TY - RPRT ID - soton342629 UR - https://eprints.soton.ac.uk/342629/ Y1 - 2012/09/05/ PB - International CLIVAR Project Office T3 - 180 KW - Clivar KW - Climate KW - Southern Oceans M1 - project_report TI - Report of the 7th Meeting of CLIVAR/CliC/SCAR Southern Ocean Region Implementation Panel, 19-21 October 2011, Bolder USA AV - public EP - 18 ER - TY - RPRT N1 - WCRP Informal Report No: 6/2011 ID - soton196497 UR - https://eprints.soton.ac.uk/196497/ Y1 - 2011/09/08/ PB - International CLIVAR Project Office T3 - 148 KW - CLIVAR KW - CliC KW - SCAR KW - southern ocean region panel KW - meridional circulation KW - southern ocean KW - ICPO KW - climate change M1 - project_report TI - Report of the 6th Meeting of the CLIVAR/CliC/SCAR Southern Ocean region panel and the workshop on the upper and lower cells of the meridional circulation in the Southern Ocean, National Oceanography Centre, Southampton, UK 14 - 17th June 2010 AV - public EP - 34 ER - TY - RPRT N1 - WCRP Informal Report No. 4/2007 ID - soton47521 UR - https://eprints.soton.ac.uk/47521/ Y1 - 2007/06// PB - International CLIVAR Project Office T3 - 113 KW - CLIVAR KW - WCRP KW - CliC KW - SCAR KW - Southern Ocean KW - Climate Change M1 - project_report TI - Report of the 4th Meeting of the CLIVAR/CliC/SCAR Southern Ocean Region Panel, 14 and 17 November 2006, Palacio San Martín, Ministry of Foreign Affairs, Buenos Aires, Argentina AV - public EP - 17 ER - TY - RPRT N1 - WCRP Informal Report No. 19/2006 ID - soton47558 UR - https://eprints.soton.ac.uk/47558/ Y1 - 2006/10// PB - International CLIVAR Project Office T3 - 109 KW - CLIVAR KW - WCRP KW - VACS KW - Southern and Eastern Africa KW - Climate Predictability M1 - project_report TI - Report of the CLIVAR VACS Southern and Eastern African Climate Predictability Workshop, Tanzania Meteorological Agency, Dar es Salaam, 10-13th July 2006 AV - public EP - 12 ER - TY - RPRT N1 - WCRP Informal Report No. 7/2006 ID - soton41424 UR - https://eprints.soton.ac.uk/41424/ Y1 - 2006/08// PB - International CLIVAR Project Office T3 - 102 KW - CLIVAR KW - WCRP KW - ocean model development KW - southern ocean modelling KW - WGOMD M1 - project_report TI - Report on the WGOMD Workshop on Southern Ocean Modelling, Hobart, Australia, 9-10 November 2005 AV - public EP - 20 ER - TY - RPRT N1 - WCRP Informal Report No. 15/2005 ID - soton19361 UR - https://eprints.soton.ac.uk/19361/ Y1 - 2005/12// PB - International CLIVAR Project Office T3 - 98 KW - CLIVAR KW - WCRP KW - CliC KW - SCAR KW - Southern Ocean KW - modes KW - variability M1 - project_report TI - Reports of the Modes of Southern Hemisphere Climate Variability Workshop (27-28 June 2005) and the Third Session of the CLIVAR/CliC/SCAR Southern Ocean Region Panel (29-30 June 2005), Cambridge, UK AV - public EP - 39 ER - TY - RPRT ID - soton18758 UR - https://eprints.soton.ac.uk/18758/ Y1 - 2004/03// PB - International CLIVAR Project Office T3 - 76 KW - CLIVAR KW - WCRP KW - CliC KW - Southern Ocean M1 - project_report TI - Report of the Second Session of the CLIVAR/CliC Southern Ocean Panel, Bremerhaven, Germany, 8-11 September 2003 AV - public EP - 32 ER - TY - RPRT N1 - WCRP Informal Report No. 16/2002 ID - soton19177 UR - https://eprints.soton.ac.uk/19177/ Y1 - 2002/08// PB - International CLIVAR Project Office T3 - 65 KW - CLIVAR KW - WCRP KW - CliC KW - Southern Ocean M1 - project_report TI - Report of the 1st Session of the CLIVAR/Clic Southern Ocean Panel, Hobart, Australia, March 11-13, 2002 AV - public EP - 36 ER - TY - JOUR ID - soton457911 UR - https://eprints.soton.ac.uk/457911/ A1 - Ahmed, Abdulhakim A1 - Doubre, Cecile A1 - Leroy, Sylvie A1 - Keir, Derek A1 - Pagli, Carolina A1 - Hammond, James O.S. A1 - Ayele, Atalay Y1 - 2022/08/01/ N2 - We used teleseismic receiver function analysis to image the crustal structure beneath 24 broadband seismic stations densely deployed along two profiles traversing different structural units across the western Afar margin. Our high-resolution receiver function results image pronounced spatial variations in the crustal structure along the profiles and provide improved insights to understand how strain is partitioned in the crust during rifting. Beneath the western plateau next to northern Afar, the crust is likely felsic-to-intermediate in composition (average Vp/Vs 1.74), with a step like thinning of the crust from an average of 38 km beneath the western plateau to an average of 22 km beneath the marginal graben. Consistently thicker crust is observed beneath the southern profile (central Afar), showing four distinct regions of uniform crustal thickness: 1) an average crustal thickness of 42 km beneath the western plateau; 2) 34 km beneath the foothills area; 3) 28 km beneath the marginal graben and the wide extensional basin and 4) 21 km beneath the central rift axis. We use crustal thickness results to estimate a stretching factor ? of 2.2 and 2.7 for central Afar and northern Afar respectively. Our estimated values are lower than ? > 3.0 predicted from plate reconstructions, and we interpret that the variations are best explained by 2?5 km magmatic addition into the crust. The crustal composition beneath the southern profile is more complex with elevated