulation KW - palaeo KW - modelling KW - observations KW - Atlantic SN - 1364-503X TI - Rapid climate change: scientific challenges and the new NERC programme SP - 2061 AV - public EP - 2078 ER - TY - JOUR ID - soton6094 UR - https://eprints.soton.ac.uk/6094/ IS - 3-4 A1 - Srokosz, M.A. Y1 - 2002/// JF - CLIVAR Exchanges VL - 7 KW - THERMOHALINE CIRCULATION KW - CLIMATE CHANGE KW - CLIMATIC CHANGES KW - RAPID KW - ATLANTIC OCEAN KW - METEOROLOGY TI - Rapid Climate Change (RAPID) - a new UK Natural Environmental Research Council (NERC) programme SP - 66 AV - none EP - 68 ER - TY - RPRT ID - soton309 UR - https://eprints.soton.ac.uk/309/ A1 - Srokosz, M.A. Y1 - 1997/// N2 - This report describes RRS Discovery Cruise No. 227, which was carried out to measure plankton patchiness in the eastern North Atlantic (in the area of 16-20?W, 47-49?N), during the period 15 April to 16 May 1997 (the time of the spring bloom). Meteorological, physical, optical, chemical and biological measurements were made using a combination of underway sampling (MultiMet, ADCP, TSG, fluorimeter, nutrients), towed instrumentation (SeaSoar, OPC, Lightfish, LHPR) and on station sampling (CTD, nitrate sensor, water bottles, Satlantic light sensors, vertical nets). Two large scale surveys, and three small scale surveys were carried out during the cruise. Patchiness in both the phytoplankton (measured by the SeaSoar fluorimeter) and the zooplankton (measured by the OPC) distributions was observed. Satellite SST data (from AVHRR) were received in near real time during the cruise, which aided the interpretation of the ship-based observations. Data acquired during the cruise were assimilated into a coupled bio-physical model, which was run on the ship, in an attempt to provide near real time forecasts of the ocean biology and physics in the survey area. PB - Southampton Oceanography Centre, University of Southampton T3 - 12 KW - ADCP KW - algal bloom KW - AVHRR KW - bio-optics KW - biological-physical interactions KW - cruise 227 1997 KW - CTD KW - currents KW - data assimilation KW - Discovery KW - eastern North Atlantic KW - infra-red imagery KW - meteorology KW - near real time modelling KW - nitrate sensor KW - nutrients KW - ocean colour KW - OPC KW - plankton patchiness KW - satellite altimetry KW - satellite data KW - SEASOAR KW - surface temperature KW - vertical nets M1 - project_report TI - RRS Discovery Cruise 227, 15 Apr-16 May 1997. Plankton patchiness studies by ship and satellite: P2S3 AV - public EP - 76 ER - TY - JOUR ID - soton2132 UR - https://eprints.soton.ac.uk/2132/ IS - 4 A1 - Srokosz, M.A. A1 - Martin, A.P. A1 - Fasham, M.J.R. Y1 - 2003/// N2 - In situations where the direct physical forcing of biological processes, through nutrient supply or light limitation of phytoplankton, does not show significant spatial variability, it is demonstrated that the effects of the mesoscale circulation and population dynamics on plankton patchiness are in principle, separable. In this case, the physical stirring and mixing control the size and shape of structures seen in plankton distributions, whilst the biological dynamics controls the size of the populations within those structures. This is demonstrated using field observations and a simple process model. The field data, which come from mesoscale surveys of a region (16 -20W, 46 - 49N) in the eastern North Atlantic during April-May 1997, provide simultaneous continuous measurements of hydrography, phytoplankton and three size classes of zooplankton with the same spatiotemporal resolution and sampling. The lack of significant spatial variability in the physical forcing arises due to the absence of any strong frontal features in the area and to the fact that storm mixing maintained nutrient levels above limiting values throughout the surveys. When the observed biological parameters are plotted in phase space, a close relationship between constituents of the ecosystem is revealed that is missed by other data analysis techniques. In particular, this approach provides an explanation of how zooplankton and phytoplankton can be simultaneously positively and negatively correlated at different sites in a region and yet still tightly coupled. It is further demonstrated that the much-maligned standard feature of surveying plankton patchiness at the mesoscale - asynopticity in sampling - actually assists in the extraction of the phase space relationships. JF - Journal of Marine Research VL - 61 KW - PLANKTON KW - PATCHINESS KW - NORTH ATLANTIC OCEAN KW - ATLN KW - NUTRIENTS KW - LIGHT KW - MESOSCALE FEATURES KW - "DISCOVERY" KW - ECOSYSTEM MODELLING KW - BIOLOGY KW - GEOLOGY SN - 0022-2402 TI - On the role of biological dynamics in plankton patchiness at the mesoscale: an example from the eastern North Atlantic Ocean SP - 517 AV - none EP - 537 ER - TY - JOUR ID - soton189541 UR - https://eprints.soton.ac.uk/189541/ A1 - Stanford, J.D. A1 - Rohling, E.J. A1 - Bacon, S. A1 - Holliday, N.P. Y1 - 2011/11/07/ N2 - The global Thermohaline Circulation (THC) is primarily driven by the cooling and sinking of northward flowing North Atlantic surface waters in the Nordic Seas to form North Atlantic Deep Water (NADW) that flows southward as a component of the Deep Western Boundary Current (DWBC). It is widely accepted that major freshwater injections have disrupted the formation of NADW in the past, causing widespread cooling over the North Atlantic. Eirik Drift, a contourite south of Greenland, was formed from deposition of sediments carried in the DWBC, so contains information about DWBC variability. Before now, the spatial and temporal variability of the surface and deep water currents, and their relationship with the associated sedimentation have not been fully understood. Here, we present a review of the key findings from the RAPID Cape Farewell project at Eirik Drift, a multi-disciplinary study which included hydrographic profiles, sub-bottom and sea-floor geophysical data, and multi-proxy analyses of a marine sediment core. We use these previously published results to further elucidate the oceanographic processes above Eirik Drift and relate these results to the sedimentation patterns. We also resolve, using a down-core record of NADW flow intensity, how bottom currents in this region changed in association with freshwater forcing during the last deglaciation. JF - Global and Planetary Change VL - 79 KW - Thermohaline Circulation KW - Eirik Drift KW - Deep Western Boundary Current KW - North Atlantic Deep Water SN - 0921-8181 TI - A review of the deep and surface currents around Eirik Drift, south of Greenland: Comparison of the past with the present SP - 244 AV - none EP - 254 ER - TY - JOUR ID - soton188311 UR - https://eprints.soton.ac.uk/188311/ IS - 9-10 A1 - Stanford, J.D. A1 - Rohling, E.J. A1 - Bacon, S. A1 - Roberts, A.P. A1 - Grousset, F.E. A1 - Bolshaw, M. Y1 - 2011/05// N2 - New records of planktonic foraminiferal ?18O and lithic and foraminiferal counts from Eirik Drift are combined with published data from the Nordic Seas and the ?Ice Rafted Debris (IRD) belt?, to portray a sequence of events through Heinrich event 1 (H1). These events progressed from an onset of meltwater release at not, vert, similar19 ka BP, through the ?conventional? H1 IRD deposition phase in the IRD belt starting from not, vert, similar17.5 ka BP, to a final phase between 16.5 and not, vert, similar15 ka BP that was characterised by a pooling of freshwater in the Nordic Seas, which we suggest was hyperpycnally injected into that basin. After not, vert, similar15 ka BP, this freshwater was purged from the Nordic Seas into the North Atlantic, which preconditioned the Nordic Seas for convective deep-water formation. This allowed an abrupt re-start of North Atlantic Deep Water (NADW) formation in the Nordic Seas at the Bølling warming (14.6 ka BP). In contrast to previous estimates for the duration of H1 (i.e., 1000 years to only a century or two), the total, combined composite H1 signal presented here had a duration of over 4000 yrs (not, vert, similar19?14.6 ka BP), which spanned the entire period of NADW collapse. It appears that deep-water formation and climate are not simply controlled by the magnitude or rate of meltwater addition. Instead the location of meltwater injections may be more important, with NADW formation being particularly sensitive to surface freshening in the Arctic/Nordic Seas. JF - Quaternary Science Reviews VL - 30 KW - Heinrich event 1 KW - North Atlantic deep water formation KW - Nordic seas SN - 0277-3791 TI - A new concept for the paleoceanographic evolution of Heinrich event 1 in the North Atlantic SP - 1047 AV - restricted EP - 1066 ER - TY - JOUR ID - soton6021 UR - https://eprints.soton.ac.uk/6021/ IS - 3 A1 - Steinke, M. A1 - Malin, G. A1 - Archer, S.D. A1 - Burkill, P.H. A1 - Liss, P.S. Y1 - 2002/// JF - Aquatic Microbial Ecology VL - 26 KW - DMSP lyase · Dimethyl sulphide · DMS · Dinoflagellates · Coccolithophorids · Emiliania huxleyi · North Atlantic SN - 0948-3055 TI - DMS production in a coccolithophorid bloom: evidence for the importance of dinoflagellate DMSP lyases SP - 259 AV - none EP - 270 ER - TY - JOUR N1 - Funding Information: We thank reviewer Dr. Peter Bijl, the anonymous reviewer, and editor Dr. Laura Robinson, for their very thorough and constructive comments. Prof. Emeritus Claus Heilmann-Clausen, Dr. Joost Frieling is sincerely thanked for good and helpful discussions. P. Sargent Bray, Bo Schultz, Dr. Sverre Planke, Prof. Christian Tegner, and Dr. Valentin Zuchuat are all warmly thanked for their assistance. This project was supported by the Research Council of Norway 's funding schemes ?Unge Forskertallenter? project number 263000 (project Ashlantic) and ?Centres of Excellence? project number 223272 , and their funding to the Norwegian Research School DEEP with project number 249040/F60 . J. Whiteside is thankful to support from an Annual Adventures in Research grant. J. Tierney acknowledges support from The David and Lucile Packard Foundation and The Heising-Simons Foundation Grant # 2016-015 . Publisher Copyright: © 2020 The Author(s) ID - soton442849 UR - https://eprints.soton.ac.uk/442849/ A1 - Stokke, Ella W. A1 - Jones, Morgan T. A1 - Tierney, Jessica E. A1 - Svensen, Henrik H. A1 - Whiteside, Jessica H. Y1 - 2020/08/15/ N2 -

The Paleocene-Eocene Thermal Maximum (PETM; ?55.9 Ma) was a hyperthermal event associated with large carbon cycle perturbations, sustained global warming, and marine and terrestrial environmental changes. One possible trigger and/or source of the carbon release that initiated the PETM is the emplacement of the North Atlantic Igneous Province (NAIP). This study focuses on an expanded section of marine clays and diatomite on Fur Island in northern Denmark, where the entire PETM sequence has been identified by a negative ?4.5? ? 13C TOC excursion. This remarkably well-preserved section also contains >180 interbedded ash layers sourced from the NAIP, making it an ideal site for investigating the correlations between large-scale volcanism and environmental changes. This study provides a new and complete high-resolution TEX 86-derived sea-surface temperature (SST) reconstruction over the entire PETM and the post-PETM section (up to about 54.6 Ma). The palaeothermometry record indicates an apparent short-lived cooling episode in the late Paleocene, followed by a pronounced temperature response to the PETM carbon cycle perturbations with a ?10 °C SST increase during the PETM onset (up to ?33 °C). Extreme SSTs fall shortly after the PETM onset, and continue to decrease during the PETM body and recovery, down to anomalously cool SSTs post-PETM (?11?23 °C). Both phases of potential cooling coincide with proxies of active NAIP volcanism, suggesting a causal connection, although several overprinting non-thermal factors complicate interpretations of the TEX 86 values. Indices of effusive and explosive NAIP volcanism are largely absent from the Danish stratigraphy during the PETM body, though a re-emergence toward the end of the PETM suggest NAIP volcanism might have played a role in the PETM termination in the North Sea. This new SST record completes the previous fragmented view of climate changes at this globally important PETM site, and indicates large temperature variations in the North Sea during the earliest Eocene that are possibly linked to NAIP volcanism.

JF - Earth and Planetary Science Letters VL - 544 KW - North Atlantic Igneous Province KW - PETM KW - TEX KW - palaeotemperatures SN - 0012-821X TI - Temperature changes across the Paleocene-Eocene Thermal Maximum ? a new high-resolution TEX86 temperature record from the Eastern North Sea Basin AV - public ER - TY - JOUR ID - soton382053 UR - https://eprints.soton.ac.uk/382053/ A1 - Sévellec, Florian A1 - Fedorov, Alexey V. Y1 - 2015/11/01/ N2 - A striking feature of paleoclimate records is the greater stability of the Holocene epoch relative to the preceding glacial interval, especially apparent in the North Atlantic region. In particular, strong irregular variability with an approximately 1500 yr period, known as the Dansgaard?Oeschger (D?O) events, punctuates the last glaciation, but is absent during the interglacial. Prevailing theories, modeling and data suggest that these events, seen as abrupt warming episodes in Greenland ice cores and sea surface temperature records in the North Atlantic, are linked to reorganizations of the Atlantic Meridional Overturning Circulation (AMOC). In this study, using a new low-order ocean model that reproduces a realistic power spectrum of millennial variability, we explore differences in the AMOC stability between glacial and interglacial intervals of the 100 kyr glacial cycle of the Late Pleistocene (1 kyr=1000 yr1 kyr=1000 yr). Previous modeling studies show that the edge of sea ice in the North Atlantic shifts southward during glacial intervals, moving the region of the North Atlantic Deep Water formation and the AMOC also southward. Here we demonstrate that, by shifting the AMOC with respect to the mean atmospheric precipitation field, such a displacement makes the system unstable, which explains chaotic millennial variability during the glacials and the persistence of stable ocean conditions during the interglacials. JF - Earth and Planetary Science Letters VL - 429 KW - Atlantic meridional overturning circulation KW - Holocene climate stability KW - Dansgaard?Oeschger events KW - millennial climate variability KW - glacial?interglacial cycle SN - 0012-821X TI - Unstable AMOC during glacial intervals and millennial variability: The role of mean sea ice extent SP - 60 AV - public EP - 68 ER - TY - JOUR ID - soton365632 UR - https://eprints.soton.ac.uk/365632/ IS - 10 A1 - Sévellec, Florian A1 - Fedorov, Alexey V. Y1 - 2014/05// N2 - A salient feature of paleorecords of the last glacial interval in the North Atlantic is pronounced millennial variability, commonly known as Dansgaard?Oeschger events. It is believed that these events are related to variations in the Atlantic meridional overturning circulation and heat transport. Here, the authors formulate a new low-order model, based on the Howard?Malkus loop representation of ocean circulation, capable of reproducing millennial variability and its chaotic dynamics realistically. It is shown that even in this chaotic model changes in the state of the meridional overturning circulation are predictable. Accordingly, the authors define two predictive indices which give accurate predictions for the time the circulation should remain in the on phase and then stay in the subsequent off phase. These indices depend mainly on ocean stratification and describe the linear growth of small perturbations in the system. Thus, monitoring particular indices of the ocean state could help predict a potential shutdown of the overturning circulation. JF - Journal of Climate VL - 27 KW - North Atlantic Ocean KW - Meridional overturning circulation KW - Climate prediction KW - Nonlinear models KW - Climate variability SN - 0894-8755 TI - Millennial Variability in an Idealized Ocean Model: Predicting the AMOC Regime Shifts SP - 3551 AV - public EP - 3564 ER - TY - JOUR ID - soton378804 UR - https://eprints.soton.ac.uk/378804/ IS - 9 A1 - Sévellec, Florian A1 - Huck, Thierry Y1 - 2015/09// N2 - A weakly damped mode of variability, corresponding to the oceanic signature of the Atlantic Multidecadal Oscillation (AMO), was found through the linear stability analysis of a realistic ocean General Circulation Model. A simple 2-level model was proposed to rationalize both its period and damping rate. This model is extended here to 3-level to investigate how the mode can draw energy from the mean flow, as found in various ocean and coupled models. A linear stability analysis in this 3-level model shows that the positive growth rate of the oscillatory mode depends on the zonally-averaged isopycnal slope. This mode corresponds to a westward propagation of density anomalies in the pycnocline, typical of large-scale baroclinic Rossby waves. The most unstable mode corresponds to the largest scale one (at least for low isopycnal slope). The mode can be described in four phases composing a full oscillation cycle: (1) basin-scale warming of the North Atlantic (AMO positive phase), (2) decrease in upper ocean poleward transport (hence a reduction of the Atlantic Meridional Overturning Circulation, AMOC), (3) basin-scale cooling (negative AMO), (4) AMOC intensification. A criterion is developed to test, in oceanic datasets or numerical models, whether this multidecadal oscillation is an unstable oceanic internal mode of variability, or is stable and externally forced. Consistently with classical theory of baroclinic instability, this criterion depends on the vertical structure of the mode. If the upper pycnocline signature is in advance of the deeper pycnocline signature with respect to the westward propagation, the mode is unstable and could be described as an oceanic internal mode of variability. JF - Journal of Physical Oceanography VL - 45 KW - Geographic location/entity KW - North Atlantic Ocean KW - Circulation/ Dynamics KW - Dynamics KW - Meridional overturning circulation KW - Atm/Ocean Structure/ Phenomena KW - Thermohaline circulation KW - Physical Meteorology and Climatology KW - Climate variability KW - Variability KW - Multidecadal variability SN - 0022-3670 TI - Theoretical investigation of the Atlantic Multidecadal Oscillation SP - 2189 AV - public EP - 2208 ER - TY - JOUR ID - soton41937 UR - https://eprints.soton.ac.uk/41937/ IS - 14-16 A1 - Tarran, G.A. A1 - Heywood, J.L. A1 - Zubkov, M.V. Y1 - 2006/// N2 - The latitudinal distributions of picoeukaryote phytoplankton (PEUK), coccolithophores (COCCO), cryptophytes (CRYPTO) and other nanoeukaryote phytoplankton (NEUK) were studied in the Atlantic Ocean between 49°N and 46°S in September?October 2003 and April?June 2004 by flow cytometry. Phytoplankton abundance and carbon (C) biomass varied considerably with latitude and down through the water column. Abundance and C biomass of all eukaryotic groups studied were highest in North and South Atlantic temperate waters and in the Mauritanian Upwelling off the west coast of Africa, where the total C biomass of eukaryotic phytoplankton smaller than 10 ?m reached almost 150 mg C m?3. Phytoplankton in the Equatorial Upwelling region was concentrated well below the surface at 50?80 m, with total C biomass in this layer being approximately 4 times that in the mixed layer. The North and South Atlantic Gyres supported much lower eukaryotic phytoplankton C biomass, with total eukaryote C biomass only reaching 2?3 mg C m?3, peaking below 100 m. Of the four eukaryote groups studied, the PEUK were the most abundant, reaching densities of up to 40,000 cells cm?3. They often contributed between 25% and 60% of total C biomass, particularly in the deep chlorophyll maxima of the different oceanic regions and also in the South Atlantic temperate waters, both in austral spring and autumn. NEUK also contributed significantly to C biomass. They generally dominated in the mixed layer, where they contributed 65?85% of total C biomass in the subtropical gyres and in North Atlantic temperate waters. CRYPTO and COCCO were generally less abundant. CRYPTO attained highest abundance in the Southern Temperate waters of over 500 cells cm?3 on both cruises. COCCO were often undetectable but on the European continental shelf abundance reached up to 2600 cells cm?3 during AMT 14. The C biomass standing stock of eukaryotic phytoplankton (<10 ?m) for the Atlantic Ocean as a whole was estimated to be 80 million tonnes C during AMT 13, approximately one-third of total phytoplankton C biomass in the Atlantic Ocean. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 53 KW - Atlantic Ocean KW - Atlantic Meridional Transect KW - fflow cytometry KW - nanoplankton KW - picoplankton KW - community composition SN - 0967-0645 TI - Latitudinal changes in the standing stocks of nano- and picophytoplankton in the Atlantic Ocean SP - 1516 AV - none EP - 1529 ER - TY - JOUR ID - soton356344 UR - https://eprints.soton.ac.uk/356344/ A1 - Thierens, M. A1 - Browning, E. A1 - Pirlet, H. A1 - Loutre, M.-F. A1 - Dorschel, B. A1 - Huvenne, V.A.I. A1 - Titschack, J. A1 - Colin, C. A1 - Foubert, A. A1 - Wheeler, A.J. Y1 - 2013/08/01/ N2 - Through the interplay of a stabilising cold-water coral framework and a dynamic sedimentary environment, cold-water coral carbonate mounds create distinctive centres of bio-geological accumulation in often complex (continental margin) settings. The IODP Expedition 307 drilling of the Challenger Mound (eastern Porcupine Seabight; NE Atlantic) not only retrieved the first complete developmental history of a coral carbonate mound, it also exposed a unique, Early-Pleistocene sedimentary sequence of exceptional resolution along the mid-latitudinal NE Atlantic margin.