Vp/Vs ratios ranging between 1.79 and 1.85 beneath the western plateau and marginal graben. This is consistent with a greater mafic component and best explained by crust altered by intrusions due to significant pre and syn-rift magmatic activity. Abnormally high Vp/Vs ratios of more than 1.90 are observed beneath the axial rift zone of central Afar, which most likely suggests the localization of partial melt within the crust. JF - Journal of African Earth Sciences VL - 192 KW - Afar margin KW - Africa KW - Continental margin KW - Crustal structure KW - Receiver functions KW - Southern red sea rift SN - 1464-343X TI - Across and along-strike crustal structure variations of the western Afar margin and adjacent plateau: Insights from receiver functions analysis AV - public EP - 16 ER - TY - JOUR N1 - Funding Information: The authors thank the chief scientist Gideon Henderson, and the captains, crews and all of the scientists on both legs of the NERC funded UK-GEOTRACES GA10 section (D357 and JC068), grant # NE/H004475/1 to MCL. We thank Shotaro Takano and Urs Menet for their assistance in the lab. We thank Wafa Abouchami for providing some of the samples used for this work. We are also grateful to Tom Browning for fruitful discussions during the preparation of this manuscript. We are also grateful for the editorial handling of this manuscript, and the comments of two anonymous reviewers. This research was supported by ETH Zürich and Swiss SNF grant 200020_165904 . Publisher Copyright: © 2020 Elsevier B.V. ID - soton441295 UR - https://eprints.soton.ac.uk/441295/ A1 - Archer, Corey A1 - Vance, Derek A1 - Milne, Angela A1 - Lohan, Maeve C. Y1 - 2020/04/01/ N2 -
Nickel (Ni) is important for a number of enzymes in oceanic phytoplankton. It has received less attention than some other bioactive metals because it is not reduced to extremely low dissolved concentrations in the photic zone. However, there are strong indications in previous studies that this residual pool is not bio-available. Oceanic Ni isotope data are still scarce, but have great potential for understanding this issue, as well as for understanding the Ni mass balance of the oceans now and in the past. Here, we present new concentration and isotope data for the UK GEOTRACES section at 40°S in the Atlantic (GA10). Nickel concentration data show typical nutrient-like profiles, slightly modified by variable pre-formed concentrations in sub-surface water masses, e.g. North Atlantic Deep Water. Nickel isotopes, in common with findings in previous studies, are homogeneous beneath 500 m, at about +1.3? in ? 60Ni, in samples with Ni concentrations above 3-3.5 nM. The surface South Atlantic, however, has concentrations below 3 nM, and shows significantly higher ? 60Ni, up to +1.74?, that are closely anti-correlated with Ni concentrations. The data for the deep South Atlantic dissolved pool, with a ? 60Ni = 1.31 ± 0.12? (average and 2SD) confirm the homogeneity of the global deep ocean, which previous data demonstrate extends all the way to the surface in the upwelling zone of the Southern Ocean south of the Polar Front. This Ni isotope composition is significantly heavier than known inputs to the oceanic dissolved pool. This mass balance requires an isotopically light sink that may be represented by sedimentary Mn-oxide associated Ni. The magnitude of the isotope fractionation implied by the upper ocean data is not consistent with plausible potential abiotic removal processes. Rather, these data are best explained by biological uptake. However, consideration of the detailed relationships between Ni concentrations and isotope compositions requires that a substantial portion of the oceanic dissolved Ni pool is not bio-available. The data are consistent either with a small preference for the light isotope during uptake (about 0.1?) or two distinct pools of dissolved Ni, one bio-available and one strongly bound in organic complexes, with limited isotopic exchange between them. Patterns of co-variation in Ni concentrations and isotopes with the major nutrients point to strong contrasts across the Polar Front of the Southern Ocean, contrasts that exhibit both similarities and differences with those for the major nutrients and other trace metal micronutrients. South of the Polar Front, Ni is taken up in modest amounts by diatoms, without isotope fractionation. North of the Polar Front the data are most consistent with cyanobacteria as the dominant control on Ni uptake, leading to significant coupled abundance and isotope variation.