In this study, a comprehensive assessment of the Challenger Mound as an archive of Quaternary palaeo-environmental change and long-term coral carbonate mound development is presented. New and existing environmental proxy records, including clay mineralogy, planktonic foraminifer and calcareous nannofossil biostratigraphy and assemblage counts, planktonic foraminifer oxygen isotopes and siliciclastic particle-size, are thereby discussed within a refined chronostratigraphic and climatic context.

Overall, the development of the Challenger Mound shows a strong affinity to the Plio-Pleistocene evolution of the Northern Hemisphere climate system, albeit not being completely in phase with it. The two major oceanographic and climatic transitions of the Plio-Pleistocene ? the Late Pliocene/Early Pleistocene intensification of continental ice-sheet development and the mid-Pleistocene transition to the more extremely variable and more extensively glaciated late Quaternary ? mark two major thresholds in Challenger Mound development: its Late Pliocene (>2.74 Ma) origin and its Middle?Late Pleistocene to recent decline. Distinct surface-water perturbations (i.e. water-mass/polar front migrations, productivity changes, melt-water pulses) are identified throughout the sequence, which can be linked to the intensity and extent of ice development on the nearby British?Irish Isles since the earliest Pleistocene. Glaciation-induced shifts in surface-water primary productivity are thereby proposed to fundamentally control cold-water coral growth, which in turn influences on-mound sediment accumulation and, hence, coral carbonate mound development throughout the Pleistocene. As local factors, such as proximal ice-sheet dynamics and on-mound changes in cold-water coral density, significantly affected the development of the Challenger Mound, they can potentially explain the nature of its palaeo-record and its offsets with the periodicities of global climate variability. On the other hand, owing to this unique setting, a regionally exceptional, high-resolution palaeo-record of Early Pleistocene (ca 2.6 to 2.1 Ma) environmental change (including early British?Irish ice-sheet development), broadly in phase with the 41 ka-paced global climate system, is preserved in the lower Challenger Mound. All in all, the Challenger Mound record highlights the wider relevance of coral carbonate mound archives and their potential to capture unique records from dynamic (continental margin) environments. JF - Quaternary Science Reviews VL - 73 KW - Coral carbonate mound KW - Calcareous nannofossils KW - Planktonic foraminifers KW - Clay minerals KW - Plio-Pleistocene climate KW - NE Atlantic SN - 0277-3791 TI - Cold-water coral carbonate mounds as unique palaeo-archives: the Plio-Pleistocene Challenger Mound record (NE Atlantic) SP - 14 AV - none EP - 30 ER - TY - JOUR ID - soton44127 UR - https://eprints.soton.ac.uk/44127/ IS - 14-16 A1 - Thomalla, S. A1 - Turnewitsch, R. A1 - Lucas, M. A1 - Poulton, A. Y1 - 2006/// N2 - Subtropical ocean gyres are believed to be characterized by low carbon export from the surface into the deep ocean. However, due to their large areas, even relatively small average export could be of significance for the global carbon cycle. To better constrain carbon export from the surface ocean in such regions, radioactive disequilibria between the particle-reactive, short-lived radionuclide 234Th (half-life 24.1 d) and its parent 238U were used to estimate fluxes of 234Th and particulate organic carbon (POC) from surface waters of the North and South Atlantic subtropical gyres and their fringes. Samples were collected between 50°S and 50°N as part of the Atlantic Meridional Transect (AMT) programme during April/May 2004 (AMT14). Application of a steady-state model to the 234Th data revealed particle export from the surface (234Th deficit) and, in one instance, some evidence for shallow particle remineralisation at depth (234Th excess). Export fluxes of POC were calculated from water column 234Th /238U disequilibria and the POC to 234Th ratios on large rapidly sinking particles (>50 ?m). Based on latitudinal distributions of selected hydrographic and biological parameters within the topmost 300 m of the water column, the transect was divided into six regions: ?temperate? (35°?50°N and 35°?50°S), ?oligotrophic? (20°?35°N and 5°?35°S), ?equatorial? (5°S?5°N), and ?upwelling? (5°?20°N). The lowest 234Th-derived POC export fluxes were found in the oligotrophic gyres and ranged from 0 in the northern to 6 mmol C m?2 d?1 in the southern oligotrophic, indicating a tightly coupled food web. Enhanced POC export was associated with the equatorial region (25 mmol C m?2 d?1) and the upwelling region north of the equator (15 mmol C m?2 d?1). POC export in the temperate regions ranged from 7 mmol C m?2 d?1 to a maximum of 41 mmol C m?2 d?1. High fluxes at the poleward edges of the oligotrophic gyres probably result from episodic nutrient-loading processes associated with submesoscale features. Estimates of instantaneous primary production (PP) were compared with 234Th-derived POC export, the latter bearing information from the past few weeks. Most export efficiencies that were calculated based on this comparison were high (10 s%), suggesting uncoupling of PP and export estimates due to the different time scales of the approaches. Moreover, this uncoupling points to the occurrence of pulsed high-export events that could be easily missed by instantaneous sampling but traced by temporally quasi-integrating tracers such as 234Th. Results from this study suggest that although carbon export in the oligotrophic centres of the gyres may be low, carbon sequestration in the temperate fringes of the gyres as well as in the equatorial and upwelling regions can be substantial, and that spatio?temporal variability in these areas of the world's oceans needs to be considered more fully in the context of global oceanic carbon sequestration.
JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 53 KW - radioactive 234Th/238U disequilibrium KW - particle flux KW - carbon export KW - Ssubtropical gyre KW - Atlantic Meridional Transect KW - Atlantic Ocean SN - 0967-0645 TI - Particulate organic carbon export from the North and South Atlantic gyres: the 234Th/238U disequilibrium approach SP - 1629 AV - none EP - 1648 ER - TY - JOUR ID - soton24576 UR - https://eprints.soton.ac.uk/24576/ IS - 1-2 A1 - Thomson, J. A1 - Green, D.R.H. A1 - van Calsteren, P. A1 - Richter, T.O. A1 - van Weering, T.C.E. Y1 - 2006/// N2 - Radiocarbon and 230Thexcess measurements were undertaken on the sediments from fifteen box cores recovered between 48?58°N and 12?22°W at water depths of 1100?4500 m in the northeast Atlantic. Eight of the cores were from Feni Drift in the Rockall Trough at depths of 1700?2500 m and the remaining seven formed an approximate north/south transect at various water depths from the abyssal plain north on to Rockall Plateau. Mean Holocene sediment accumulation fluxes for all cores were established from profiles of bulk sediment radiocarbon age against depth to be in the range 3?7 cm ky? 1 off the Drift and 4?23 cm ky? 1 on the Drift. When compared with these radiocarbon-based sediment accumulation rates, precision measurements of 230Th reveal that the 230Thexcess levels present in the sediments match or slightly exceed the potential supply from the vertically overlying water column in a majority of the cores. One core from the open abyssal plain that had the lowest radiocarbon-based accumulation rate in the entire set also had a close balance between predicted and measured 230Thexcess values. With the assumption that only 230Thexcess produced in the overlying water column is supplied to the sediments, the 230Thexcess values in this core and the other six containing carbonate ooze sediments all imply a rather constant regionally averaged sedimentation flux of 2.0 ± 0.2 (1?, n = 7, min. 1.8, max. 2.3) g cm? 2 ky? 1 rather than matching the 230Thexcess fluxes implied by the radiocarbon data. This singular value is similar to the mean Holocene flux reported for the northeast Atlantic by previous work that utilized the 230Thexcess method, although it is somewhat lower than estimates for the Holocene based on oxygen isotope stratigraphy or radiocarbon methods. The current transport processes that result in the high sediment accumulation rates on Feni Drift have also resulted in a compositional fractionation of the sediments. All sediments from Feni Drift have lower CaCO3 contents than the remainder of the sediments studied, and these are accompanied by lower 230Thexcess specific activities than are found at comparable water column depths elsewhere on the transect. Consistently higher and more variable regional sediment accumulation fluxes are therefore calculated from the Feni Drift 230Thexcess data with the constant flux assumption (average 2.8 ± 0.4 g cm? 2 ky? 1; n = 8, min. 2.3, max. 3.3), some 40% higher than the constant value measured in the other cores. It seems likely that the mean sediment accumulation flux at Feni Drift inside Rockall Trough is consistently higher than on the open ocean margin of the basin, so that the regionally averaged sedimentation fluxes indicated for the Drift by the measured 230Thexcess data are also consistently higher than the singular value measured elsewhere in the northeast Atlantic. JF - Earth and Planetary Science Letters VL - 242 KW - 230Th dating KW - radiocarbon dating KW - deep-sea sediments KW - Feni Drift KW - NE Atlantic Ocean SN - 0012-821X TI - Holocene sediment deposition on a NE Atlantic transect including Feni Drift quantified by radiocarbon and 230Thexcess methods SP - 170 AV - none EP - 185 ER - TY - JOUR ID - soton7874 UR - https://eprints.soton.ac.uk/7874/ IS - 49, Supplement A1 - Thurnherr, A.M. A1 - Richards, K.J. A1 - German, C.R. A1 - Lane-Serff, G.F. Y1 - 1999/// JF - EOS: Transactions American Geophysical Union VL - 80 KW - FLUID DYNAMICS KW - RIFT VALLEYS KW - MID ATLANTIC RIDGE SN - 0096-3941 TI - Dynamics of the flow within a rift valley segment of the Mid-Atlantic Ridge (abstract of paper to be presented at AGU/ASLO 2000 Ocean Sciences Meeting, San Antonio, TX, 24-28 January 2000) AV - none ER - TY - JOUR ID - soton5989 UR - http://ams.allenpress.com/amsonline/?request=get-abstract&issn=1520-0485&volume=32&page=1763 IS - 6 A1 - Thurnherr, A.M. A1 - Richards, K.J. A1 - German, C.R. A1 - Lane-Serff, G.F. A1 - Speer, K.G. Y1 - 2002/// N2 - High levels of diapycnal mixing and geothermal heating near midocean ridges contribute to the buoyancy fluxes that are required to close the global circulation. In topographically confined areas, such as the deep median valleys of slow-spreading ridges, these fluxes strongly influence the local hydrography and dynamics. Data from a segment-scale hydrographic survey of the rift valley of the Mid-Atlantic Ridge and from an array of current meters deployed there during an entire year are analyzed in order to characterize the dominant hydrographic patterns and dynamical processes. Comparison with historic hydrographic data indicates that the temporal variability during the last few decades has been small compared to the observed segment-scale gradients. The rift valley circulation is characterized by inflow from the eastern ridge flank and persistent unidirectional along-segment flow into a cul-de-sac. Therefore, most of the water flowing along the rift valley upwells within the segment with a mean vertical velocity >10?5 m s?1. The observed streamwise hydrographic gradients indicate that diapycnal mixing dominates the rift valley buoyancy fluxes by more than an order of magnitude, in spite of the presence of a large hydrothermal vent field supplying several gigawatts of heat to the water column. Hydrographic budgets in the rift valley yield diffusivity values of order 5 × 10?3 m2 s?1, consistent with estimates derived from statically unstable overturns, the largest of which were observed downstream of topographic obstacles in the path of the along-segment flow. This suggests vertical shear associated with cross-sill flows as the dominant contributor to the mechanical mixing in the rift valley. JF - Journal of Physical Oceanography VL - 32 KW - WOCE KW - MID ATLANTIC RIDGE KW - DIAPYCNAL MIXING KW - HYDROGRAPHY KW - HEAT EXCHANGE SN - 0022-3670 TI - Flow and mixing in the rift valley of the Mid-Atlantic Ridge SP - 1763 AV - none EP - 1778 ER - TY - JOUR ID - soton66836 UR - https://eprints.soton.ac.uk/66836/ IS - 15 A1 - Tilstone, Gavin A1 - Smyth, Timothy A1 - Poulton, Alex A1 - Hutson, Rory Y1 - 2009/07/01/ N2 - Primary production (PP) was determined using 14C uptake at 117 stations in the Atlantic Ocean to validate three PP satellite algorithms of varying complexity. An empirical satellite algorithm based on log chlorophyll-a had the highest bias and root-mean square error compared with measured 14C PP and tended to under-estimate PP. The vertical generalised production model improved PP estimates and was the most accurate algorithm in the Eastern Tropical Atlantic (ETRA) and Western Tropical Atlantic (WTRA), but tended to over-estimate PP in eutrophic provinces. A photosynthesis-light wavelength-resolved model was the most accurate over the Atlantic basin, having the lowest mean log-difference error, root-mean square error and bias, and exhibited a superior performance in six out of the nine ecological provinces surveyed. Using this algorithm and mean monthly SeaWiFS fields, a PP time series was generated for the Atlantic Ocean from 1998 to 2005 which was compared with Advanced Very High Resolution Radiometer (AVHRR) sea-surface temperature (SST) data. There was a significant negative correlation between SST and PP in the North Atlantic Subtropical Gyre Province (NAST), North Atlantic Tropical Gyre (NATR), and WTRA suggesting that recent warming trends in these provinces are coupled with a decrease in phytoplankton production.

JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 56 KW - Phytoplankton KW - Photosynthesis KW - Primary production KW - Atlantic Ocean KW - Satellite oceanography KW - Remote sensing SN - 0967-0645 TI - Measured and remotely sensed estimates of primary production in the Atlantic Ocean from 1998 to 2005 SP - 918 AV - none EP - 930 ER - TY - JOUR ID - soton69427 UR - http://www.agu.org/journals/gb/gb0904/2008GB003389/ A1 - Torres-Valdés, S. A1 - Roussenov, V.M. A1 - Sanders, R. A1 - Reynolds, S. A1 - Pan, X. A1 - Mather, R. A1 - Landolfi, A. A1 - Wolff, G.A. A1 - Achterberg, E.P. A1 - Williams, R.G. Y1 - 2009/// N2 - A synthesis is provided of dissolved organic nitrogen (DON) and phosphorus (DOP) distributions over the Atlantic Ocean based upon field data from eight recent transects, six meridional between 50°N and 50°S and two zonal at 24° and 36°N. Over the entire tropical and subtropical Atlantic, DON and DOP provide the dominant contributions to total nitrogen and phosphorus pools for surface waters above the thermocline. Elevated DON and DOP concentrations (>5 and >0.2 ?mol L?1, respectively) occur in surface waters on the eastern side of the North Atlantic subtropical gyre and equatorial sides of both the North and South Atlantic subtropical gyres, while particularly low concentrations of DOP (<0.05 ?mol L?1) occur over the northern flank of the North Atlantic subtropical gyre along 36°N. This distribution is consistent with organic nutrients formed at the gyre margins supporting carbon export as they are redistributed via the gyre circulation. The effect of DON and DOP transport and cycling on export production is examined in an eddy-permitting, coupled physical and nutrient model integrated for 40 years: organic nutrients are produced in the upwelling zones off North Africa and transferred laterally into the gyre interior, facilitated in part by the mesoscale eddy circulation, as well as fluxed northward from the tropics as part of the overturning circulation. Inputs of semilabile DON and DOP to the tropical and subtropical Atlantic Ocean play an important role in sustaining up to typically 40 and 70% of the modeled particulate N and P export, particularly on the eastern and equatorward sides of the subtropical gyres.
JF - Global Biogeochemical Cycles VL - 23 KW - dissolved organic nutrients KW - export production KW - Atlantic Ocean SN - 0886-6236 TI - Distribution of dissolved organic nutrients and their effect on export production over the Atlantic Ocean AV - none ER - TY - JOUR ID - soton64364 UR - http://www.springerlink.com/content/72072w1522234805/?p=34735c24bc7d4584a18d8af62971e424&pi=7 IS - 5-6 A1 - Treguier, Anne Marie A1 - Gourcuff, Claire A1 - Lherminier, Pascale A1 - Mercier, Herle A1 - Barnier, Bernard A1 - Madec, Gurvan A1 - Molines, Jean-Marc A1 - Penduff, Thierry A1 - Czeschel, Lars A1 - Boning, Claus Y1 - 2006/12// N2 - Numerical models are used to estimate the meridional overturning and transports along the paths of two hydrographic cruises, carried out in 1997 and 2002 from Greenland to Portugal. We have examined the influence of the different paths of the two cruises and found that it could explain 0.4 to 2 Sv of difference in overturning (the precise value is model-dependent). Models show a decrease in the overturning circulation between 1997 and 2002, with different amplitudes. The CLIPPER ATL6 model reproduces well the observed weakening of the overturning in density coordinates between the cruises; in the model, the change is due to the combination of interannual and high-frequency forcing and internal variability associated with eddies and meanders. Examination of the -coordinate overturning reveals model?data discrepancies: the vertical structure in the models does not change as much as the observed one. The East Greenland current variability is mainly wind-forced in the ATL6 model, while fluctuations due to eddies and instabilities explain a large part of the North Atlantic Current variability. The time-residual transport of dense water and heat due to eddy correlations between currents and properties is small across this section, which is normal to the direction of the main current. JF - Ocean Dynamics VL - 56 KW - Oceanography KW - Climate variability KW - North Atlantic KW - Thermohaline circulation KW - Ocean model SN - 1616-7341 TI - Internal and forced variability along a section between Greenland and Portugal in the CLIPPER Atlantic model SP - 568 AV - none EP - 580 ER - TY - JOUR ID - soton366927 UR - https://eprints.soton.ac.uk/366927/ IS - 1787 A1 - Trueman, C.N. A1 - Johnston, G. A1 - O'Hea, B. A1 - MacKenzie, K.M. Y1 - 2014/07/22/ N2 - Biological transfer of nutrients and materials between linked ecosystems influences global carbon budgets and ecosystem structure and function. Identifying the organisms or functional groups that are responsible for nutrient transfer, and quantifying their influence on ecosystem structure and carbon capture is an essential step for informed management of ecosystems in physically distant, but ecologically linked areas. Here, we combine natural abundance stable isotope tracers and survey data to show that mid-water and bentho-pelagic-feeding demersal fishes play an important role in the ocean carbon cycle, bypassing the detrital particle flux and transferring carbon to deep long-term storage. Global peaks in biomass and diversity of fishes at mid-slope depths are explained by competitive release of the demersal fish predators of mid-water organisms, which in turn support benthic fish production. Over 50% of the biomass of the demersal fish community at depths between 500 and 1800 m is supported by biological rather than detrital nutrient flux processes, and we estimate that bentho-pelagic fishes from the UK?Irish continental slope capture and store a volume of carbon equivalent to over 1 million tonnes of CO2 every year. JF - Proceedings of the Royal Society B: Biological Sciences VL - 281 KW - benthic?pelagic coupling KW - food web KW - North Atlantic KW - carbon KW - nitrogen KW - mesopelagic SN - 0962-8452 TI - Trophic interactions of fish communities at midwater depths enhance long-term carbon storage and benthic production on continental slopes AV - none EP - 10 ER - TY - JOUR ID - soton340662 UR - https://eprints.soton.ac.uk/340662/ IS - 5 A1 - Trueman, C.N. A1 - MacKenzie, K.M. A1 - Palmer, M.R. Y1 - 2012/07// N2 - An 18-year record of stable isotopes from Atlantic salmon (Salmo salar) migrating to two different regions of the North Atlantic reveals climate-driven subdecadal variations. Time-series of carbon isotopes in one salmon stock, thought to feed in the Faroes/Iceland Basin area, show Subpolar Gyre (SPG) modal variability, which is not seen in fish feeding in the Norwegian Sea. At times of weak SPG circulation, when waters in the Iceland Basin are relatively warm, carbon isotope values are somewhat negative, suggesting possible changes in phytoplankton community structure. The fluctuations in plankton community dynamics suggested by the stable isotope values are coincident with fluctuations in the estimates of marine mortality in one sea-winter fish feeding in the Norwegian Sea, but not in those feeding in the Iceland Basin. Marine mortality in salmon feeding in the Iceland Basin is therefore likely to be more strongly influenced by factors other than bottom?up control. Time-series analysis of stable isotopes in consumer tissues provides information on the interaction between climate and ecosystem dynamics on the scale of individual stocks and cohorts. JF - ICES Journal of Marine Science VL - 69 KW - ecosystem KW - NE Atlantic KW - salmon KW - time-series SN - 1054-3139 TI - Stable isotopes reveal linkages between ocean climate, plankton community dynamics, and survival of two populations of Atlantic salmon (Salmo salar) SP - 784 AV - none EP - 794 ER - TY - JOUR ID - soton8885 UR - http://www.agu.org/journals/gl/gl0012/1999GL007004/pdf/1999GL007004.pdf IS - 12 A1 - Tsimplis, M.N. A1 - Baker, T.F. Y1 - 2000/// JF - Geophysical Research Letters VL - 27 KW - NORTH ATLANTIC OSCILLATION KW - MEDITERRANEAN DEEP WATER KW - MEDITERRANEAN SEA KW - NAO KW - SEA LEVEL CHANGES KW - SALINITY KW - TEMPERATURE KW - TEMPORAL VARIATIONS SN - 0094-8276 TI - Sea level drop in the Mediterranean Sea: an indicator of deep water salinity and temperature changes? SP - 1731 AV - none EP - 1734 ER - TY - JOUR ID - soton353608 UR - https://eprints.soton.ac.uk/353608/ IS - 2 A1 - Tsimplis, M.N. A1 - Calafat, F.M. A1 - Marcos, M. A1 - Jordà, G. A1 - Gomis, D. A1 - Fenoglio-Marc, L. A1 - Struglia, M.V. A1 - Josey, S.A. A1 - Chambers, D.P. Y1 - 2013/02// N2 - Sea level in the Mediterranean Sea over the period 1993?2011 is studied on the basis of altimetry, temperature, and salinity data and gravity measurements from Gravity Recovery and Climate Experiment (GRACE) (2002?2010). An observed increase in sea level corresponds to a linear sea level trend of 3.0?±?0.5?mm/yr dominated by the increase in the oceanic mass in the basin. The increase in sea level does not, however, take place linearly but over two 2?3?year periods, each contributing 2?3?cm of sea level. Variability in the basin sea level and its mass component is dominated by the winter North Atlantic Oscillation (NAO). The NAO influence on sea level is primarily linked with atmospheric pressure changes and local wind field changes. However, neither the inverse barometer correction nor a barotropic sea level model forced by atmospheric pressure and wind can remove fully the NAO influence on the basin sea level. Thus, a third contributing mechanism linked with the NAO is suggested. During winter 2010, a low NAO index caused a basin sea level increase of 12?cm which was almost wholly due to mass changes and is evidenced by GRACE. About 8?cm of the observed sea level change can be accounted for as due to atmospheric pressure and wind changes. The residual 4?cm of sea level change is caused by the newly identified contribution. The physical mechanisms that may be responsible for this additional contribution are discussed. JF - Journal of Geophysical Research: Oceans VL - 118 KW - sea level KW - North Atlantic Oscillation KW - Mediterranean Sea KW - mass addition SN - 2169-9275 TI - The effect of the NAO on sea level and on mass changes in the Mediterranean Sea SP - 944 AV - public EP - 952 ER - TY - JOUR ID - soton7893 UR - http://www.agu.org/journals/gl/gl0105/2000GL012098/pdf/2000GL012098.pdf IS - 5 A1 - Tsimplis, M.N. A1 - Josey, S.A. Y1 - 2001/// JF - Geophysical Research Letters VL - 28 KW - WOCE KW - MEDITERRANEAN SEA KW - NORTH ATLANTIC KW - OSCILLATIONS KW - SEA LEVEL VARIABILITY KW - ATMOSPHERIC FORCING KW - OCEAN RESPONSE SN - 0094-8276 TI - Forcing of the Mediterranean Sea by atmospheric oscillations over the North Atlantic SP - 803 AV - none EP - 806 ER - TY - JOUR ID - soton11160 UR - https://eprints.soton.ac.uk/11160/ IS - C8 A1 - Tsimplis, M.N. A1 - Josey, S.A. A1 - Rixen, M. A1 - Stanev, E.V. Y1 - 2004/08// N2 - Forcing mechanisms for sea level variability in the Black Sea are investigated in the context of an observed increase in the sea level of this basin by 2.5 mm/yr over the last 60 years. Temperature and salinity variations computed from the Mediterranean Data Archeology and Rescue (MEDAR) data set exhibit significant interdecadal variability. However, the corresponding steric height variation does not show a long-term increase and thus cannot account for the observed change in sea level. The impact of surface freshwater flux (P-E) changes is also investigated using two independent data sets. The first data set, which is based on measurements collected in the basin, can explain most of the sea level variability, with only 0.8 mm/yr remaining unexplained. The second data set, output from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis, is unable to explain any of the observed trend. Potential contributions from changes in river runoff and surface pressure are quantified but found to be minor terms. By comparing the observed salinity changes with the sea level rise and the P-E variability in the first data set, we infer that the P-E variations are the primary cause for the observed sea level rise, while land movements are likely to partly contribute, too. The relationship of Black Sea temperature and salinity variability with corresponding variability in the connected Aegean Sea has also been explored. A significant correlation is found between the salinity of the upper water of the Aegean Sea and the layer between 50 and 300 m in the Black Sea, indicating that the latter layer is a product of the Mediterranean inflow. JF - Journal of Geophysical Research VL - 109 KW - climatology KW - steric sea level KW - North Atlantic Oscillation KW - interbasin water and salt exchange KW - Black Sea SN - 0148-0227 TI - On the forcing of sea level in the Black Sea SP - C08015 AV - none EP - [14pp] ER - TY - JOUR ID - soton24085 UR - https://eprints.soton.ac.uk/24085/ IS - 1841 A1 - Tsimplis, M.N. A1 - Shaw, A.G.P. A1 - Flather, R.A. A1 - Woolf, D.K. Y1 - 2006/// N2 - The thermosteric contribution of the North Atlantic Oscillation (NAO) to the North Sea sea-level for the winter period is investigated. Satellite sea surface temperature as well as in situ measurements are used to define the sensitivity of winter water temperature to the NAO as well as to determine the trends in temperature. The sea surface temperature sensitivity to the NAO is about 0.85°C per unit NAO, which results in thermosteric sea-level changes of about 1?2cm per unit NAO. The sensitivity of sea surface temperatures to the NAO is strongly time-dependent. Model data from a two-dimensional hydrodynamic tide+surge model are used in combination with the estimated thermosteric anomalies to explain the observed sea-level changes and, in particular, the sensitivity of the datasets to the NAO variability. The agreement between the model and the observed data is improved by the inclusion of the thermosteric effect. JF - Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences VL - 364 KW - sea-level KW - North Atlantic Oscillation KW - thermosteric effect KW - decadal climate variability KW - sea surface temperature KW - tide+surge model SN - 1364-503X TI - The influence of the North Atlantic Oscillation on the sea level around the northern European coasts reconsidered: the thermosteric effects SP - 845 AV - none EP - 856 ER - TY - JOUR ID - soton17495 UR - https://eprints.soton.ac.uk/17495/ IS - 1831 A1 - Tsimplis, M.N. A1 - Woolf, D.K. A1 - Osborn, T.J. A1 - Wakelin, S. A1 - Wolf, J. A1 - Flather, R. A1 - Shaw, A.G.P. A1 - Woodworth, P. A1 - Challenor, P. A1 - Blackman, D. A1 - Pert, F. A1 - Yan, Z. A1 - Jevrejeva, S. Y1 - 2005/06/15/ N2 - Within the framework of a Tyndall Centre research project, sea level and wave changes around the UK and in the North Sea have been analysed. This paper integrates the results of this project. Many aspects of the contribution of the North Atlantic Oscillation (NAO) to sea level and wave height have been resolved. The NAO is a major forcing parameter for sea-level variability. Strong positive response to increasing NAO was observed in the shallow parts of the North Sea, while slightly negative response was found in the southwest part of the UK. The cause of the strong positive response is mainly the increased westerly winds. The NAO increase during the last decades has affected both the mean sea level and the extreme sea levels in the North Sea. The derived spatial distribution of the NAO-related variability of sea level allows the development of scenarios for future sea level and wave height in the region. Because the response of sea level to the NAO is found to be variable in time across all frequency bands, there is some inherent uncertainty in the use of the empirical relationships to develop scenarios of future sea level. Nevertheless, as it remains uncertain whether the multi-decadal NAO variability is related to climate change, the use of the empirical relationships in developing scenarios is justified. The resulting scenarios demonstrate: (i) that the use of regional estimates of sea level increase the projected range of sea-level change by 50% and (ii) that the contribution of the NAO to winter sea-level variability increases the range of uncertainty by a further 10?20cm. On the assumption that the general circulation models have some skill in simulating the future NAO change, then the NAO contribution to sea-level change around the UK is expected to be very small (<4cm) by 2080. Wave heights are also sensitive to the NAO changes, especially in the western coasts of the UK. Under the same scenarios for future NAO changes, the projected significant wave-height changes in the northeast Atlantic will exceed 0.4m. In addition, wave-direction changes of around 20° per unit NAO index have been documented for one location. Such changes raise the possibility of consequential alteration of coastal erosion. JF - Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences VL - 363 KW - sea level KW - waves KW - north atlantic oscillation KW - regional variability KW - scenarios SN - 1364-503X TI - Towards a vulnerability assessment of the UK and northern European coasts: the role of regional climate variability SP - 1329 AV - none EP - 1358 ER - TY - JOUR ID - soton414023 UR - https://eprints.soton.ac.uk/414023/ IS - 7 A1 - Turk, Kendra A. A1 - Rees, Andrew P. A1 - Zehr, Jonathan P. A1 - Pereira, Nicole A1 - Swift, Paul A1 - Shelley, Rachel A1 - Lohan, Maeve A1 - Woodward, E. Malcolm S A1 - Gilbert, Jack Y1 - 2011/07// N2 -

Expression of nifH in 28 surface water samples collected during fall 2007 from six stations in the vicinity of the Cape Verde Islands (north-east Atlantic) was examined using reverse transcription-polymerase chain reaction (RT-PCR)-based clone libraries and quantitative RT-PCR (RT-qPCR) analysis of seven diazotrophic phylotypes. Biological nitrogen fixation (BNF) rates and nutrient concentrations were determined for these stations, which were selected based on a range in surface chlorophyll concentrations to target a gradient of primary productivity. BNF rates greater than 6 nmolNl-1 h -1 were measured at two of the near-shore stations where high concentrations of Fe and PO43- were also measured. Six hundred and five nifH transcripts were amplified by RT-PCR, of which 76% are described by six operational taxonomic units, including Trichodesmium and the uncultivated UCYN-A, and four non-cyanobacterial diazotrophs that clustered with uncultivated Proteobacteria. Although all five cyanobacterial phylotypes quantified in RT-qPCR assays were detected at different stations in this study, UCYN-A contributed most significantly to the pool of nifH transcripts in both coastal and oligotrophic waters. A comparison of results from RT-PCR clone libraries and RT-qPCR indicated that a ?-proteobacterial phylotype was preferentially amplified in clone libraries, which underscores the need to use caution interpreting clone-library-based nifH studies, especially when considering the importance of uncultivated proteobacterial diazotrophs.