JF - Earth and Planetary Science Letters VL - 535 KW - Antarctic Polar Front KW - GEOTRACES KW - Southern Ocean biogeochemistry KW - nickel isotopes SN - 0012-821X TI - The oceanic biogeochemistry of nickel and its isotopes: New data from the South Atlantic and the Southern Ocean biogeochemical divide AV - none ER - TY - JOUR ID - soton381289 UR - https://eprints.soton.ac.uk/381289/ IS - 42 A1 - Aronson, R.B. A1 - Smith, K.E. A1 - Vos, S.C. A1 - McClintock, J.B. A1 - Amsler, M.O. A1 - Moksnes, P.O. A1 - Ellis, D.S. A1 - Kaeli, J.W. A1 - Singh, H. A1 - Bailey, J.W. A1 - Schiferl, J.C. A1 - van Woesik, R. A1 - Martin, M.A. A1 - Steffel, B.V. A1 - Deal, M.E. A1 - Lazarus, S.M. A1 - Havenhand, J.N. A1 - Swalethorp, R. A1 - Kjellerup, S. A1 - Thatje, S. Y1 - 2015/10/20/ N2 - Cold-water conditions have excluded durophagous (skeleton-breaking) predators from the Antarctic seafloor for millions of years. Rapidly warming seas off the western Antarctic Peninsula (WAP) could now facilitate their return to the continental shelf, with profound consequences for the endemic fauna. Among the likely first arrivals are king crabs (Lithodidae), which were discovered recently on the adjacent continental slope. During the austral summer of 2010-2011, we used underwater imagery to survey a slope-dwelling population of the lithodid Paralomis birsteini off Marguerite Bay, WAP for environmental or trophic impediments to shoreward expansion. The average density was ~4.5 ind·1000m-2 within a depth-range of 1100-1500 m (overall observed depth-range 841?2266 m). Evidence of juveniles, molting, and precopulatory behavior suggested a reproductively viable population on the slope. At the time of the survey, there was no thermal barrier to prevent the lithodids from expanding upward and emerging on the outer shelf (400?500 m depth); however, near-surface temperatures remained too cold for them to survive in shallow, coastal environments (<200 m). Ambient salinity, composition of the substrate, and the depth-distribution of potential predators likewise indicated no barriers to expansion onto the outer shelf. Primary food resources for lithodids?echinoderms and mollusks?were abundant on the upper slope (500?800 m) and outer shelf. At present rates of warming, lithodids should emerge in outer-shelf environments within several decades. As sea temperatures continue to rise, they will likely play an increasingly important trophic role in subtidal communities closer to shore. JF - Proceedings of the National Academy of Sciences VL - 112 KW - biological invasion KW - polar emergence KW - climate change KW - predation KW - Southern Ocean SN - 0027-8424 TI - No barrier to emergence of bathyal king crabs on the Antarctic shelf SP - 12997 AV - none EP - 13002 ER - TY - RPRT ID - soton286 UR - https://eprints.soton.ac.uk/286/ A1 - Bacon, S Y1 - 2003/// N2 - This report describes the eighth repeat hydrography section across Drake Passage, first established during the World Ocean Circulation Experiment. Thirty CTD/LADCP stations were carried out across the 753 km section from Elephant Island to Burdwood Bank, plus one test station and one station at the Rothera Time Series (RaTS) site, just off Biscoe Wharf at Rothera. Maximum station spacing on theThe Marine Mammal Programme (MMP) conducts research on pinnipeds and killer whales Orcinus orca at Marion Island, Prince Edward Islands, under the auspices of the Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria. The history of the MMP, which has benefited from collaboration with leading national and international researchers, is described from its start through to current research. The setting up of long-term studies such as the mark-resighting of southern elephant seals Mirounga leonina commenced in 1983. The elephant seal population declined by 87% between an initial census in 1951 and 2004. This was followed by a stabilisation period and a current increase. The recovery, and subsequent increase of sympatric populations of Subantarctic fur seals Arctocephalus tropicalis and Antarctic fur seals A. gazella (following cessation of commercial sealing), are documented. Insights into many aspects of elephant seal and fur seal biology, including life history, demography, diet, growth, foraging and ranging behaviour are described. Ancillary work on morphology, genetics, anthropogenic influences and rare events are mentioned, as well as the extent of current research that addresses population dynamics in an ecosystem context. Opportunistic photographic identification of killer whales and recent dedicated observations at Marion Island are used to determine population size, seasonal abundance and sociality of this population, and to further understanding of its potential impact on resident pinniped populations.
VL - 33 TI - The Marine Mammal Programme at the Prince Edward Islands: 38 years of research AV - none EP - 521 N1 - Funding Information: Acknowledgements ? Research at the PEIA was first funded by the Department of Transport, which also provided the logistics, and later by the Department of Environmental Affairs and Tourism, under the auspices of various research committees. Currently, funding is provided by the South African Department of Science and Technology, administered by the National Research Foundation, while the Department of Environmental Affairs provides the logistics. We are indebted to numerous personnel for their dedicated work on Marion Island when we were not in the field (see http://marion. sanap.org.za/index2.html), and to Azwianewi Makhado for setting the standard for students from the University of Venda that came after him. Richard Laws, Donald Siniff, John Bengtson and Ian Boyd, then members of the Scientific Committee for Antarctic Research Group of Specialists on Seals, provided their individual support in the 1990s when the long-term elephant seal mark-resighting progamme at the PEIA