JF - The ISME Journal VL - 5 KW - Atlantic KW - Cape Verde KW - molecular KW - nifH KW - nitrogen fixation KW - nitrogenase SN - 1751-7362 TI - Nitrogen fixation and nitrogenase (nifH) expression in tropical waters of the eastern North Atlantic SP - 1201 AV - none EP - 1212 ER - TY - JOUR ID - soton49889 UR - https://eprints.soton.ac.uk/49889/ IS - 3-4 A1 - Turnewitsch, R. A1 - Springer, B.M. A1 - Kiriakoulakis, K. A1 - Vilas, J.C. A1 - Aristegui, J. A1 - Wolff, G. A1 - Peine, F. A1 - Werk, S. A1 - Graf, G. A1 - Waniek, J.J. Y1 - 2007/06// N2 - Particulate matter in aquatic systems is an important vehicle for the transport of particulate organic carbon (POC). Its accurate measurement is of central importance for the understanding of marine carbon cycling. Previous work has shown that GF/F-filter-based bottle-sample-derived concentration estimates of POC are generally close to or higher than large-volume in-situ-pump-derived values (and in some rare cases in subzero waters are up to two orders of magnitude higher). To further investigate this phenomenon, water samples from the surface and mid-water Northeast Atlantic and the Baltic Sea were analyzed. Our data support a bias of POC concentration estimates caused by adsorption of nitrogen-rich dissolved organic material onto GF/F filters. For surface-ocean samples the mass per unit area of exposed filter and composition of adsorbed material depended on the filtered volume. Amounts of adsorbed OC were enhanced in the surface ocean (typically 0.5 ?mol cm? 2 of exposed filter) as compared to the deep ocean (typically 0.2 ?mol cm? 2 of exposed filter). These dependencies should be taken into account for future POC methodologies. Bottle/pump differences of samples that were not corrected for adsorption were higher in the deep ocean than in the surface ocean. This discrepancy increased in summer. It is shown that POC concentration estimates that were not corrected for adsorption depend not only on the filtered volume, true POC concentration and mass of adsorbed OC, but also on the filter area. However, in all cases we studied, correction for adsorption was important, but not sufficient, to explain bottle/pump differences. Artificial formation of filterable particles and/or processes leading to filterable material being lost from and/or missed by sample-processing procedures must be considered. It can be deduced that the maximum amounts of POC and particulate organic nitrogen (PON) that can be artificially formed per liter of filtered ocean water are 3?4 ?M OC (5?10% of dissolved OC) and 0.2?0.5 ?M ON (2?10% of dissolved ON), respectively. The relative sensitivities of bottle and pump procedures, and of surface- and deep-ocean material, to artificial particle formation and the missing/losing of material are evaluated. As present procedures do not exist to correct for all possible biasing effects due to artificial particle formation and/or miss/loss of filterable material, uncertainties of filtration-based estimates of POC concentrations need further testing. The challenge now is to further constrain the magnitude of the biasing effects that add to the adsorption effect to reduce the uncertainties of estimates of POC concentrations, inventories and fluxes in the ocean. JF - Marine Chemistry VL - 105 KW - Particulate organic carbon KW - Dissolved organic matter KW - Adsorption KW - Filtration KW - Bottles KW - Pumps KW - Baltic Sea KW - Northeast Atlantic SN - 0304-4203 TI - Determination of particulate organic carbon (POC) in seawater: The relative methodological importance of artificial gains and losses in two glass-fiber-filter-based techniques SP - 208 AV - none EP - 228 ER - TY - JOUR ID - soton64155 UR - https://eprints.soton.ac.uk/64155/ IS - 12 A1 - Turnewitsch, Robert A1 - Reyss, Jean-Louis A1 - Nycander, Jonas A1 - Waniek, Joanna J. A1 - Lampitt, Richard S. Y1 - 2008/12// N2 - Residual flow, barotropic tides and internal (baroclinic) tides interact in a number of ways with kilometer-scale seafloor topography such as abyssal hills and seamounts. Because of their likely impact on vertical mixing such interactions are potentially important for ocean circulation and the mechanisms and the geometry of these interactions are a matter of ongoing studies. In addition, very little is known about how these interactions are reflected in the sedimentary record. This multi-year study investigates if flow/topography interactions are reflected in distributional patterns of the natural short-lived (half-life: 24.1 d) particulate-matter tracer 234Th relative to its conservative (non-particle-reactive) and very long-lived parent nuclide 238U. The sampling sites were downstream of, or surrounded by, fields of short seamounts and, therefore, very likely to be influenced by nearby flow/topography interactions. At the sampling sites between about 200 and 1000 m above the seafloor recurrent ?fossil? disequilibria were detected. ?Fossil? disequilibria are defined by clearly detectable 234Th/238U disequilibria (total 234Th radioactivity <238U radioactivity, indicating a history of intense particulate 234Th scavenging and particulate-matter settling from the sampled parcel of water) and conspicuously low particle-associated 234Th activities. ?Fossil? disequilibria were centered at levels in the water column that correspond to the average height of the short seamounts near the sampling sites. This suggests the ?fossil? disequilibria are formed on the seamount slopes. Moreover, the magnitude of the ?fossil? disequilibria suggests that the slopes of the short seamounts in the study region are characterized by particularly vigorous fluid dynamics. Since ?fossil? disequilibria already occurred at O(1?10 km) away from the seamount slopes it is likely that these vigorous fluid dynamics rapidly decay away from the slopes on scales of O(1?10 km). These conclusions are supported by the horizontal distribution and magnitude of the modeled total (barotropic+baroclinic) tidal current velocities of the predominating tidal M2 constituent: on (near-)critical seamount slopes baroclinic tides lead to localized [O(1 km)] increases of the overall tidal current velocity by a factor of 2, thereby pushing the total current velocity well above the threshold for sediment erosion. The results of this and a previous study [Turnewitsch, R., Reyss, J.-L., Chapman, D.C., Thomson, J., Lampitt, R.S., 2004. Evidence for a sedimentary fingerprint of an asymmetric flow field surrounding a short seamount. Earth and Planetary Science Letters 222(3?4), 1023?1036] show that kilometer-scale flow/topography interactions leave a marine geochemical imprint. This imprint may help develop new sediment proxies for the reconstruction of past changes of fluid dynamics in the deep sea, including residual and tidal flow. Sedimentary records controlled by kilometer-scale seafloor elevations are promising systems for the reconstruction of paleo-changes of deep-ocean fluid dynamics. For the sediment-based reconstruction of paleo-parameters other than physical oceanographic ones it may be advisable to avoid kilometer-scale topography altogether.
JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 55 KW - Thorium-234 KW - Particle dynamics KW - Sediment dynamics KW - Topography KW - Seamounts KW - Internal tides KW - Mid-Atlantic ridge KW - Northeast Atlantic SN - 0967-0637 TI - Internal tides and sediment dynamics in the deep sea - evidence from radioactive 234Th/238U disequilibria SP - 1727 AV - none EP - 1747 ER - TY - JOUR ID - soton476053 UR - https://eprints.soton.ac.uk/476053/ IS - 3 A1 - Turney, Chris S.M. A1 - Jones, Richard T. A1 - Thomas, Zoë A. A1 - Palmer, Jonathan G. A1 - Brown, David N2 - Abandonment of farming systems on upland areas in southwest Britain during the Late Bronze Age ? some 3000 years ago ? is widely considered a ?classic? demonstration of the impact of deteriorating climate on the vulnerability of populations in such marginal environments. Here we test the hypothesis that climate change drove the abandonment of upland areas by developing new chronologies for human activity on upland areas during the Bronze Age across southwest Britain (Dartmoor, Exmoor and Bodmin Moor). We find Bronze Age activity in these areas spanned 3900?2950 calendar years ago with abandonment by 2900 calendar years ago. Holocene Irish bog and lake oak tree populations provide evidence of major shifts in hydroclimate across western Britain and Ireland, coincident with ice rafted debris layers recognized in North Atlantic marine sediments, indicating significant changes in the latitude and intensity of zonal atmospheric circulation across the region. We observe abandonment of upland areas in southwest Britain coinciding with a sustained period of extreme wet conditions that commenced 3100 calendar years ago. Our results are consistent with the view that climate change increased the vulnerability of these early farming communities and led to a less intensive use of such marginal environments across Britain. VL - 13 TI - Extreme wet conditions coincident with Bronze Age abandonment of upland areas in Britain AV - none EP - 79 N1 - Funding Information: We thank numerous colleagues for discussing these ideas with special mention to Mike Baillie. C. S. M. Turney acknowledges the support of the Australian Research Council ( FL100100195 and DP130104156 ). We thank two anonymous reviewers for their constructive comments on an earlier draft of the manuscript. Publisher Copyright: © 2016 Elsevier Ltd Y1 - 2016/03/01/ JF - Anthropocene KW - Dartmoor reaves KW - Human response KW - Irish bog oaks KW - Late Bronze Age KW - Marginal upland environments KW - North Atlantic westerly airflow SN - 2213-3054 SP - 69 ER - TY - JOUR ID - soton2083 UR - https://eprints.soton.ac.uk/2083/ A1 - Turrell, W.R. A1 - Holliday, N.P. Y1 - 2003/// JF - ICES Marine Science Symposia VL - 219 KW - NAO KW - NORTH ATLANTIC OSCILLATION KW - INTERANNUAL VARIABILITY KW - NORTH ATLANTIC TI - The ICES Annual Ocean Climate Status Summary: 2000/2001 SP - 309 AV - none EP - 310 ER - TY - JOUR ID - soton8958 UR - https://eprints.soton.ac.uk/8958/ IS - 4 A1 - Tyler, P.A. A1 - Dixon, D.R. Y1 - 2000/// JF - Journal of the Marine Biological Association of the United Kingdom VL - 80 KW - MID ATLANTIC RIDGE KW - LARVAE KW - HYDROTHERMAL COMMUNITIES SN - 0025-3154 TI - Temperature/pressure tolerance of the first larval stage of Mirocaris fortunata from Lucky Strike hydrothermal vent field SP - 739 AV - none EP - 740 ER - TY - JOUR ID - soton354088 UR - https://eprints.soton.ac.uk/354088/ IS - 10 A1 - Tzortzi, E. A1 - Josey, S.A. A1 - Srokosz, M. A1 - Gommenginger, C. Y1 - 2013/05/28/ N2 - Observations from the SMOS satellite are used to reveal new aspects of Tropical Atlantic sea surface salinity (SSS) variability. Over an annual cycle, the variability is dominated by eastern and western basin SSS ?poles,? with seasonal ranges up to 6.5 pss (practical salinity scale), that vary out of phase by 6 months and largely compensate each other. A much smaller SSS range (0.08 pss) is observed for the region as a whole. The dominant processes controlling SSS variability are investigated using GPCPv2.2 precipitation (P), OAFlux evaporation (E), and Dai and Trenberth river flow (R) data sets. For the western pole, SSS varies in phase with P and lags R by 1?2 months; a more complex relationship holds for the eastern pole. The synthesis of novel satellite SSS data with E, P, and R enables a new approach to determining variability in Tropical freshwater fluxes and its potential impacts on the Atlantic ocean circulation. JF - Geophysical Research Letters VL - 40 KW - Sea surface salinity KW - SMOS KW - Freshwater fluxes KW - Tropical Atlantic KW - Seasonal variability KW - River runoff SN - 0094-8276 TI - Tropical Atlantic salinity variability: New insights from SMOS SP - 2143 AV - public EP - 2147 ER - TY - JOUR ID - soton361695 UR - https://eprints.soton.ac.uk/361695/ IS - 4 A1 - Ussher, Simon J. A1 - Achterberg, Eric P. A1 - Powell, Claire A1 - Baker, Alex R. A1 - Jickells, Tim D. A1 - Torres, Ricardo A1 - Worsfold, Paul J. Y1 - 2013/12// N2 - Dissolved iron (dFe) distributions and atmospheric and vertical subduction fluxes of dFe were determined in the upper water column for two meridional transects of the Atlantic Ocean. The data demonstrate the disparity between the iron biogeochemistry of the North and South Atlantic Ocean and show well-defined gradients of size fractionated iron species in surface waters between geographic provinces. The highest dFe and lowest mixed layer residence times (0.4?2.5 years) were found in the northern tropical and subtropical regions. In contrast, the South Atlantic Gyre had lower dFe concentrations (<0.4 nM) and much longer residence times (>5 years), presumably due to lower atmospheric inputs and more efficient biological recycling of iron in this region. Vertical input fluxes of dFe to surface waters ranged from 20 to 170 nmol m?2 d?1 in the North Atlantic and tropical provinces, whereas average fluxes of 6?13 nmol m?2 d?1 were estimated for the South Atlantic. Our estimates showed that the variable dFe distribution over the surface Atlantic (<0.1?2.0 nM) predominantly reflected atmospheric Fe deposition fluxes (>50% of total vertical Fe flux to surface waters) rather than upwelling or vertical mixing. This demonstrates the strength of the connection between land-derived atmospheric Fe fluxes and the biological cycling of carbon and nitrogen in the Atlantic Ocean. JF - Global Biogeochemical Cycles VL - 27 KW - iron KW - Atlantic Ocean KW - atmospheric deposition KW - aluminum SN - 0886-6236 TI - Impact of atmospheric deposition on the contrasting iron biogeochemistry of the North and South Atlantic Ocean SP - 1096 AV - none EP - 1107 ER - TY - JOUR ID - soton79575 UR - https://eprints.soton.ac.uk/79575/ IS - 1 A1 - Ussher, Simon J. A1 - Achterberg, Eric P. A1 - Sarthou, Géraldine A1 - Laan, Patrick A1 - de Baar, Hein J.W. A1 - Worsfold, Paul J. Y1 - 2010/07// N2 - The distribution of size fractionated dissolved iron (DFe, <0.2 ?m) species was determined in the
upper water column (0-150 m) of the Canary Basin (25 ? 32 ºN and 18 ? 24 ºW) on a research cruise in
October 2002. A DFe concentration gradient resulting from a decrease in both soluble iron (SFe,
<0.02?m) and colloidal iron (CFe, 0.02 ? 0.2 ?m) was shown to extend from the coast of northwest
Africa into the oligotrophic gyre (varying from ~1 nM in the shelf region to 0.15 nM in the most off
shore waters). At the time of this study, the dominant dissolved Fe input to the region was deduced to
be the advection of shelf and upwelled waters rather than Saharan dust deposition.
SFe and CFe fractions had mean concentrations (± standard deviation) of 0.25 ± 0.11 and 0.21 ±
0.16 nM respectively (n = 58). Colloidal iron formed a highly variable fraction of DFe (ca. 0 ? 80%,
mean of 42%) in the region but was less variable in the low iron, oligotrophic intermediate waters
(0.18 ± 0.06 nM, 31.7 ºN, 22.0 ºW, 0 ? 1300 m depth). The high variability found at the most
productive near-shelf stations was driven by biological processing and mixing of different water
masses. In contrast, less variability between SFe and CFe at the remote off shore stations suggested
that vertical variations in the water column were controlled more by chemical partitioning and vertical
particle fluxes with evidence of preferential biological uptake and/or removal of SFe in the most
remote surface waters. JF - Marine Environmental Research VL - 70 KW - Biogeochemical cycle KW - trace elements KW - colloids KW - iron KW - Atlantic Ocean KW - Canary Basin SN - 0141-1136 TI - Distribution of size fractionated dissolved iron in the Canary Basin SP - 46 AV - none EP - 55 ER - TY - JOUR ID - soton41821 UR - https://eprints.soton.ac.uk/41821/ IS - 1-4 A1 - Van Rooij, D. A1 - De Mol, B. A1 - Huvenne, V. A1 - Ivanov, M. A1 - Henriet, J.P. Y1 - 2003/03/30/ N2 - The Porcupine Seabight is an embayment that takes a particular position in the NE Atlantic slope. Sonographs, a few current measurements and hydrodynamic modelling suggest the presence of a strong northward-flowing bottom current, locally enhanced by internal tides, affecting the eastern slope of the Seabight. At this location a province of coral banks is described, expressed as mounds lined up in along-slope-trending ridges. In this paper, very high-resolution single-channel seismic profiles are used to evaluate to what extent the bottom currents influenced the deposition of the sediments surrounding the mounds throughout the Late Cenozoic. Three seismostratigraphic units (P1, P2 and P3) can be identified in the Belgica mound area, separated by two margin-wide discontinuities (RD2 and RD1). Within Unit P1 (probably Early to Middle Miocene) upslope-migrating sediment waves are observed, suggesting strong bottom currents were already active in the Miocene. After an early Middle Miocene erosion event, represented by reflector RD2, an acoustically transparent layer (Unit P2) of as yet unknown lithology was deposited in the studied area. A second margin-wide erosional event, marked by the Late Pliocene RD1 reflector, removed a large part of Unit P2 and has cut deeply into Unit P1. Subsequently, the Belgica mounds were constructed spectacularly fast on topographic irregularities on the RD1 paleobathymetry. The onlap within the Quaternary Unit P3, which surrounds these mounds, suggests that the mounds were already present before the deposition of P3 and were big enough to affect the intensity of the currents around them. Furthermore, the channels and the mounds are, together with the complex oceanographic regime, the key morphological elements responsible for the shaping of a contourite system in the Belgica mound area during the Quaternary. One drift body is formed by an inferred south?north-directed current, with a drift levee and associated channel located on its western side. Between this channel and the mounds, large-scale sediment waves suggest an intensified bottom current running along the foot of the steep flanks of the mounds. The Belgica mounds are embedded in another drift body. Here, an interaction of bottom and turbidity currents is suggested, creating short turbidite channels at the southern and northern flanks of the mounds. Locally, small confined drifts can be observed where Unit P3 is deposited in a narrow passage made by the paleobathymetry of RD1 and the mounds.
JF - Marine Geology VL - 195 KW - bottom current KW - turbidity current KW - seismic stratigraphy KW - Northeast Atlantic KW - Porcupine Seabight KW - Cenozoic KW - mound SN - 0025-3227 TI - Seismic evidence of current-controlled sedimentation in the Belgica mound province, upper Porcupine slope, southwest of Ireland SP - 31 AV - none EP - 53 ER - TY - JOUR ID - soton7868 UR - https://eprints.soton.ac.uk/7868/ IS - 1/4 A1 - Vanreusel, A. A1 - Cosson-Sarradin, N. A1 - Gooday, A.J. A1 - Paterson, G.L.J. A1 - Galeron, J. A1 - Sibuet, M. A1 - Vincx, M. Y1 - 2001/// JF - Progress in Oceanography VL - 50 KW - POLYCHAETES KW - NORTHEAST ATLANTIC OCEAN KW - SAMPLING KW - VERTICAL DISTRIBUTION KW - POPULATION DENSITY KW - BIOLOGY SN - 0079-6611 TI - Evidence for episodic recruitment in a small opheliid polychaete species from the abyssal NE Atlantic SP - 285 AV - none EP - 301 ER - TY - JOUR ID - soton7955 UR - https://eprints.soton.ac.uk/7955/ IS - 1-4 A1 - Vanucci, S. A1 - Dell'Anno, A. A1 - Pusceddu, A. A1 - Fabiano, M. A1 - Lampitt, R.S. A1 - Danovaro, R. Y1 - 2001/// JF - Progress in Oceanography VL - 50 KW - NORTHEAST ATLANTIC OCEAN KW - DNA KW - MICROORGANISMS KW - PARTICULATE FLUX KW - PARTICLE SINKING SN - 0079-6611 TI - Microbial assemblages associated with sinking particles in the Porcupine Abyssal Plain (NE Atlantic Ocean) SP - 105 AV - none EP - 121 ER - TY - JOUR ID - soton385630 UR - https://eprints.soton.ac.uk/385630/ A1 - Victorero, Lissette A1 - Blamart, Dominique A1 - Pons-Branchu, Edwige A1 - Mavrogordato, Mark N. A1 - Huvenne, Veerle A.I. Y1 - 2016/08/01/ N2 - Cold-water coral mounds, formed through a feed-back process of cold-water coral growth and sediment baffling, have been studied all along the NE Atlantic continental margin. However, major questions remain concerning their formation history, especially their initiation and early development in relation to the surrounding sediment dynamics. For the first time, two small mounds located in a sandy contourite have been cored from the top to mound base: here, the formation history of the Darwin Mounds, located in the Northern Rockall Trough was investigated and reconstructed from two piston cores using a multidisciplinary approach. This consisted of CT-scanning for quantifying coral density changes with depth, grain-size analysis to obtain the hydrodynamic trends and radiocarbon and U-series dating to place the results into a wider paleoceanographic context. The results show that the Darwin Mounds formed during the early Holocene (~ 10 ka BP) through sediment baffling, mainly by Lophelia pertusa. The initiation of both mounds shows a similar pattern of increased current velocities resulting in coarser sediment deposition and a relatively high coral density with a peak of 23 vol%. The mound growth was rapid between ~ 10?9.7 ka BP (up to 277 cm ka? 1 in one of the mounds), with further vibrant growth periods around ~ 8.8 ka BP, 6.5 ka BP and 3.4 ka BP. The demise of the mounds ca. ~ 3 ka BP was likely caused by an intensification in bottom current velocities causing a hostile environment for coral growth in the contourite setting. In a wider context, the development of the Darwin Mounds appears to have responded to the relative strength and position of the Subpolar Gyre, which affected food supply to the corals, sedimentation rates, current speeds and other water mass properties in the area. JF - Marine Geology VL - 378 KW - Lophelia pertusa KW - Cold-water coral mounds KW - North-east Atlantic KW - Darwin Mounds KW - Contourite KW - CT-scan SN - 0025-3227 TI - Reconstruction of the formation history of the Darwin Mounds, N Rockall Trough: How the dynamics of a sandy contourite affected cold-water coral growth SP - 186 AV - public EP - 195 ER - TY - GEN ID - soton429386 UR - https://eprints.soton.ac.uk/429386/ A1 - Vieira, Rui P. A1 - Trueman, Clive N. A1 - Readdy, Lisa A1 - Kenny, Andrew A1 - Pinnegar, John K. Y1 - 2019/02/12/ N2 -

In this paper, we revisit the state of deep-water fisheries to the west of the British Isles and aim to provide an overview on the key drivers behind community changes along continental margins. The deep-water fisheries to the west of the British Isles that extend from the shelf-slope break down to the lower slope and along banks and seamounts of the Rockall Basin, mainly target blue ling Molva dypterygia, roundnose grenadier Coryphaenoides rupestris, orange roughy Hoplostethus atlanticus, with by-catches of black scabbardfish Aphanopus carbo and tusk Brosme brosme. These fishing grounds experienced a long period of exhaustive exploitation until the early 2000s, but subsequently the implementation of management strategies has helped to relieve excessive fishing pressure. It is widely accepted that a better understanding of the long-term implications of disturbance is needed to understand patterns in deep-water communities and what sustainable use and exploitation of resources might look like in this context.

KW - ecosystem disturbance KW - ecosystem management KW - food webs KW - modelling KW - north-east Atlantic Ocean SN - 0022-1112 TI - Deep-water fisheries along the British Isles continental slopes: status, ecosystem effects and future perspectives SP - 1 AV - none EP - 12 ER - TY - RPRT ID - soton19304 UR - https://eprints.soton.ac.uk/19304/ Y1 - 2002/09// PB - International CLIVAR Project Office T3 - No. 25 (Vol. 7(3/4) KW - CLIVAR KW - WCRP KW - Exchanges KW - newsletter KW - Atlantic ED - Villwock, A. ED - Cattle, H. M1 - project_report TI - CLIVAR Exchanges No. 25. Special issue on: CLIVAR Atlantic AV - public EP - 76 ER - TY - JOUR ID - soton426325 UR - https://eprints.soton.ac.uk/426325/ A1 - Vries, Hylke de A1 - Scher, Sebastian A1 - Haarsma, Rein A1 - Drijfhout, Sybren A1 - Delden, Aarnout van Y1 - 2018/10/12/ N2 -

The strong horizontal gradients in sea surface temperature (SST) of the Atlantic Gulf Stream exert a detectable influence on extratropical cyclones propagating across the region. This is shown in a sensitivity experiment where 24 winter storms taken from ERA-Interim are simulated with HARMONIE at 10-km resolution. Each storm is simulated twice. First, using observed SST (REF). In the second simulation a smoothed SST is offered (SMTH), while lateral and upper-level boundary conditions are unmodified. Each storm pair propagates approximately along the same track, however their intensities (as measured by maximal near-surface wind speed or 850-hPa relative vorticity) differ up to ± 25%. A 30-member ensemble created for one of the storms shows that on a single-storm level the response is systematic rather than random. To explain the broad response in storm strength, we show that the SST-adjustment modifies two environmental parameters: surface latent heat flux (LHF) and low-level baroclinicity (B). LHF influences storms by modifying diabatic heating and boundary-layer processes such as vertical mixing. The position of each storm?s track relative to the SST-front is important. South of the SST-front the smoothing leads to lower SST, reduced LHF and storms with generally weaker maximum near-surface winds. North of the SST-front the increased LHF tend to enhance the winds, but the accompanying changes in baroclinicity are not necessarily favourable. Together these mechanisms explain up to 80% of the variability in the near-surface maximal wind speed change. Because the mechanisms are less effective in explaining more dynamics-oriented indicators like 850 hPa relative vorticity, we hypothesise that part of the wind-speed change is related to adjustment of the boundary-layer processes in response to the LHF and B changes.

JF - Climate Dynamics KW - Atlantic winter storms KW - Gulf Stream KW - SST-fronts SN - 0930-7575 TI - How Gulf-Stream SST-fronts influence Atlantic winter storms: results from a downscaling experiment with HARMONIE to the role of modified latent heat fluxes and low-level baroclinicity SP - 1 AV - public EP - 11 ER - TY - JOUR ID - soton187393 UR - https://eprints.soton.ac.uk/187393/ IS - 5 A1 - Våge, Kjetil A1 - Pickart, Robert S. A1 - Sarafanov, Artem A1 - Knutsen, Øyvind A1 - Mercier, Herlé A1 - Lherminier, Pascale A1 - van Aken, Hendrik M. A1 - Meincke, Jens A1 - Quadfasel, Detlef A1 - Bacon, Sheldon Y1 - 2011/05// N2 - In this study 36 hydrographic transects occupied between 1991 and 2007 in the vicinity of the WOCE A1E/AR7E section are used to investigate various aspects of the Irminger Gyre, a narrow cyclonic recirculation in the southwest Irminger Sea. Vertical sections of absolute geostrophic velocity were constructed using satellite and shipboard velocity measurements, and analyzed in conjunction with the hydrographic data and meteorological fields. The Irminger Gyre is a weakly baroclinic feature with a mean transport of 6.8±1.9 Sv (View the MathML source). At mid-depth it contains water with the same properties as Labrador Sea Water (LSW). During the 17-year study period large changes occurred in the gyre and also within the boundary flow encircling the Irminger Sea. The gyre intensified and became more stratified, while the upper-layer circulation of the boundary current system weakened. The latter is consistent with the overall decline of the North Atlantic subpolar gyre reported earlier. However, the decline of the upper-ocean boundary currents was accompanied by an intensification of the circulation at deeper levels. The deep component of both the northward-flowing boundary current (the Irminger Current) and the southward-flowing boundary current (the Deep Western Boundary Current) strengthened. The increase in transport of the deep Irminger Current is due to the emergence of a second deep limb of the current, presumably due to a shift in pathways of the branches of the subpolar gyre. Using a volumetric water mass analysis it is argued that LSW was formed locally within the Irminger Gyre via deep convection in the early 1990s. In contrast, LSW appeared outside of the gyre in the eastern part of the Irminger Sea with a time lag of 2?3 years, consistent with transit from the Labrador Sea. Thus, our analysis clarifies the relative contributions of locally-versus remotely-formed LSW in the Irminger Sea. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 58 KW - Irminger Sea KW - Labrador Sea Water KW - Deep Western Boundary Current KW - Irminger Current KW - North Atlantic KW - Deep convection SN - 0967-0637 TI - The Irminger Gyre: Circulation, convection, and interannual variability SP - 590 AV - none EP - 614 ER - TY - JOUR ID - soton453239 UR - https://eprints.soton.ac.uk/453239/ A1 - Wang, Ruixue A1 - Clegg, Josephine A. A1 - Scott, Peter M. A1 - Larkin, Christina S. A1 - Deng, Feifei A1 - Thomas, Alexander L. A1 - Zheng, Xin-yuan A1 - Piotrowski, Alexander M. Y1 - 2021/12/01/ N2 -

Significant gaps in our understanding of the oceanic cycling of neodymium (Nd) and the other rare earth elements (REEs) remain despite decades of research. One important observation which has not been adequately explained is that the concentration of dissolved Nd typically increases with depth, similar to nutrient profiles, while Nd isotopes appear to reflect conservative water mass mixing in the intermediate and deep ocean; this has been termed the ?Nd paradox?. Here we present a detailed study of the dissolved Nd isotopic composition across a section at 40°S in the South Atlantic, collected by UK GEOTRACES cruise (section GA10). The South Atlantic represents a natural laboratory for our understanding of spatial controls on ocean geochemistry, because of the large variability of inputs, spatial differences in particulate cycling, and horizontal advection and mixing at depth between major northern- and southern-sourced water masses. This variability has also made the South Atlantic a critical region subject to intense investigations that aim at reconstructing past changes in ocean processes, such as changes in biological productivity and deep ocean circulation. Our Nd isotope results from the GA10 section provide observational data show the signal of water mass mixing and reversible scavenging. In the surface ocean (0?600 m), Nd isotopic compositions are distinct between different surface ocean currents and spatially can be tied to various continental sources. In the intermediate ocean (600?2500 m), the vertical Nd isotope distribution exhibits distinct signals of different water masses by horizontal advection, including upper North Atlantic Deep Water and Antarctic Intermediate Water formed in the Atlantic Ocean or the Indian Ocean. The Nd isotope distribution also reflects influence of reversible scavenging that smears the signals downwards in the water column (i.e., offset to more radiogenic values). In the deep ocean below 2500 m, Nd isotope distribution largely follows conservative water mass mixing model. Nd concentration in the deep ocean, however, deviates from conservative mixing and increases constantly with depth. We also observe that Nd isotopes appear to be shifted towards the composition of overlying water masses. These observations suggest that reversible scavenging of Nd onto organic and other types of particles is a major vertical process throughout the water column. We also suggest that this process can resolve the ?Nd paradox? of decoupling of Nd concentration and isotopic composition due to mixing dynamics. Because abyssal water masses already have a high Nd concentration, a given amount of Nd added from the vertical process has less of an effect on Nd isotopic compositions in deep water masses than it does for intermediate water masses which have comparatively low Nd concentration.

JF - Geochimica et Cosmochimica Acta VL - 314 KW - GEOTRACES KW - Nd paradox KW - Neodymium cycling KW - Neodymium isotopes KW - South Atlantic SN - 0016-7037 TI - Reversible scavenging and advection ? resolving the neodymium paradox in the South Atlantic SP - 121 AV - public EP - 139 ER - TY - JOUR ID - soton444405 UR - https://eprints.soton.ac.uk/444405/ IS - 9 A1 - Wang, Shunguo A1 - Constable, Steven A1 - Rychert, Catherine A1 - Harmon, Nicholas Y1 - 2020/09/01/ N2 -

The differential motion between the lithosphere and the asthenosphere is aseismic, so the magnetotelluric (MT) method plays an important role in studying the depth and nature of the lithosphere-asthenosphere boundary (LAB). In March 2016, we deployed 39 marine MT instruments across the Middle Atlantic Ridge (MAR), 2,000 km away from the African coast, to study the evolution of the LAB with ages out to 45 million years (My). The MT acquisition time was limited to about 60 days by battery life. After analyzing dimensionality and coast effects for the MT data, determinant data were inverted for two-dimensional resistivity models along two profiles north and south of the Chain Fracture Zone (CFZ). The imaged thickness of the lithospheric lid (>100 ?m) ranges from 20 to 80 km, generally thickening with age. In the north of CFZ, punctuated low-resistivity anomalies (<1 ?m), likely associated with potential partial melts, occur along its base. In the south of CFZ, the base of the resistive lid is demarcated by a low-resistivity channel (<1 ?m) most likely fed by deeper melts. Sensitivity analyses and structural recovery tests indicate the robustness of these features. Resistivity models are in good agreement with results of seismic data. These results imply that partial melt is persistent over geologic timescales and that the LAB is dynamic features fed by upward percolation of mantle melt. The melt fraction is about 1?7% based on the resistivity, temperature, pressure, and hydrous basalt models, which is consistent with petrophysical observations.

JF - Geochemistry, Geophysics, Geosystems VL - 21 KW - Middle Atlantic Ridge KW - determinant inversion KW - lithosphere-asthenophere boundary KW - magnetotelluric method KW - marine electromagnetics KW - partial melts SN - 1525-2027 TI - A Lithosphere?Asthenosphere boundary and partial melt estimated Using marine magnetotelluric data at the central middle Atlantic Ridge AV - public ER - TY - JOUR N1 - Funding Information: This cruise was funded by the NERC-funded ZIPLOc project (NE/N001125/1). WW?s PhD studentship was funded by the Chinese Scholarship Council and the Graduate School of the National Oceanography Centre Southampton; KK?s PhD studentship was funded by the Graduate School of the National Oceanography Centre Southampton. Acknowledgments Publisher Copyright: Copyright © 2023 Wang, Goring-Harford, Kunde, Woodward, Lohan, Connelly and James. ID - soton477886 UR - https://eprints.soton.ac.uk/477886/ A1 - Wang, Wenhao A1 - Goring-Harford, Heather A1 - Kunde, Korinna Gerda Lydia A1 - Woodward, E.M.S. A1 - Lohan, Maeve A1 - Connelly, D.P. A1 - James, Rachael Y1 - 2023/05/26/ N2 -

Chromium (Cr) is a redox-sensitive element and because Cr isotopes are fractionated by redox and/or biological processes, the Cr isotopic composition of ancient marine sediments may be used to infer changes in past seawater oxygenation or biological productivity. While there appears to be a ?global correlation? between the dissolved Cr concentration and Cr isotopic composition of seawater, there is ongoing debate about the relative importance of external sources and internal cycling on shaping the distribution of dissolved Cr that needs to be resolved to validate the efficacy of using Cr isotopes as a paleo proxy. Here, we present full water column depth profiles of total dissolved Cr (Cr(VI)+Cr(III)) and dissolved Cr isotopes (? 53Cr), together with ancillary data, for three stations along a transect (GEOTRACES GApr08) across the sub-tropical North Atlantic. Concentrations of dissolved Cr ranged between 1.84 and 2.63 nmol kg -1, and ? 53Cr values varied from 1.06 to 1.42?. Although atmospheric dust, hydrothermal vents and seabed sediments have the potential to modify the distribution of Cr in the oceans, based on our observations, there is no clear evidence for substantial input of Cr from these sources in our study region although benthic inputs of Cr may be locally important in the vicinity of hydrothermal vents. Subsurface waters (below the surface mixed layer to 700 m water depth) were very slightly depleted in Cr (by up to ~0.4 nmol kg -1), and very slightly enriched in heavy Cr isotopes (by up to ~0.14?), relative to deeper waters and the lowest Cr concentrations and highest ? 53Cr values coincided with lowest concentrations of colloidal (0.02 to 0.2 ?m size fraction) Fe. We found no direct evidence for biological uptake of dissolved Cr in the oligotrophic euphotic zone or removal of Cr in modestly oxygen depleted waters (O 2 concentrations ~130 ?mol kg -1). Rather, we suggest removal of Cr (probably in the form of Cr(III)) in subsurface waters is associated with the formation of colloid aggregates of Fe-(oxyhydr)oxides. This process is likely enhanced by the high lithogenic particle load in this region, and represents a previously unrecognized export flux of Cr. Regeneration of Cr in deeper waters leads to subtly increased levels of Cr alongside decreased ? 53Cr values at individual sites, but this trend is more obvious at the global scale, with ? 53Cr values decreasing with increasing radiocarbon age of deep waters, from 1.16 ± 0.10? (1SD, n=11) in deep Atlantic waters to 0.77 ± 0.10? (1SD, n=25) in deep Pacific waters. Removal of relatively isotopically light Cr from subsurface waters onto particulate material and regeneration of this Cr back into the dissolved phase in deep waters partly accounts for the systematic relationship between ? 53Cr and Cr concentrations in seawater discussed by other studies.