was under threat of being discontinued. Clarke Scholtz and Sue Nicolson as heads of department, and Johan du Toit and Elissa Cameron as directors of the MRI, were supportive throughout their tenures. Harry Burton, Joachim Plötz, Brent Stewart, John Arnould and Martin Haupt provided materially and spiritually, and Horst Bornemann, Alejandro Carlini?, Mark Hindell and Mirtha Lewis made meaningful collaboration possible. Graham Kerley, Ian Wilkinson, Greg Hofmeyr, Steve Kirkman, Pierre Pistorius (Marion Island expeditioners, students and friends all rolled into one), and Clive McMahon (Marion cat hunter, Macquarie sealer, student and friend), contributed enormously to the productivity of the MMP, each spending at least two seasons in the field and producing dissertations/theses and papers while at home base. We dedicate this paper to the memory of Alejandro Carlini, valued friend and colleague at IAA, who tragically passed away in the prime of his life in December 2010. Funding Information: Between April 1981 and March 1996, coordination of the overall research effort was facilitated by the appointment of a dedicated Antarctic Research Officer (ARO) within the South African National Antarctic Programme (SANAP). This position was located at the MRI, and although the ARO position was terminated in 1996, the officer (MNB) subsequently procured a permanent, full-time academic position within the Department of Zoology and Entomology at the University of Pretoria (UP) in April 1996. This ensured continuity in research. Seal research collaborations were forged especially with the then Branch: Marine and Coastal Management (now Oceans and Coasts of the Department of Environmental Affairs [DEA]), the University of Cape Town, the University of Venda, Port Elizabeth Museum at Bayworld, the Alfred Wegener Institute for Polar and Marine Research (Germany), Australian Antarctic Division, Hubbs-Sea World Research Institute (USA), Norwegian Polar Institute, Instituto Antartico Argentino (IAA), the Centro Nacional Patagonico (CENPAT) (Argentina), Deakin University (Australia) and the University of Tasmania (Australia). These collaborations continue to the present. The appointment of a UP graduate associated with the MMP (PJNdB) to a permanent, full-time academic position within the Department of Zoology and Entomology (January 2010), and alliances formed with other former MMP participants now employed at Oceans and Coasts, Nelson Mandela Metropolitan University (NMMU), Port Elizabeth Museum at Bayworld, and University of Venda, promise to be significant in the continuation and expansion of the MRI?s drive towards a strong and scientifically productive involvement in SANAP and other national Antarctic programmes through the study of marine mammals. However, this will be subject to continued procurement of funding from the Department of Science and Technology within SANAP. Copyright: Copyright 2012 Elsevier B.V., All rights reserved. Y1 - 2011/11// JF - African Journal of Marine Science KW - Antarctic fur seal KW - foraging ecology KW - killer whale KW - population dynamics KW - southern elephant seal KW - Subantarctic fur seal SN - 1814-232X SP - 511 ER - TY - JOUR ID - soton354201 UR - https://eprints.soton.ac.uk/354201/ A1 - Billett, D.S.M. A1 - Bett, B.J. A1 - Evans, R. A1 - Cross, I. A1 - Tyler, P.A. A1 - Wolff, G.A. Y1 - 2013/08// N2 - The reproductive characteristics of six ophiuroid species, Ophiura irrorata loveni, Ophiura lienosa, Amphioplus daleus, Ophiacantha cosmica, Ophiernus quadrispinus and Ophioplexa condita, were studied at two localities in the vicinity of the Crozet Islands in the Southern Indian Ocean. The two localities were notable in having almost identical environmental characteristics other than major differences in surface-water primary productivity and organic matter flux. The two localities were only 460 km apart. Three species were sufficiently abundant at the two sites to compare their reproductive biology under different productivity regimes. Ophiura irrorata loveni showed significant differences in oocyte size distributions and population size distributions between the two sites. The differences appeared to be related to the characteristics of organic matter flux at the two localities. Ophiacantha cosmica and Ophioplexa condita showed differences in abundance between the two sites. This appeared to be related to the availability of suitable substrata. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 92 KW - Ophiuroid KW - Southern Indian Ocean KW - Crozet KW - Reproductive ecology KW - Ocean productivity KW - Benthos SN - 0967-0645 TI - The reproductive ecology of deep-sea ophiuroids around the Crozet plateau, Southern Indian ocean, under contrasting productivity regimes SP - 18 AV - none EP - 26 ER - TY - JOUR ID - soton342694 UR - https://eprints.soton.ac.uk/342694/ A1 - Boersch-Supan, P.H. A1 - Boehme, L. A1 - Read, J.F. A1 - Rogers, A.D. A1 - Brierley, A.S. Y1 - 2012/// N2 - McIntyre et al. (2011; Mar Ecol Prog Ser 441:257?272) concluded that climate change-related ocean warming may lead to deeper foraging dives by southern elephant seals as their prey is forced into deeper depths. They further assert that fitness for the seals