JF - Frontiers in Marine Science VL - 10 KW - GEOTRACES KW - North Atlantic Ocean KW - chromium isotopes KW - particle scavenging KW - regeneration SN - 2296-7745 TI - Biogeochemical cycling of chromium and chromium isotopes in the sub-tropical North Atlantic Ocean AV - public EP - 18 ER - TY - JOUR ID - soton2250 UR - https://eprints.soton.ac.uk/2250/ IS - 1-2 A1 - Waniek, J.J. Y1 - 2003/// N2 - In this paper, the relationship between changes in the intensity of the spring bloom and changes in the physical forcing, mediated by the upper ocean mixing, is examined and illustrated. An idealized mixed-layer model coupled with an NPZD model with two different detritus compartments provides a conceptual framework, predicting the biological response to vertical mixing anomalies in the ocean?surface boundary layer. The model of coupled biological?hydrodynamic processes is used to search for general physical principles of phytoplankton bloom regulation in open ocean waters. The study addresses three questions: How does an individual winter differ from climatologically averaged ones? What are the dynamics of stratification in open ocean systems as influenced by variable atmospheric forcing? How does phytoplankton growth respond to these dynamics?
The calculations suggest that changes in the balance of the atmospheric forcing on a daily scale could lead to less pronounced fluctuations of the mixed layer in winter as during most of the day the heat input by the sun exceeds or compensates the heat loss by nonsolar heat flux components (i.e. transient or moderate conditions). Furthermore, the model results show that the springtime shallowing of the mixed layer is not typically a smooth transition, but is interrupted by mixing events stimulated by passage of weather systems. The frequency and intensity of these synoptic events varies from year to year due to shift in storm tracks and modes of atmospheric circulation. The simulations suggest that such synoptic events (storms) associated with time scales of several days, and the period of the year when the heat flux changes sign, are important for the development of the phytoplankton population. Enhanced or reduced storm frequency associated with changes in vertical mixing intensity during the late winter/spring period leads to an increase/decrease in amplitude and duration of the bloom caused by enhanced/reduced nutrient supply or retard it due to light limitation. Finally, supported by the model results and observations, the role of interannual variability in physical forcing on timing, amplitude and structure of the phytoplankton bloom for the period 1989?1997 is examined. JF - Journal of Marine Systems VL - 39 KW - BIOGEOCHEMICAL CYCLE KW - ATLANTIC OCEAN KW - PHYTOPLANKTON KW - BIOMASS KW - BIOLOGY SN - 0924-7963 TI - The role of physical forcing in initiation of spring blooms in the northeast Atlantic SP - 57 AV - none EP - 82 ER - TY - JOUR ID - soton15838 UR - https://eprints.soton.ac.uk/15838/ IS - 1 A1 - Waniek, J.J. A1 - Schulz-Bull, D.E. A1 - Blanz, T. A1 - Prien, R. A1 - Oschlies, A. A1 - Muller, T. Y1 - 2005/01// N2 - Results of particle flux studies using sediment traps in the northeast Atlantic Ocean at 33oN, 22oW, a time-series station (L1/K276) operated within the German contribution to the international Joint Global Ocean Flux Study (JGOFS) between summer 1993 and summer 2001, are presented. The particle flux at 2000 m depth is highly seasonal with only one main peak in February and March and is characterized by strong interannual variability. The comparison of the particle flux time series with the measurements of chlorophyll and phaeopigments in the sediment trap material, and chlorophyll-a concentrations at surface from SeaWiFS together with the similarity of the pattern observed in the alkenone flux, particulate organic carbon (POC) and calcium carbonate (CaCO3) leads to the conclusion that the particle flux at this position is fast and directly coupled to the phytoplankton development and decay in the overlying euphotic zone. SeaWiFS chlorophyll-a data (1997?2001) and characteristics of the upper water column (mixed layer depth, depth of nitracline, primary production) as predicted by an eddy-permitting model of the North Atlantic coupled with a simple nitrate?phytoplankton?zooplankton?detritus (NPZD) pelagic-ecosystem model are used to understand the observed interannual differences in particle flux at 2000 m. Our results suggest that the interannual differences in the observed particle flux are a direct consequence of the variability of phytoplankton biomass and primary production in the euphotic zone in this region. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 52 KW - Northeast Atlantic KW - 33N KW - 22W KW - particle flux KW - current observation KW - primary production KW - sediment traps KW - interannual variability TI - Interannual variability of deep water particle flux in relation to production and lateral sources in the northeast Atlantic SP - 33 AV - none EP - 50 ER - TY - JOUR ID - soton20411 UR - https://eprints.soton.ac.uk/20411/ IS - 3-4 A1 - Waniek, J.J. A1 - Schulz-Bull, D.E. A1 - Kuss, J. A1 - Blanz, T. Y1 - 2005/// N2 - Long-term observations of the deep ocean particle flux from three sites in the northeast Atlantic (33°N, 22°W; 47°N, 20°W; 54°N, 20°W) provide the basis for comparison and characterization of the biogeochemical provinces in terms of sedimentation pattern. Deep ocean particle flux data (2000 m) for fluxes of total mass and the flux composition are presented and compared to published sediment trap data from this area to consider regional-scale variations in the quantity and composition of settling material. The observations show that in the northeast Atlantic gradient of decreasing mass flux from North to South, exists consistent with known changes of biological productivity in surface waters. This gradient is associated with similar trends in opal and particulate organic carbon, whereas calcium carbonate shows trend in the opposite direction. The changes in the composition of the settling material found along the transect are indicating that the calcium carbonate flux is critical in removing organic matter from the upper ocean to the deeper sink. Its role declines from the subtropical ocean (60?80% of the particle flux) towards North (< 40%) reflecting the decreasing importance of coccolithophorid/foraminiferal blooms for particle flux from the subtropical to the subpolar North Atlantic. In contrast, the role of biogenic silica (opal) in regard to the ballasting effect increases towards North. The northern sites have much higher percentage of biogenic silica than the sites in the South, because of the deep winter mixing and the seasonality of phytoplankton dominated by diatom blooms during spring and summer. The comparison of the seasonal pattern of particle flux with the seasonal pattern of surface chlorophyll a concentrations from SeaWiFS together with the similarity of the pattern observed in calcium carbonate and opal leads to the conclusion that the particle flux at two positions (33°N, 22°W; 47°N, 20°W) is fast and directly coupled to the phytoplankton dynamics in the overlying euphotic zone. JF - Journal of Marine Systems VL - 56 KW - Northeast Atlantic KW - biogeochemical provinces KW - particle flux KW - catchment areas KW - current observation KW - sediment traps KW - regional and interannual variability SN - 0924-7963 TI - Long time series of deep water particle flux in three biogeochemical provinces of the northeast Atlantic SP - 391 AV - none EP - 415 ER - TY - JOUR ID - soton15189 UR - http://www.int-res.com/articles/meps2005/288/m288p045.pdf A1 - Waniek, Joanna J. A1 - Holliday, N.P. A1 - Davidson, R. A1 - Brown, L. A1 - Henson, S.A. Y1 - 2005/// N2 - The relationship between physical properties of the water column and spatial patchiness of phytoplankton spring bloom development on the Greenland shelf edge and in the Irminger Sea was investigated using data collected during a spring cruise (April and May 2002). The observations confirm a strong relationship between the onset and stage of bloom development and the stratification induced by freshwater input to the surface layer in the shelf region. Interestingly, at the shelf, in the region influenced by melting of the seasonal ice-cover, the vertical distribution of chlorophyll a showed a subsurface maximum at ca. 25 m depth at several stations. Since nutrients were not exhausted at these stations, such a pattern does not conform to the general picture of a spring bloom. In contrast, in the open ocean part of the Irminger Sea pre-bloom conditions and a retarded development of the phytoplankton population were observed with low, more uniform distribution of chlorophyll a. The nitrate drawdown was estimated at between 16.5 and 270 µm m?2 (mean 108.6 ± 82.2 µm m?2) and the new primary production was estimated to be between 1.3 and 21.4 g C m?2 (8.6 ± 6.5 g C m?2), corresponding to 0.42 g C m?2 d?1. The phytoplankton community in the melting ice zone consisted of Phaeocystis sp., small flagellates (< 4 µm) and picoplankton, while diatoms were less abundant. Phaeocystis sp. contributed up to 15 g C m?2 to the carbon biomass (70% of total carbon measured), whereas the contribution of diatoms and flagellates to carbon biomass was relatively low, with up to 1.2 g C m?2 (5.7%) and up to 2.5 g C m?2 (11.7%), respectively. On the shelf the bloom starts at the very beginning of stabilisation (elevated N2 values) which results solely from the release of meltwater. The locally restricted water stability leads to a patchy phytoplankton distribution in the Irminger Sea. JF - Marine Ecology Progress Series VL - 288 KW - hydrography KW - Brunt-Vaisala frequency KW - stratification KW - phytoplankton KW - plankton blooms KW - North Atlantic KW - Irminger Sea KW - East Greenland shelf SN - 0171-8630 TI - Freshwater control of onset and species composition of Greenland shelf spring bloom SP - 45 AV - none EP - 57 ER - TY - RPRT ID - soton50050 UR - https://eprints.soton.ac.uk/50050/ A1 - Weaver, P.P.E. A1 - Masson, D.G. Y1 - 2007/12// N2 - The major objective of RRS James Cook Cruise 10 was to increase our understanding of how seafloor environmental variables affect the biodiversity, structure, function and dynamics of faunal communities in two specific ?biological hotspot? environments, mud volcanoes and submarine canyons, on the NE Atlantic continental slope. The cruise was jointly supported by OCEANS 2025 (Theme 5) and the EU Hotspot Environmental Research on the Margins of European Seas (HERMES) Project. The work was based mainly on the use of the Remotely Operated Vehicle (ROV) ISIS, but a wide suite of additional techniques including sediment coring, water column measurement and sampling, benthic trawling and swath mapping were also deployed. Forty-one ROV dives, some lasting for up to 36 hours, were completed during a highly successful cruise. The ROV programme included swath mapping, video and still photography, sediment coring using both push and mini-box corers, rock sampling, collection of biological samples, water sampling, subseafloor temperature measurement, and the placing and manipulating of a variety of seafloor experiments. PB - National Oceanography Centre T3 - 22 KW - Biscay Bay KW - Cadiz Gulf KW - cruise 10 2007 KW - ISIS KW - HERMES KW - James Cook KW - mud volcanoes KW - Nazare Canyon KW - NE Atlantic KW - OCEANS 2025 KW - ROV KW - Setubal Canyon KW - submarine canyon KW - Whittard Canyon M1 - project_report TI - RRS James Cook Cruise 10, 13 May-07 Jul 2007. Hotspot ecosystems in the NE Atlantic, UK contribution to the HERMES Project. Mud volcanoes in the Gulf of Cadiz; submarine canyons west of Portugal; submarine canyons in the northern Bay of Biscay AV - public EP - 94 ER - TY - JOUR ID - soton8776 UR - https://eprints.soton.ac.uk/8776/ IS - s1 A1 - Weaver, Philip P.E. A1 - Wynn, Russell B. A1 - Kenyon, Neil H. A1 - Evans, Jeremy Y1 - 2000/// N2 - The north-east Atlantic continental margin displays a wide range of sediment transport systems with both along-slope and down-slope processes. Off most of the north-west African margin, south of 26°N, upwelling produces elevated accumulation rates, although there is little fluvial input. This area is subject to infrequent but large-scale mass movements, giving rise to debris flows and turbidity currents. The turbidity currents traverse the slope and deposit thick layers on the abyssal plains, while debris flows deposit on the continental slope and rise. From the Atlas Mountains northwards to 56°N, the margin is less prone to mass movements, but is cut by a large number of canyons, which also funnel turbidity currents to the abyssal plains. The presence of a lithospheric plate boundary off SW Iberia is believed to have led to high rates of sediment transport to the deep sea. Even larger quantities of coarse sediments have fed the canyons and abyssal plains in the Bay of Biscay as a result of drainage from melting icecaps. Bottom currents have built sediment waves off the African and Iberian margins, and created erosional furrows south of the Canaries. The Mediterranean outflow is a particularly strong bottom current near the Straits of Gibraltar, depositing sand waves and mud waves in the Gulf of Cadiz. North of 56°N, the margin is heavily influenced by glacial and glaciomarine processes active during glacial times, which built glacial trough-mouth fans, such as the North Sea Fan, and left iceberg scour marks on the upper slope and shelf. Over a long period, especially during interglacials, this part of the margin has been greatly affected by along-slope currents, with less effect by turbidity currents than on the lower latitude margins. Large-scale mass movements are again a prominent feature, particularly off Norway and the Faeroes. Some of these mass movements have occurred during the Holocene, although high glacial sedimentation rates may have contributed to the instability. JF - Sedimentology VL - 47 KW - continental margins KW - sedimentation KW - northeast atlantic ocean KW - sediment transport SN - 0037-0746 TI - Continental margin sedimentation, with special reference to the north-east Atlantic margin SP - 239 AV - none EP - 256 ER - TY - JOUR ID - soton188141 UR - https://eprints.soton.ac.uk/188141/ IS - 1 A1 - Weber, L.I. A1 - Hawkins, S.J. N2 - Patella vulgata is a boreal cold temperate species and is the dominant limpet in northern Europe. Few works have focussed on the population genetics of this species. Therefore, the aim of this work was to assess the degree of genetic and morphological differentiation of P. vulgata on a macroscale by using 20 allozyme loci and 6 morphological variables. Samples were taken from the following locations: Dingle Peninsula (Southwest Ireland), Port Erin (Southwest Isle of Man), St. Bees Head (north Cumbria, England), St. Agnes Head (north Cornwall, England), Cellar Beach (south Devon, England), Whitley Bay (north Newcastle-Upon-Tyne, England), Sines (Portugal), and Pointe de Chanchardon, La Rochelle (Bay of Biscay, France). Morphological variables were analysed by the multivariate Canonical discriminant analysis. Genetic variation was assessed by diversity measures such as polymorphism and heterozygosity; genetic subdivision of P. vulgata population was determined by the estimator ? of F ST, and the genetic similarity between populations was measured by Nei?s genetic identity. No significant morphological differentiation was observed among samples. Moderate genetic population subdivision was observed (? = 0.137±0.074) despite great geographic distances. The minimum genetic identity observed was between Ireland and France (I = 0.942) and maximum was observed between Portugal and north-east England (I=0.998). Two main groups were shown by UPGMA cluster analysis (I = 0.965). One formed by Irish, Manx, north Cumbria, and curiously, south Devon samples, while the second includes Portuguese, French, north-Newcastle-upon-thyne, and north Cornwall samples. No association (g = 0.956; p>0.050) was found between pair-wise genetic divergence and geographic distance separating subpopulations, mainly due to an unexpected pattern of genetic heterogeneity found in Southwest England. VL - 553 TI - Allozymic Differentiation Among Geographically Distant Populations of Patella vulgata (Mollusca, Patellogastropoda) AV - none EP - 275 N1 - Published article bears erroneous author listing: L.I. Weber and L.I. Hawkins Y1 - 2006/// JF - Hydrobiologia KW - allozymes KW - Gastropoda KW - north-east Atlantic KW - Patella vulgata KW - population genetics SN - 0018-8158 SP - 267 ER - TY - JOUR ID - soton1402 UR - http://www.agu.org/pubs/crossref/2003/2000JC000762.shtml IS - C10 A1 - Weiss, D. A1 - Boyle, E.A. A1 - Wu, J. A1 - Chavagnac, V. A1 - Michel, A. A1 - Reuer, M.K. Y1 - 2003/// N2 - Lead concentrations and isotope ratios were measured in North Atlantic surface water samples collected in 1981 (29°?79°N, 6°E?49°W) and in 1989 (23°?39°N, 29°?68°W). In the early 1980s, 206Pb/207Pb ratios in the North African Basin averaged 1.193 ± 0.005 (1? ). Similar radiogenic ratios within the level of analytical precision (average 0.29%) were found in the Labrador and Iceland Basins (1.198 ± 0.006) and in the Norwegian Sea (1.196 ± 0.008). These radiogenic mixed layer signatures along with atmospheric global lead emission patterns suggest that most North Atlantic lead in the early 1980s was derived from North American leaded gasoline. Samples in the East Iberian Basin near Portugal and France showed lower 206Pb/207Pb ratios, between 1.167 and 1.182, indicating a significant influence of less radiogenic atmospheric lead transported from Europe and possibly the influence of the Rio Tinto acid mine drainage very close to shore in the Gulf of Cadiz. [Pb] across the entire North Atlantic Basin ranged between 54 and 145 pmol/kg, with the lowest values (54?74 pmol/kg) found at high latitudes (>65°N). In the late 1980s, surface waters in the western subtropical North Atlantic (North American Basin/Sargasso Sea, >47°W) and in the eastern subtropical North Atlantic (North African Basin/Central Iberian Basin, <45°W) showed very similar 206Pb/207Pb signatures with little zonal variation, ranging from 1.177 to 1.192. Lead concentrations ranged between 47 and 137 pmol/kg, increasing slightly from west to east. South of 25°N in the equatorial North Atlantic, crossing the subtropical/tropical surface water boundary, the 206Pb/207Pb seawater signatures were significantly less radiogenic (1.170?1.175) and concentrations were lower (51 pmol/kg). This difference suggests a relative increase in the atmospheric lead supply from the western Mediterranean/North African continent via Trade Easterlies and illustrates the effective barrier between the subtropical/tropical surface water exchanges. Triple-isotope plots (206Pb, 207Pb, and 208Pb) suggest that most of the lead can be accounted for by wet aerosol deposition derived from the adjacent landmasses of America to the west (transported via the North American Westerlies) and from Europe to the east (transported via the European Easterlies) and probably by some advected surface waters from the Sargasso Sea. The 1989 triple-isotope plot suggests, however, a third lead source in the subtropical western North Atlantic, possibly leaded gasoline from Mexico. Gasoline lead emission patterns as well as atmospheric lead isotope signatures confirm that gasoline was the main pollutant source in the early 1980s but suggest that contributions from high-temperature industrial processes (coal combustion, steel manufacture, waste incineration) have been increasing in the late 1980s. From isotopic mass balance estimates, lead inputs to the 1980s North Atlantic were dominated by North American sources (>53%). These elemental and isotopic results demonstrate the strongly variable isotopic and elemental signatures of North American and European lead throughout the North Atlantic Ocean, frequently dominated by high 206Pb/207Pb and [Pb] North American signatures throughout the subtropical North Atlantic gyre.
JF - Journal of Geophysical Research VL - 108 KW - GEOLOGY KW - surface circulation KW - North Atlantic KW - Pb isotopes and concentrations KW - atmospheric deposition KW - pollution. SN - 0148-0227 TI - Spatial and temporal evolution of lead isotope ratios in the North Atlantic Ocean between 1981 and 1989 AV - none ER - TY - JOUR ID - soton419070 UR - https://eprints.soton.ac.uk/419070/ IS - 1 A1 - Westerhold, T. A1 - Röhl, U. A1 - Donner, B. A1 - Frederichs, T. A1 - Kordesch, W.E.C. A1 - Bohaty, S.M. A1 - Hodell, D.A. A1 - Laskar, J. A1 - Zeebe, R.E. Y1 - 2018/01// N2 -

Recognizing and deciphering transient global warming events triggered by massive release of carbon into Earth's ocean-atmosphere climate system in the past are important for understanding climate under elevated pCO2 conditions. Here we present new high-resolution geochemical records including benthic foraminiferal stable isotope data with clear evidence of a short-lived (30 kyr) warming event at 41.52 Ma. The event occurs in the late Lutetian within magnetochron C19r and is characterized by a ?2°C warming of the deep ocean in the southern South Atlantic. The magnitudes of the carbon and oxygen isotope excursions of the Late Lutetian Thermal Maximum are comparable to the H2 event (53.6 Ma) suggesting a similar response of the climate system to carbon cycle perturbations even in an already relatively cooler climate several million years after the Early Eocene Climate Optimum. Coincidence of the event with exceptionally high insolation values in the Northern Hemisphere at 41.52 Ma might indicate that Earth's climate system has a thermal threshold. When this tipping point is crossed, rapid positive feedback mechanisms potentially trigger transient global warming. The orbital configuration in this case could have caused prolonged warm and dry season leading to a massive release of terrestrial carbon into the ocean-atmosphere system initiating environmental change.

JF - Geochemistry, Geophysics, Geosystems VL - 19 KW - 2°C warming of the deep ocean in the southern South Atlantic KW - Eocene transient (30 kyr) warming event at 41.52 Ma KW - Late Lutetian Thermal Maximum (LLTM) occurs within magnetochron C19r KW - LLTM coincidences with exceptionally high insolation KW - potential thermal threshold of Earth's climate system SN - 1525-2027 TI - Late Lutetian thermal maximum?crossing a thermal threshold in Earth's climate system? SP - 73 AV - public EP - 82 ER - TY - JOUR ID - soton181863 UR - https://eprints.soton.ac.uk/181863/ IS - 1-2 A1 - Wheeler, A.J. A1 - Kozachenko, M. A1 - Henry, L.-A. A1 - Foubert, A. A1 - de Haas, H. A1 - Huvenne, V.A.I. A1 - Masson, D.G. A1 - Olu, K. Y1 - 2011/03/30/ N2 - This paper presents a comprehensive overview of the Moira Mounds in the Porcupine Seabight, combining a review of currently published material with new data and interpretations. The Moira Mounds are circular to ovoid-shaped individual or clustered coral banks (referred to as ?scleractinian spaced cluster macroreefs?) located in the Belgica (carbonate) mound province, Porcupine Seabight, west of Ireland. They are up to 10 m high and 20 to 35 m in diameter. For the first time, a map showing the complete extent and location of the Moira Mounds is published, revealing 256 examples grouped into four areas mainly between 800 and 1100 m water depth. ROV groundtruthing revealed the importance of bedload sand transport in Moira Mound formation and development processes through sediment entrapment by coral frameworks (Lophelia pertusa and Madrepora oculata). New estimated growth rates for the Moira Mounds are comparable to those measured for much larger Irish coral carbonate mounds but an order of magnitude lower than rates from comparably sized reefs offshore Norway. As well as the framework corals, 26 macrobenthic invertebrate species were identified from a single box core that were similar to those communities found in adjacent off-mound habitats. It is proposed that the Moira Mounds are an example of the early stage growth phase of nearby giant coral carbonate mounds and represent a westward extension of the zone of active cold-water coral mound growth and therefore a deepening of the zone of cold-water coral growth over recent climate cycles. JF - Marine Geology VL - 282 KW - cold-water coral KW - coral carbonate mound KW - benthic processes KW - biogeological processes KW - marine geology KW - NE Atlantic SN - 0025-3227 TI - The Moira Mounds, small cold-water coral banks in the Porcupine Seabight, NE Atlantic: Part A?an early stage growth phase for future coral carbonate mounds? SP - 53 AV - none EP - 64 ER - TY - JOUR ID - soton359132 UR - https://eprints.soton.ac.uk/359132/ IS - 10 A1 - Wheeler, A.J. A1 - Murton, B.J. A1 - Copley, J. A1 - Lim, A. A1 - Carlsson, J. A1 - Collins, P. A1 - Dorschel, B. A1 - Green, D. A1 - Judge, M. A1 - Nye, V. A1 - Benzie, J. A1 - Antoniacomi, A. A1 - Coughlan, M. A1 - Morris, K. Y1 - 2013/10// N2 - Geological, biological, morphological, and hydrochemical data are presented for the newly discovered Moytirra vent field at 45oN. This is the only high temperature hydrothermal vent known between the Azores and Iceland, in the North Atlantic and is located on a slow to ultraslow-spreading mid-ocean ridge uniquely situated on the 300 m high fault scarp of the eastern axial wall, 3.5 km from the axial volcanic ridge crest. Furthermore, the Moytirra vent field is, unusually for tectonically controlled hydrothermal vents systems, basalt hosted and perched midway up on the median valley wall and presumably heated by an off-axis magma chamber. The Moytirra vent field consists of an alignment of four sites of venting, three actively emitting ?black smoke,? producing a complex of chimneys and beehive diffusers. The largest chimney is 18 m tall and vigorously venting. The vent fauna described here are the only ones documented for the North Atlantic (Azores to Reykjanes Ridge) and significantly expands our knowledge of North Atlantic biodiversity. The surfaces of the vent chimneys are occupied by aggregations of gastropods (Peltospira sp.) and populations of alvinocaridid shrimp (Mirocaris sp. with Rimicaris sp. also present). Other fauna present include bythograeid crabs (Segonzacia sp.) and zoarcid fish (Pachycara sp.), but bathymodiolin mussels and actinostolid anemones were not observed in the vent field. The discovery of the Moytirra vent field therefore expands the known latitudinal distributions of several vent-endemic genera in the north Atlantic, and reveals faunal affinities with vents south of the Azores rather than north of Iceland. JF - Geochemistry, Geophysics, Geosystems VL - 14 KW - Mid-Atlantic Ridge KW - hydrothermal vent KW - massive sulfides KW - vent biota KW - median valley fault SN - 1525-2027 TI - Moytirra: discovery of the first known deep-sea hydrothermal vent field on the slow-spreading Mid-Atlantic Ridge north of the Azores SP - 4170 AV - public EP - 4184 ER - TY - JOUR ID - soton354768 UR - https://eprints.soton.ac.uk/354768/ IS - 1-4 A1 - Whiteside, Jessica H. A1 - Olsen, Paul E. A1 - Eglinton, Timothy I. A1 - Cornet, Bruce A1 - McDonald, Nicholas G. A1 - Huber, Philip Y1 - 2011/02/11/ N2 - Triassic and Early Jurassic age lacustrine deposits of eastern North American rift basins preserve a spectacular record of precession-related Milankovitch forcing in the Pangean tropics in the wake of the end-Triassic extinction event (ETE). The abundant and well-preserved fossil fish assemblages from these great lakes show cyclical changes that track the permeating hierarchy of climatic cycles. To detail ecosystem processes correlating with succession of fish communities, bulk ?13C was measured through a 100 ky series of precession-forced lake level cycles in the lower Shuttle Meadow Formation of the Hartford rift basin, Connecticut, that were deposited within 50 ky after the ETE. The deep-water phase of one of these cycles, the Bluff Head Bed, has produced thousands of articulated fish. There are fluctuations in the bulk ?13Corg in the cyclical strata that reflect differing degrees of lake water stratification, nutrient levels, and relative proportion of algal vs. plant derived organic matter that trace fish community changes. Extrinsic changes in the global exchangeable reservoirs can be excluded as an origin of this variability because compound-specific ?13C of n-alkanes from plant leaf waxes in the same strata show no such variability. Although higher taxonomic levels of the fish communities responded largely by sorting of taxa by environmental forcing, at the species level the holostean genus Semionotus responded by in situ evolution, and ultimately extinction, of a species flock. Fluctuations at the higher frequency, climatic precessional scale are mirrored at lower frequency, eccentricity modulated scales, all following the lake-level hierarchical pattern. Thus, changes in lacustrine isotopic ratios amplify the Milankovitch climate signal that was already intensified by sequelae of the end-Triassic extinctions. The degree to which the ecological structure of modern lakes responds to similar environmental cyclicity is largely unknown, but similar patterns and processes are present within the Neogene history of the East African great lakes. JF - Palaeogeography Palaeoclimatology Palaeoecology VL - 301 KW - central atlantic magmatic province KW - end-triassic extinction KW - paleolimnology KW - species flocks KW - carbon isotopes KW - semionotidae KW - redfieldiidae SN - 0031-0182 TI - Pangean great lake paleoecology on the cusp of the end-Triassic extinction SP - 1 AV - none EP - 17 ER - TY - JOUR ID - soton354772 UR - https://eprints.soton.ac.uk/354772/ IS - 1-4 A1 - Whiteside, Jessica H. A1 - Olsen, Paul E. A1 - Kent, Dennis V. A1 - Fowell, Sarah J. A1 - Et-Touhami, Mohammed Y1 - 2007/02/09/ N2 - We present new data and a synthesis of cyclostratigraphic, lithostratigraphic, biostratigraphic, and published magnetostratigraphic and basalt geochemical data from eastern North America and Morocco in an attempt to clarify the temporal relationship between the Triassic?Jurassic mass extinction (? 202 Ma) and Earth's largest sequence of continental flood basalts, the Central Atlantic magmatic province (CAMP). Newly discovered zones of reverse polarity within CAMP flow sequences of Morocco have been hypothesized by Marzoli et al. [Marzoli, A., Bertrand, H., Knight, K.B., Cirilli, S., Buratti, N., Vérati, C., Nomade, S., Renne, P.R., Youbi, N., Martini, R., Allenbach, K., Neuwerth, R., Rapaille, C., Zaninetti, L., Bellieni, G., 2004. Synchrony of the Central Atlantic magmatic province and the Triassic?Jurassic boundary climatic and biotic crisis. Geology 32, 973?976.] and Knight et al. [Knight, K.B., Nomade, S., Renne, P.R., Marzoli, A., Betrand, H., Youbi, N., 2004. The Central Atlantic Magmatic Province at the Triassic?Jurassic boundary: paleomagnetic and 40Ar/30Ar evidence from Morocco for brief, episodic volcanism. Earth and Planetary Science Letters 228, 143?160.] as correlates of a very short, uppermost Triassic age reverse chron in the Newark basin, thus suggesting that much of the Moroccan CAMP was synchronous with or predates the Triassic?Jurassic boundary. Here, however, we explain these apparent reverse polarity zones as possible correlatives of poorly sampled lower Jurassic basalt flow sequences and overlying strata in eastern North America and lower Jurassic reverse polarity sequences recognized by others in the Paris basin. A revised Milankovitch cyclostratigraphy based on new core and field data constrains the duration of eastern North America basaltic flows to ? 610 ky after the Triassic?Jurassic palynological turnover event. Palynological data indicates correlation of the initial carbon isotopic excursion of Hesselbo et al. [Hesselbo, S.P., Robinson, S.A., Surlyk, F., Piasecki, S., 2002. Terrestrial and marine extinction at the Triassic?Jurassic boundary synchronized with major carbon-cycle perturbation: a link to initiation of massive volcanism. Geology 30, 251?254.] at St. Audrie's Bay to the palynological turnover event and vertebrate extinction level in eastern North America, suggesting a revised magnetostratigraphic correlation and robust carbon isotopic tests of the Marzoli?Knight hypothesis. We conclude that as yet there are no compelling data showing that any of the CAMP predated or was synchronous with the Triassic?Jurassic extinction event. JF - Palaeogeography, Palaeoclimatology, Palaeoecology VL - 244 KW - triassic KW - jurassic KW - mass extinction KW - central atlantic magmatic province KW - magnetostratigraphy KW - volcanism SN - 0031-0182 TI - Synchrony between the Central Atlantic magmatic province and the Triassic?Jurassic mass-extinction event? SP - 345 AV - none EP - 367 ER - TY - JOUR ID - soton9896 UR - https://eprints.soton.ac.uk/9896/ IS - 4 A1 - Woolf, D.K. A1 - Shaw, A.G.P. A1 - Tsimplis, M.N. Y1 - 2003/// N2 - Satellite altimeter (Topex/Poseidon, 1992?2001) and tide-gauge measurements are used to explore the relationship of the sea level of the North Atlantic and neighbouring seas and coastlines to the North Atlantic Oscillation (NAO). Altimeter measurements suggest significant gyre-scale influence of the NAO in the North Atlantic, but also stronger influences on the continental shelf and inland seas of Europe. A north?south dipole in sea-level anomaly consistent with a hydrostatic response to the NAO sea-level pressure dipole is evident, but there are also large non-hydrostatic effects. The strongest response on the European Shelf is in the southeastern part of the North Sea where sea level is positively correlated to NAO Index. The sea level in two semi-enclosed seas, the Baltic Sea positively and the Mediterranean Sea negatively, is also strongly influenced by the NAO. A weak negative correlation is apparent around the northeastern coastline of North America. These features are confirmed by contemporary coastal tide-gauge data, but the tide-gauge data also show that the influence of the NAO was weaker early in the Twentieth Century (20C) on parts of the Northwest European coastline. Inter-annual sea-level variability associated with fluctuations in the NAO are generally much larger than those associated with secular trends. Inferred multi-decadal fluctuations associated with the NAO are very substantial compared to the 15(35) cm estimated for 20C global sea-level rise (Church, J.A., Gregory, J.M., Huybrechts, P., Kuhn, M., Lambeck, K., Nhuan, M.T., Qin, D. and Woodworth, P.L. (2001). Changes in sea level. Chapter 11 of the Intergovernmental Panel on Climate Change Third Assessment Report, pp. 639?694. Cambridge University Press, Cambridge.) and scenario forecasts for the 21C (350 cm). Therefore, the behaviour of the NAO in the next few decades will be a major regional factor in sea-level rise and coastal vulnerability in some European regions. JF - Journal of Atmosphere and Ocean Science VL - 9 KW - sea level KW - North Atlantic Oscillation KW - climate variability KW - altimeters SN - 1741-7538 TI - The influence of the North Atlantic Oscillation on sea-level variability in the North Atlantic region SP - 145 AV - none EP - 167 ER - TY - RPRT ID - soton65687 UR - https://eprints.soton.ac.uk/65687/ A1 - Wynn, R.B. Y1 - 2009/// N2 - The primary aim of JC027 was to collect sediment cores from a series of deep-water basins
along the northeast Atlantic continental margin, in order to determine the character, frequency
and potential geohazard of landslides and gravity flows in the region. Target areas included the
submarine slopes north of the Canary Islands, the Agadir Basin, the Seine, Horseshoe, Tagus,
Iberia and Biscay Abyssal Plains, and a series of feeder canyons and channels. In addition,
Autosub6000 was deployed on its first scientific missions in order to investigate the erosive
power of large-scale gravity flows in canyon mouth environments.
Despite a late change to the schedule, JC027 proved to be a highly successful cruise. A total
of 63 stations were visited, with deployments including five Autosub6000 dives, five
megacores and 55 piston cores. There was very little weather or technical downtime, which
ensured that all of the main objectives were achieved.
Cruise highlights included 1) recovery of sufficient core data to allow development of a
detailed chrono-stratigraphy for all of the major basins between the Canary Islands and the UK,
aiding identification of areas where landslides and gravity flows may pose a potential
geohazard to European coastlines, 2) collection of a series of spectacular high-resolution
multibeam bathymetry images of giant erosional scours (using Autosub6000), which are
providing new insights into scour formation and the flows that formed them, 3) new data
illustrating the complexity of sedimentary processes and deposits in deep-water environments,
including flow transformations, and 4) new discoveries about seabird distribution and
behaviour in deep-water regions of the northeast Atlantic. PB - National Oceanography Centre T3 - 36 KW - Northeast Atlantic KW - RRS James Cook KW - cruise JC27 2008 KW - Autosub6000 KW - sediment cores KW - submarine geohazards KW - landslides KW - turbidites M1 - project_report TI - RRS James Cook Cruise 27, 05 AUG-03 SEP 2008. Investigating landslide and gravity flow geohazards along the northeast Atlantic continental margin AV - public EP - 25 ER - TY - JOUR ID - soton49400 UR - http://www.journals.royalsoc.ac.uk/content/p074211474031964/ IS - 5 A1 - Wynn, R.B. A1 - Josey, S.A. A1 - Martin, A.P. A1 - Johns, D.G. A1 - Yesou, P. Y1 - 2007/10/22/ N2 - Global climate change is driving rapid distribution shifts in marine ecosystems; these are well established for lower trophic levels, but are harder to quantify for migratory top predators. By analysing a 25-year sightings-based dataset, we found evidence for rapid northwards range expansion of the critically endangered Balearic shearwater Puffinus mauretanicus in northeast Atlantic waters. A 0.6°C sea surface temperature increase in the mid-1990s is interpreted as an underlying controlling factor, while simultaneous northward shifts of plankton and prey fish species suggests a strong bottom-up control. Our results have important conservation implications and provide new evidence for climate-driven regime shift in Atlantic ecosystems.

JF - Biology Letters VL - 3 KW - climate change KW - trophic cascade KW - Atlantic Ocean KW - Balearic shearwater SN - 1744-9561 TI - Climate-driven range expansion of a critically endangered top predator in northeast Atlantic waters SP - 529 AV - none EP - 532 ER - TY - JOUR N1 - Author was at CLIVAR IPO ID - soton5967 UR - http://ams.allenpress.com/amsonline/?request=get-abstract&issn=1520-0442&volume=15&page=2073 IS - 15 A1 - Yan, Z. A1 - Bate, S. A1 - Chandler, R.E. A1 - Isham, V. A1 - Wheater, H. Y1 - 2002/// JF - Journal of Climate VL - 15 KW - NORTH ATLANTIC OSCILLATION KW - ARCTIC OSCILLATION KW - GLOBAL WARMING KW - CLIMATIC CHANGES KW - CLIMATE CHANGE KW - MODELS KW - WIND SPEED KW - METEOROLOGY SN - 0894-8755 TI - An analysis of daily maximum wind speed in Northwestern Europe using generalized models SP - 2073 AV - none EP - 2088 ER - TY - JOUR ID - soton49838 UR - https://eprints.soton.ac.uk/49838/ IS - 22 A1 - Yashayaev, Igor A1 - van Aken, Hendrik M. A1 - Holliday, N. Penny A1 - Bersch, Manfred Y1 - 2007/11// N2 - Development, spreading and decay of the thermohaline properties of two Labrador Sea Water (LSW) classes are described. During the development phase, a specific LSW class repeatedly mixed by winter convection in the Labrador Sea becomes colder, denser, thicker and deeper. Once convection weakens, the LSW class becomes isolated from the upper layer and starts to decay, rapidly losing its volume while retaining the same density due to isopycnal mixing with the neighbouring warm saline intermediate waters. A similar pattern in temperature, salinity and density is seen in the other basins with different time lags from about two years in the Irminger Sea to ten years in the northern Iceland Basin and Rockall Trough regions. The influence of LSW on the thermohaline properties of other North Atlantic water masses is also discussed. JF - Geophysical Research Letters VL - 34 KW - labrador sea water KW - north Atlantic KW - climate change SN - 0094-8276 TI - Transformation of the Labrador Sea water in the subpolar North Atlantic AV - none ER - TY - JOUR ID - soton435111 UR - https://eprints.soton.ac.uk/435111/ A1 - Yeo, I. A. A1 - Howarth, S. A. A1 - Spearman, J. A1 - Cooper, A. A1 - Crossouard, N. A1 - Taylor, J. A1 - Turnbull, M. A1 - Murton, B. J. Y1 - 2019/11/01/ N2 -

Hydrogenetic ferromanganese crusts are likely to be exploited as resources for critical metals in the near future, yet the processes controlling where and how they grow are poorly understood. Using detailed mapping of seafloor outcrop and well constrained hydrographic modelling alongside scanning electron microscope imagery of samples from the Tropic Seamount, a star-shaped guyot located in the Tropical East Atlantic, we investigate the relationship between currents, ferromanganese crustal texture and the locations and intensity of crustal erosion. Here, we report the distribution of FeMn crusts and explore factors controlling their growth and erosion. We find that just over 35% of the summit plateau of the guyot exposes some form of ferromanganese crust mineralisation, with the rest variably covered by plains of mobile sediment and slim cliff exposures of carbonate. The steep flanks of the guyot largely expose ferromanganese crust both in situ and as debris flows. The strongest currents are located on the upper flanks of the guyot, the central part of its eastern limb, and across the summit plateau. Three categories of surface morphologies are identified; from pristine botryoidal surfaces to flat areas that have been completely polished by the erosive action of currents and sediment. The relationship between the outcrop of crusts, their erosional states and the hydrographic current regime to which they are exposed is complicated. There is a general correlation between the degree of erosion and location across the seamount, with the least eroded being found on the flanks below 2000 m water depth and the most heavily eroded crusts largely restricted to the summit area. Furthermore, the pristine samples all reside in areas that rarely experience current magnitudes over 0.2 m/s, suggesting that above this the currents have the ability to erode ferromanganese crust. However, there is a strong overlap between the measured current magnitudes at the locations of partially and completely eroded crusts, as well as partial overlap with the current magnitudes measured at pristine crust locations. This complexity is likely due to the presence of cliffs and plateaus increasing current magnitudes and turbidity at a scale smaller than the model resolution.