will be reduced because of greater physiological costs for deep dives and the assumption that deep foraging is less successful. Their conclusions are based on an observed correlation between a temperature index and elephant seal diving depth but do not include any observations of prey. We recently observed pronounced differences in the vertical distribution of pelagic biota?biota that may well include elephant seal prey?across the same frontal zone considered by McIntyre et al. (2011) and believe that their suggested link between temperature and diving depth is actually a link between predators and distinct prey fields?a reflection of adaptive foraging behaviour in a complex and dynamic pelagic system. As such, the analysis of McIntyre et al. (2011) is uninformative about likely impacts of ocean warming. JF - Marine Ecology Progress Series VL - 461 KW - Climate change KW - Effect size KW - Prey field KW - Vertical structure KW - Southern elephant seal KW - Foraging ecology KW - Deep scattering layer TI - Elephant seal foraging dives track prey distribution, not temperature: Comment on McIntyre et al. (2011) SP - 293 AV - none EP - 298 ER - TY - JOUR ID - soton335888 UR - https://eprints.soton.ac.uk/335888/ A1 - Bohaty, Steven M. A1 - Zachos, James C. A1 - Delaney, Margaret L. Y1 - 2012/02/01/ N2 - Constraining the magnitude of high-latitude temperature change across the Eocene?Oligocene transition (EOT) is essential for quantifying the magnitude of Antarctic ice-sheet expansion and understanding regional climate response to this event. To this end, we constructed high-resolution stable oxygen isotope (?18O) and magnesium/calcium (Mg/Ca) records from planktic and benthic foraminifera at four Ocean Drilling Program (ODP) sites in the Southern Ocean. Planktic foraminiferal Mg/Ca records from the Kerguelen Plateau (ODP Sites 738, 744, and 748) show a consistent pattern of temperature change, indicating 2?3 °C cooling in direct conjunction with the first step of a two-step increase in benthic and planktic foraminiferal ?18O values across the EOT. In contrast, benthic Mg/Ca records from Maud Rise (ODP Site 689) and the Kerguelen Plateau (ODP Site 748) do not exhibit significant temperature change. The contrasting temperature histories derived from the planktic and benthic Mg/Ca records are not reconcilable, since vertical ?18O gradients remained nearly constant at all sites between 35.0 and 32.5 Ma. Based on the coherency of the planktic Mg/Ca records from the Kerguelen Plateau sites and complications with benthic Mg/Ca paleothermometry at low temperatures, the planktic Mg/Ca records are deemed the most reliable measure of Southern Ocean temperature change. We therefore interpret a uniform cooling of 2?3 °C in both deep surface (thermocline) waters and intermediate deep waters of the Southern Ocean across the EOT. Cooling of Southern Ocean surface waters across the EOT was likely propagated to the deep ocean, since deep waters were primarily sourced on the Antarctic margin throughout this time interval. Removal of the temperature component from the observed foraminiferal ?18O shift indicates that seawater ?18O values increased by 0.6 ± 0.15? across the EOT interval, corresponding to an increase in global ice volume to a level equivalent with 60?130% modern East Antarctic ice sheet volume. JF - Earth and Planetary Science Letters VL - 317-318 KW - Foraminifera KW - Eocene KW - Oligocene KW - Southern Ocean KW - Stable oxygen isotopes KW - Mg/Ca KW - Ocean Drilling Program SN - 0012-821X TI - Foraminiferal Mg/Ca evidence for Southern Ocean cooling across the Eocene?Oligocene transition SP - 251 AV - none EP - 261 ER - TY - JOUR ID - soton338393 UR - https://eprints.soton.ac.uk/338393/ IS - 1 A1 - Bosserelle, Cyprien A1 - Pattiaratchi, Charitha A1 - Haigh, Ivan Y1 - 2012/// N2 - Quantifying the long-term variability in wave conditions incident on a coastline is critical for predicting its resilience to future changes in the wave climate. In this study, a 40-year wave hindcast of the southern Indian Ocean has been created to assess the inter-annual variability and longer-term changes in the wave climate around Western Australia (WA) between 1970 and 2009. The model was validated against measurements from five wave buoys located along the WA coast. Changes in the mean annual significant wave height, 90th percentile wave height, peak period and mean wave direction were assessed, and the tracks of all wave events generating wave heights above 7 m were digitised and analysed for significant changes. Results show strong annual and inter-annual variability in the mean significant wave height, the 90th percentile wave height and the number of large events (wave height?