JF - Ore Geology Reviews VL - 114 KW - Atlantic KW - Critical elements KW - Ferromanganese crusts KW - Ferromanganese nodules KW - Seafloor mapping KW - Tropic Seamount SN - 0169-1368 TI - Distribution of and hydrographic controls on ferromanganese crusts: Tropic Seamount, Atlantic AV - public ER - TY - JOUR ID - soton424628 UR - https://eprints.soton.ac.uk/424628/ IS - 8 A1 - Yeo, Isobel A. A1 - Dobson, Kate A1 - Josso, Pierre A1 - Pearce, Richard B. A1 - Howarth, Sarah A. A1 - Lusty, Paul A.J. A1 - Le Bas, Tim P. A1 - Murton, Bramley J. Y1 - 2018/08/01/ N2 -

The decarbonisation of our energy supply is reliant on new technologies that are raw material intensive and will require a significant increase in the production of metals to sustain them. Ferromanganese (FeMn) crusts are seafloor precipitates, enriched in metals such as cobalt and tellurium, both of which have a predicted future demand above current production rates. In this study, we investigate the texture and composition of FeMn crusts on Tropic Seamount, a typical Atlantic guyot off the coast of western Africa, as a basis for assessing the future mineral resource potential of Atlantic Seamounts. The majority of the summit is flat and covered by FeMn crusts with average thicknesses of 3?4 cm. The crusts are characterized by two dominant textures consisting of either massive pillared growth or more chaotic, cuspate sections of FeMn oxides, with an increased proportion of detrital and organic material. The Fe, Mn, and Co contents in the FeMn oxide layers are not affected by texture. However, detrital material and bioclasts can form about 50% of cuspate areas, and the dilution effect of this entrained material considerably reduces the Fe, Mn, and Co concentrations if the bulk samples are analyzed. Whilst Tropic Seamount meets many of the prerequisites for a crust mining area, the thickness of the crusts and their average metal composition means extraction is unlikely to be viable in the near future. The ability to exploit more difficult terrains or multiple, closely spaced edifices would make economic feasibility more likely.

JF - Minerals VL - 8 KW - Atlantic KW - Cobalt KW - Crusts KW - Ferromanganese KW - Seafloor mining KW - Seamount SN - 0009-8558 TI - Assessment of the mineral resource potential of atlantic ferromanganese crusts based on their growth history, microstructure, and texture SP - 1 AV - public EP - 19 ER - TY - JOUR ID - soton385047 UR - https://eprints.soton.ac.uk/385047/ IS - 12 A1 - Yool, A. A1 - Popova, E.E. A1 - Coward, A.C. Y1 - 2015/12// N2 - One of the most characteristic features in ocean productivity is the North Atlantic spring bloom. Responding to seasonal increases in irradiance and stratification, surface phytopopulations rise significantly, a pattern that visibly tracks poleward into summer. While blooms also occur in the Arctic Ocean, they are constrained by the sea-ice and strong vertical stratification that characterize this region. However, Arctic sea-ice is currently declining, and forecasts suggest this may lead to completely ice-free summers by the mid-21st century. Such change may open the Arctic up to Atlantic-style spring blooms, and do so at the same time as Atlantic productivity is threatened by climate change-driven ocean stratification. Here we use low and high-resolution instances of a coupled ocean-biogeochemistry model, NEMO-MEDUSA, to investigate productivity. Drivers of present-day patterns are identified, and changes in these across a climate change scenario (IPCC RCP 8.5) are analyzed. We find a globally significant decline in North Atlantic productivity (> ?20%) by 2100, and a correspondingly significant rise in the Arctic (> +50%). However, rather than the future Arctic coming to resemble the current Atlantic, both regions are instead transitioning to a common, low nutrient regime. The North Pacific provides a counterexample where nutrients remain high and productivity increases with elevated temperature. These responses to climate change in the Atlantic and Arctic are common between model resolutions, suggesting an independence from resolution for key impacts. However, some responses, such as those in the North Pacific, differ between the simulations, suggesting the reverse and supporting the drive to more fine-scale resolutions. JF - Journal of Geophysical Research: Oceans VL - 120 KW - marine KW - ocean KW - biogeochemistry KW - arctic KW - atlantic KW - future SN - 2169-9275 TI - Future change in ocean productivity: Is the Arctic the new Atlantic? SP - 7771 AV - public EP - 7790 ER - TY - JOUR ID - soton447456 UR - https://eprints.soton.ac.uk/447456/ IS - 2 A1 - Yu, Xiaolong A1 - Naveira Garabato, Alberto A1 - Martin, Adrian A1 - Marshall, David P. N2 - The evolution of upper-ocean potential vorticity (PV) over a full year in a typical midocean area of the northeast Atlantic is examined using submesoscale- and mesoscale-resolving hydrographic and velocity measurements from a mooring array. A PV budget framework is applied to quantitatively document the competing physical processes responsible for deepening and shoaling the mixed layer. The observations reveal a distinct seasonal cycle in upper-ocean PV, characterized by frequent occurrences of negative PV within deep (up to about 350 m) mixed layers from winter to mid-spring, and positive PV beneath shallow (mostly less than 50 m) mixed layers during the remainder of the year. The cumulative positive and negative subinertial changes in the mixed layer depth, which are largely unaccounted for by advective contributions, exceed the deepest mixed layer by one order of magnitude, suggesting that mixed layer depth is shaped by the competing effects of destratifying and restratifying processes. Deep mixed layers are attributed to persistent atmospheric cooling from winter to mid-spring, which triggers gravitational instability leading to mixed layer deepening. However, on shorter time scales of days, conditions favorable to symmetric instability often occur as winds intermittently align with transient frontal flows. The ensuing submesoscale frontal instabilities are found to fundamentally alter upper-ocean turbulent convection, and limit the deepening of the mixed layer in the winter-to-mid-spring period. These results emphasize the key role of submesoscale frontal instabilities in determining the seasonal evolution of the mixed layer in the open ocean. VL - 51 TI - The annual cycle of upper-ocean potential vorticity and its relationship to submesoscale instabilities AV - public EP - 402 N1 - © Copyright 2021 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact permissions@ametsoc.org. Any use of material in this work that is determined to be ?fair use? under Section 107 of the U.S. Copyright Act (17 U.S. Code §?107) or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC § 108) does not require the AMS?s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. All AMS journals and monograph publications are registered with the Copyright Clearance Center (https://www.copyright.com). Additional details are provided in the AMS Copyright Policy statement, available on the AMS website (https://www.ametsoc.org/PUBSCopyrightPolicy). Y1 - 2021/02// JF - Journal of Physical Oceanography KW - In situ oceanic observations KW - Instability KW - Mixed layer KW - North Atlantic Ocean KW - Potential vorticity KW - Time series SN - 0022-3670 SP - 385 ER - TY - GEN ID - soton432285 UR - https://eprints.soton.ac.uk/432285/ A1 - Zhang, Rong A1 - Sutton, Rowan A1 - Danabasoglu, Gokhan A1 - Kwon, Young Oh A1 - Marsh, Robert A1 - Yeager, Stephen G. A1 - Amrhein, Danial E. A1 - Little, Christopher M. Y1 - 2019/04/29/ N2 -

By synthesizing recent studies employing a wide range of approaches (modern observations, paleo reconstructions, and climate model simulations), this paper provides a comprehensive review of the linkage between multidecadal Atlantic Meridional Overturning Circulation (AMOC) variability and Atlantic Multidecadal Variability (AMV) and associated climate impacts. There is strong observational and modeling evidence that multidecadal AMOC variability is a crucial driver of the observed AMV and associated climate impacts and an important source of enhanced decadal predictability and prediction skill. The AMOC-AMV linkage is consistent with observed key elements of AMV. Furthermore, this synthesis also points to a leading role of the AMOC in a range of AMV-related climate phenomena having enormous societal and economic implications, for example, Intertropical Convergence Zone shifts; Sahel and Indian monsoons; Atlantic hurricanes; El Niño?Southern Oscillation; Pacific Decadal Variability; North Atlantic Oscillation; climate over Europe, North America, and Asia; Arctic sea ice and surface air temperature; and hemispheric-scale surface temperature. Paleoclimate evidence indicates that a similar linkage between multidecadal AMOC variability and AMV and many associated climate impacts may also have existed in the preindustrial era, that AMV has enhanced multidecadal power significantly above a red noise background, and that AMV is not primarily driven by external forcing. The role of the AMOC in AMV and associated climate impacts has been underestimated in most state-of-the-art climate models, posing significant challenges but also great opportunities for substantial future improvements in understanding and predicting AMV and associated climate impacts.

KW - Atlantic Meridional Overturning Circulation KW - Atlantic Multidecadal Variability KW - Climate Impacts KW - Climate Model Biases KW - Decadal Predictability KW - Paleo Reconstructions SN - 8755-1209 TI - A review of the role of the Atlantic meridional overturning circulation in Atlantic multidecadal variability and associated climate impacts AV - public EP - 60 ER - TY - JOUR ID - soton12721 UR - https://eprints.soton.ac.uk/12721/ IS - 17 A1 - Zielinski, O. A1 - Oschlies, A. A1 - Llinas, O. A1 - Reuter, R. Y1 - 2002/// N2 - Light abundance is a major prerequisite for primary production in pelagic ecosystems, influencing the evolution of the marine environment. Realistic simulations of planktonic ecosystems therefore require an appropriate representation of the underwater light field. Taking a look at the different biogeochemical models discussed in literature, one finds a variety of descriptions for the distribution of light, or more specific, photosynthetically available radiation (PAR) in the water column. This paper compares the effect of different parameterizations of PAR on the primary production and phytoplankton evolution at the European Station for Time-Series in the Ocean Canary Islands (ESTOC) station (29°10?N, 15°30?W) north of Gran Canaria, Canary Islands. Observations from two cruises in 1997 are used to illustrate the winter and spring situation at the time-series site. Four alternative PAR descriptions are used in a one-dimensional coupled biological?physical model of the upper ocean driven by daily forcing fields over a 5-year period. The biological model is a simple nitrate-phytoplankton?zooplankton-detritus model. Although the different descriptions are found to have only a small effect (±3%) on the annual primary production, we observe significant changes in the vertical distribution of simulated phytoplankton. The large variation (±32%) in the near-surface chlorophyll contents will be of particularly crucial importance when using satellite ocean-color sensors for model validation and parameter estimation. For future three-dimensional biogeochemical models, a computationally efficient and accurate parameterization of the light field will be particularly relevant. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 49 KW - Atlantic Ocean KW - Canary Islands KW - ESTOC (29°10?N KW - 15°30?W) SN - 0967-0645 TI - Underwater light field and its effect on a one-dimensional ecosystem model at station ESTOC, north of the Canary Islands SP - 3259 AV - none EP - 3542 ER - TY - JOUR ID - soton337460 UR - https://eprints.soton.ac.uk/337460/ IS - 8 A1 - Zika, Jan D. A1 - McDougall, Trevor J. A1 - Sloyan, Bernadette M. Y1 - 2010/08// N2 - The tracer-contour inverse method is used to infer mixing and circulation in the eastern North Atlantic. Solutions for the vertical mixing coefficient D, the along-isopycnal mixing coefficient K, and a geostrophic streamfunction ? are all direct outputs of the method. The method predicts a vertical mixing coefficient O(10?5 m2 s?1) in the upper 1000 m of the water column, consistent with in situ observations. The method predicts a depth-dependent along-isopycnal mixing coefficient that decreases from O(1000 m2 s?1) close to the mixed layer to O(100 m2 s?1) in the interior, which is also consistent with observations and previous hypotheses. The robustness of the result is tested with a rigorous sensitivity analysis including the use of two independently constructed datasets.

This study confirms the utility of the tracer-contour inverse method. The results presented support the hypothesis that vertical mixing is small in the thermocline of the subtropical Atlantic Ocean. A strong depth dependence of the along-isopycnal mixing coefficient is also demonstrated, supporting recent parameterizations for coarse-resolution ocean models. JF - Journal of Physical Oceanography VL - 40 KW - Mixing KW - North Atlantic KW - Tracers KW - Ocean circulation SN - 0022-3670 TI - Weak Mixing in the Eastern North Atlantic: An Application of the Tracer-Contour Inverse Method SP - 1881 AV - none EP - 1893 ER - TY - JOUR ID - soton348364 UR - https://eprints.soton.ac.uk/348364/ IS - 7 A1 - de Jong, M.F. A1 - Drijfhout, S.S. A1 - Hazeleger, W. A1 - van Aken, H.M. A1 - Severijns, C.A. Y1 - 2009/04// N2 - The performance of coupled climate models (CCMs) in simulating the hydrographic structure and variability of the northwestern North Atlantic Ocean, in particular the Labrador and Irminger Seas, has been assessed. This area plays an important role in the meridional overturning circulation. Hydrographic properties of the preindustrial run of eight CCMs used in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) are compared with observations from the World Ocean Circulation Experiment Repeat section 7 (WOCE AR7). The mean and standard deviation of 20 yr of simulated data are compared in three layers, representing the surface waters, intermediate waters, and deep waters. Two models simulate an extremely cold, fresh surface layer with model biases down to ?1.7 psu and ?4.0°C, much larger than the observed ranges of variability. The intermediate and deep layers are generally too warm and saline, with biases up to 0.7 psu and 2.8°C. An analysis of the maximum mixed layer depth shows that the low surface salinity is related to a convective regime restricted to the upper 500 dbar. Thus, intermediate water formed by convection is partly replaced by warmer water from the south. Model biases seem to be caused by the coupling to the atmospheric component of the CCM. Model drift during long spinup periods allows the initially small biases in water mass characteristics to become significant. Biases that develop in the control run are carried over to the twentieth-century runs, which are initialized from the control runs. JF - Journal of Climate VL - 22 KW - coupled models KW - north atlantic ocean KW - climate models SN - 0894-8755 TI - Simulations of hydrographic properties in the northwestern North Atlantic Ocean in coupled climate models SP - 1767 AV - none EP - 1786 ER - TY - JOUR ID - soton423761 UR - https://eprints.soton.ac.uk/423761/ A1 - van den Berk, J. A1 - Drijfhout, S. S. A1 - Hazeleger, W. Y1 - 2018/09/18/ N2 -

The impact of an idealised scenario of future mass release of major ice sheets on the Atlantic ocean is studied. A freshwater forcing is applied to the ocean surface in a coupled climate model forced in accordance with a high-end future climate projection for mass loss from the Greenland and Antarctic ice-sheet, together with the RCP8.5 emission scenario. The added freshwater dilutes the entire ocean by increasing total volume, but changes in freshwater budget are non-linear in time, especially in the Atlantic Ocean. In the Atlantic the initial dilution mainly comes from Greenland freshwater, but the increase in mass is counteracted by the mass flux across the boundaries of the Atlantic, with the outflow into the Southern Ocean becoming larger than the inflow through Bering Strait. Associated with this mass divergence, salt is exported to the Southern Ocean by the barotropic flow. Further freshening is associated with more freshwater import by the Atlantic Meridional Overturning Circulation across the southern boundary of the Atlantic. Also, the subtropical gyre exports salt and imports freshwater across the Atlantic?s southern boundary, especially when freshwater from the Antarctic Ice Sheet arrives at the boundary of the basin. It appears that the response to Northern Hemisphere (NH) sources (the Greenland Ice Sheet) and Southern Hemisphere (SH) sources (the Antarctic Ice Sheet) are opposite. In the case of NH-only freshwater forcing, sea surface height (SSH) increases in the Arctic, causing a reduction of the SSH gradient over the Bering Strait, and hence the barotropic throughflow across the Arctic?Atlantic basin reduces. In case of SH-only freshwater forcing, SSH increases in the Pacific, enhancing the barotropic throughflow in the Arctic?Atlantic. When both NH and SH freshwater forcings are present, the response in the Atlantic is dominated by NH forcing. Changes in overturning transport to either NH or SH forcing counteract the response to changes in barotropic transport. These changes are not due to volume transport but mainly due to salinity changes, in particular across the southern boundary of the Atlantic. Only when both SH and NH freshwater forcing are present changes in barotropic transport and overturning transport reinforce each other: the barotropic transport more strongly reacts to NH forcing, while the overturning transport reacts more strongly to SH forcing.

JF - Climate Dynamics KW - Atlantic Ocean KW - Coupled climate models KW - Meltwater KW - Salinity budget SN - 0930-7575 TI - Atlantic salinity budget in response to Northern and Southern Hemisphere ice sheet discharge AV - public EP - 19 ER - TY - JOUR ID - soton368654 UR - https://eprints.soton.ac.uk/368654/ A1 - van den Berk, J. A1 - Drijfhout, S.S. Y1 - 2014/09// N2 - A high-end scenario of polar ice loss from the Greenland and Antarctic ice sheet is presented with separate projections for different mass-loss sites up to the year 2100. For each large ice sheet three potential sources of freshwater release to the ocean are considered: run-off from surface melt, basal melt through heat exchange with the ocean, and iceberg calving and subsequent mass loss through melt of drifting icebergs. The location and relative magnitude of freshwater forcing due to drifting icebergs is calculated from a separate iceberg drift simulation. We assume fixed annual spatial patterns with magnitudes varying in time. These magnitudes are based on a severe warming scenario based on expert elicitation. The resultant freshwater forcing is applied to a global climate model and the effects on sea-level rise are discussed. The simulations show strong sea level rise on the Antarctic continental shelves. The effect on the Atlantic overturning circulation is very small, however. JF - Ocean Modelling VL - 81 KW - Surface freshwater flux KW - Global ocean model KW - North Atlantic KW - Southern ocean SN - 1463-5003 TI - A realistic freshwater forcing protocol for ocean-coupled climate models SP - 36 AV - public EP - 48 ER - TY - JOUR ID - soton349170 UR - https://eprints.soton.ac.uk/349170/ IS - 3-4 A1 - van der Schrier, G. A1 - Weber, S.L. A1 - Drijfhout, S.S. A1 - Lowe, J.A. Y1 - 2004/11// N2 - The control run of the Hadley Centre-coupled climate model (HadCM3) is used to establish the sources of multidecadal/centennial sea level (SL) variations in the northwest Atlantic. It is shown that variations in the sea level for the largest part of this area are related to variations in the thermohaline structure of the upper (?500 m) part of the ocean. Temperature variations dominate steric sea level variations, while salinity variations are dominant only in the margins of the Labrador Sea and near the Mediterranean outflow. In the Labrador Sea, lower layers in the ocean also contribute to the variability in expansion/contraction of the water column. It is shown that along the North American East Coast, variations in the thermohaline structure of the water column are predominantly related to variations in the wind-driven circulation rather than the thermohaline circulation, which dominates the thermohaline structure in the central parts of the North Atlantic. In the Gulf Stream area and near the Labrador Current, sea level has on the multidecadal/centennial time scale a strong barotropic signal superposed on steric sea level variations. JF - Global and Planetary Change VL - 43 KW - sea level KW - north atlantic KW - ocean circulation KW - climate modelling SN - 0921-8181 TI - Low-frequency Atlantic sea level variability SP - 129 AV - none EP - 144 ER -