>?7 m) that impact the WA coastline. A significant positive trend in annual mean wave height was found in the southwest region of WA over the 40-year simulation. This appears to be due to an increase in intensity of the storm belt in the Southern Ocean which is associated with an increasing positive polarity in the Southern Annular Mode. However, no significant trends were found in the 90th percentile wave height or the number of large wave events impacting Western Australia. Although the number of large wave events in the southern Indian Ocean have increased, their potential to impact the coastal regions of Western Australia are reduced due to storm tracks being located further south, therefore balancing the number of large wave events reaching the WA coast. JF - Ocean Dynamics VL - 62 KW - Wave climate KW - Western Australia KW - Southern Indian Ocean SN - 1616-7341 TI - Inter-annual variability and longer-term changes in the wave climate of Western Australia between 1970 and 2009 SP - 63 AV - none EP - 76 ER - TY - JOUR ID - soton6141 UR - https://eprints.soton.ac.uk/6141/ IS - 3 A1 - Boswell, S.M. A1 - Smythe-Wright, D. Y1 - 2002/// JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 49 KW - WOCE KW - COUNTRYGB KW - TRACERS KW - DEEP WATER MASSES KW - ANTARCTIC BOTTOM WATER KW - SOUTHERN OCEAN SN - 0967-0637 TI - The tracer signature of Antarctic bottom water and its spread in the Southwest Indian Ocean: Part I - CFC-derived translation rate and topographic control around the Southwest Indian Ridge and the Conrad Rise SP - 555 AV - none EP - 573 ER - TY - JOUR ID - soton6142 UR - https://eprints.soton.ac.uk/6142/ IS - 3 A1 - Boswell, S.M. A1 - Smythe-Wright, D. A1 - Holley, S.E. A1 - Kirkwood, D. Y1 - 2002/// JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 49 KW - WOCE KW - COUNTRYGB KW - TRACERS KW - SILICON CYCLE KW - BIOGEOCHEMISTRY KW - SOUTHERN OCEAN KW - ANTARCTIC OCEAN SN - 0967-0637 TI - The tracer signature of Antarctic bottom water and its spread in the Southwest Indian Ocean: Part II - Dissolution fluxes of dissolved silicate and their impact on its use as a chemical tracer SP - 575 AV - none EP - 590 ER - TY - JOUR ID - soton49372 UR - https://eprints.soton.ac.uk/49372/ IS - 16-17 A1 - Brandt, A. A1 - Ebbe, B. A1 - Gooday, A.J. Y1 - 2007/// N2 - The multidisciplinary international project ANDEEP (Antarctic deep-sea benthic biodiversity: colonisation history and recent community patterns) involved a two-leg expedition to the Weddelland Scotia seas in 2002 and a third expedition in 2005 to the Cape and Agulhas basins, Weddell Sea, Bellingshausen Sea and Drake Passage (Fig. 1). In 2004, we published the first results, based on the material collected during ANDEEP I/II (Brandt and Hilbig, 2004). This second volume concerns work done since 2004, including results based on material obtained during ANDEEP III. These three expeditions yielded a very rich and unique collection of material and data. Much work remains to be done and publications will continue to appear in the literature for many years to come. However, the end of the directly funded phase of the project provides a good opportunity to revisit the original questions that we had hoped to answer, to determine our success in doing so, and to define remaining gaps in our knowledge of the deep Southern Ocean faunas. Generally, the goals that were set for ANDEEP have been reached. In particular, there has been an increase in our knowledge of the scale and patterns of species diversity in the deep ocean and an improved understanding of the origins of the abyssal fauna of the Southern Ocean. Many of the remaining gaps have emerged from the knowledge we gained and thus are part of the success of the project rather than an indication of failure. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 54 KW - Southern Ocean KW - Deep sea KW - Biodiversity KW - Meiofauna KW - Makrofauna KW - Megafauna SN - 0967-0645 TI - Introduction to ANDEEP, summary and outlook SP - 1645 AV - none EP - 1651 ER - TY - JOUR ID - soton356885 UR - https://eprints.soton.ac.uk/356885/ IS - 8 A1 - Brannigan, Liam A1 - Lenn, Yueng-Djern A1 - Rippeth, Tom P. A1 - McDonagh, Elaine A1 - Chereskin, Teresa K. A1 - Sprintall, Janet Y1 - 2013/08// N2 - Observations are used to evaluate a simple theoretical model for the generation of near-inertial shear spikes at the base of the open ocean mixed layer when the upper ocean displays a two-layer structure. The model predicts that large changes in shear squared can be produced by the alignment of the wind and shear vectors. A climatology of stratification and shear variance in Drake Passage is presented, which shows that these assumptions are most applicable to summer, fall, and spring but are not highly applicable to winter. Temperature, salinity, and velocity data from a high spatial resolution cruise in Drake Passage show that the model does not predict all large changes in shear variance; the model is most effective at predicting changes in shear squared when it arises owing to near-inertial wind-driven currents without requiring a rotating resonant wind stress. The model is also more effective where there is a uniform mixed layer above a strongly stratified transition layer. Rotary spectral and statistical analysis of an additional 242 Drake Passage transects from 1999 to 2011 confirmed the presence of this shear-spiking mechanism, particularly in summer, spring, and fall when stratification is stronger. JF - Journal of Physical Oceanography VL - 43 KW - Southern Ocean KW - Atmosphere-ocean interaction KW - Diapycnal mixing KW - Shear structure/flows KW - Oceanic mixed layer KW - Kelvin-Helmholtz instabilities SN - 0022-3670 TI - Shear at the Base of the Oceanic Mixed Layer Generated by Wind Shear Alignment SP - 1798 AV - none EP - 1810 ER - TY - JOUR ID - soton354488 UR - https://eprints.soton.ac.uk/354488/ IS - 1 A1 - Brearley, J. Alexander A1 - Sheen, Katy L. A1 - Naveira Garabato, Alberto C. A1 - Smeed, David A. A1 - Speer, Kevin G. A1 - Thurnherr, Andeaus M. A1 - Meredith, Michael M. A1 - Waterman, Stephanie N. Y1 - 2014/01/16/ N2 - The fate of a deep boundary current that originates in the Southeast Pacific and flows southward along the continental slope of South America is elucidated. The current transports poorly ventilated water of low salinity (a type of Pacific Deep Water; PDW), into Drake Passage. East of Drake Passage, the boundary current breaks into fresh anticyclonic eddies, nine examples of which were observed in mooring data from December 2009 to March 2012. The observed eddies appear to originate mainly from a topographic separation point close to 60°W, have typical diameters of 20?60?km and accompanying Rossby numbers of 0.1?0.3. These features are likely to be responsible for transporting PDW meridionally across the ACC, explaining the near-homogenization of Circumpolar Deep Water properties downstream of Drake Passage. This mechanism of boundary current breakdown may constitute an important process in the Southern Ocean overturning circulation. JF - Geophysical Research Letters VL - 41 KW - Boundary currents KW - Eddies KW - Overturning KW - Southern Ocean SN - 0094-8276 TI - Deep boundary current disintegration in Drake Passage SP - 121 AV - public EP - 127 ER - TY - JOUR ID - soton374633 UR - https://eprints.soton.ac.uk/374633/ IS - 3 A1 - Brown, Peter J. A1 - Jullion, Loïc A1 - Landschützer, Peter A1 - Bakker, Dorothee C.E. A1 - Naveira Garabato, Alberto C. A1 - Meredith, Michael P. A1 - Torres-Valdés, Sinhué A1 - Watson, Andrew A1 - Hoppema, Mario A1 - Loose, Brice A1 - Jones, Elizabeth M. A1 - Telszewski, Maciej A1 - Jones, Steve D. A1 - Wanninkhof, Rik Y1 - 2015/03// N2 - The accumulation of carbon within the Weddell Gyre, and its exchanges across the gyre boundaries are investigated with three recent full-depth oceanographic sections enclosing this climatically-important region. The combination of carbon measurements with ocean circulation transport estimates from a box inverse analysis reveal that deep water transports associated with Warm Deep Water (WDW) and Weddell Sea Deep Water dominate the gyre's carbon budget, while a dual-cell vertical overturning circulation leads to both upwelling and the delivery of large quantities of carbon to the deep ocean. Historical sea surface pCO2 observations, interpolated using a neural network technique, confirm the net summertime sink of 0.044 to 0.058 ± 0.010 Pg C yr-1 derived from the inversion. However, a wintertime outgassing signal similar in size results in a statistically insignificant annual air-to-sea CO2 flux of 0.002 ± 0.007 Pg C yr-1 (mean 1998-2011) to 0.012 ± 0.024 Pg C yr-1 (mean 2008-2010) to be diagnosed for the Weddell Gyre. A surface layer carbon balance, independently derived from in situ biogeochemical measurements reveals that freshwater inputs and biological drawdown decrease surface ocean inorganic carbon levels more than they are increased by WDW entrainment, resulting in an estimated annual carbon sink of 0.033 ± 0.021 Pg C yr-1. Although relatively less efficient for carbon uptake than the global oceans, the summertime Weddell Gyre suppresses the winter outgassing signal, while its biological pump and deep water formation act as key conduits for transporting natural and anthropogenic carbon to the deep ocean where they can reside for long timescales. JF - Global Biogeochemical Cycles VL - 29 KW - Southern Ocean KW - Weddell Gyre KW - ocean carbon cycle KW - neural network KW - air-sea exchange of CO2 KW - observations SN - 0886-6236 TI - Carbon dynamics of the Weddell Gyre, Southern Ocean SP - 288 AV - public EP - 306 ER - TY - JOUR ID - soton364341 UR - https://eprints.soton.ac.uk/364341/ IS - 8 A1 - Browning, T.J. A1 - Bouman, H.A. A1 - Henderson, G.M. A1 - Mather, T.A. A1 - Pyle, D.M. A1 - Schlosser, C. A1 - Woodward, E.M.S. A1 - Moore, C.M. Y1 - 2014/04/28/ N2 - Volcanic eruptions have been hypothesized as an iron supply mechanism for phytoplankton blooms; however, little direct evidence of stimulatory responses has been obtained in the field. Here we present the results of twenty-one 1?2?day bottle enrichment experiments from cruises in the South Atlantic and Southern Ocean which conclusively demonstrated a photophysiological and biomass stimulation of phytoplankton communities following supply of basaltic or rhyolitic volcanic ash. Furthermore, experiments in the Southern Ocean demonstrated significant phytoplankton community responses to volcanic ash supply in the absence of responses to addition of dissolved iron alone. At these sites, dissolved manganese concentrations were among the lowest ever measured in seawater, and we therefore suggest that the enhanced response to ash may have been a result of the relief of manganese (co)limitation. Our results imply that volcanic ash deposition events could trigger extensive phytoplankton blooms, potentially capable of significant impacts on regional carbon cycling. JF - Geophysical Research Letters VL - 41 KW - iron fertilization KW - volcanic ash KW - Southern Ocean KW - colimitation KW - manganese KW - phytoplankton SN - 0094-8276 TI - Strong responses of Southern Ocean phytoplankton communities to volcanic ash SP - 2851 AV - public EP - 2857 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 - soton455503 UR - https://eprints.soton.ac.uk/455503/ IS - 1 A1 - Carpenter-Kling, Tegan A1 - Pistorius, Pierre A1 - Reisinger, Ryan A1 - Cherel, Yves A1 - Connan, Maëlle Y1 - 2020/06/29/ N2 -Background: Precise and accurate retrospective geolocation of marine predators via their tissues' isotopic composition relies on quality reference maps of relevant isotopic gradients ("isoscapes"). Additionally, a good working knowledge of any discrimination factors that may offset a marine predator's isotopic composition from baseline isotopic values, as well as tissue specific retention rates, are imperative. We provide a critical assessment of inter-specific differences among marine predator-level isoscapes within the Indian Sector of the Southern Ocean. Methods: We combined fine-scale GPS tracking data and concurrent blood plasma ?13C and ?15N values of eight seabird species (three albatross, two giant petrel and three penguin species) breeding at Marion Island to produce species- and guild-specific isoscapes. Results: Overall, our study revealed latitudinal spatial gradients in both ?13C and ?15N for far-ranging seabirds (albatrosses and giant petrels) as well as inshore-offshore gradients for near-ranging seabirds (penguins). However, at the species level, latitudinal spatial gradients were not reflected in the ?13C and ?15N isoscapes of two and three, respectively, of the five far-ranging species studied. It is therefore important when possible to estimate and apply species-specific isoscapes or have a good understanding of any factors and pathways affecting marine predators' isotopic composition when estimating the foraging distribution of marine predators via their tissues' stable isotope compositions. Conclusions: Using a multi-species approach, we provide evidence of large and regional scale systematic spatial variability of ?13C and ?15N at the base of the marine food web that propagates through trophic levels and is reflected in the isotopic composition of top predators' tissues.
JF - Movement Ecology VL - 8 KW - Geolocation KW - Penguins KW - Procellariiformes KW - Seabirds KW - Southern Ocean KW - Stable isotope ecology TI - A critical assessment of marine predator isoscapes within the southern Indian Ocean AV - public ER - TY - JOUR ID - soton455502 UR - https://eprints.soton.ac.uk/455502/ IS - 20 A1 - Carpenter-Kling, Tegan A1 - Reisinger, Ryan R. A1 - Orgeret, Florian A1 - Connan, Maëlle A1 - Stevens, Kim L. A1 - Ryan, Peter G. A1 - Makhado, Azwianewi A1 - Pistorius, Pierre A. N2 -Seasonal and annual climate variations are linked to fluctuations in the abundance and distribution of resources, posing a significant challenge to animals that need to adjust their foraging behavior accordingly. Particularly during adverse conditions, and while energetically constrained when breeding, animals ideally need to be flexible in their foraging behavior. Such behavioral plasticity may separate ?winners? from ?losers? in light of rapid environmental changes due to climate change. Here, the foraging behavior of four sub-Antarctic albatross species was investigated from 2015/16 to 2017/18, a period characterized by pronounced environmental variability. Over three breeding seasons on Marion Island, Prince Edward Archipelago, incubating wandering (WA, Diomedea exulans; n = 45), grey-headed (GHA, Thalassarche chrysostoma; n = 26), sooty (SA, Phoebetria fusca; n = 23), and light-mantled (LMSA, P. palpebrata; n = 22) albatrosses were tracked with GPS loggers. The response of birds to environmental variability was investigated by quantifying interannual changes in their foraging behavior along two axes: spatial distribution, using kernel density analysis, and foraging habitat preference, using generalized additive mixed models and Bayesian mixed models. All four species were shown to respond behaviorally to environmental variability, but with substantial differences in their foraging strategies. WA was most general in its habitat use defined by sea surface height, eddy kinetic energy, wind speed, ocean floor slope, and sea-level anomaly, with individuals foraging in a range of habitats. In contrast, the three smaller albatrosses exploited two main foraging habitats, with habitat use varying between years. Generalist habitat use by WA and interannually variable use of habitats by GHA, SA, and LMSA would likely offer these species some resilience to predicted changes in climate such as warming seas and strengthening of westerly winds. However, future investigations need to consider other life-history stages coupled with demographic studies, to better understand the link between behavioral plasticity and population responses.
VL - 10 TI - Foraging in a dynamic environment: Response of four sympatric sub-Antarctic albatross species to interannual environmental variability AV - public EP - 11295 N1 - Funding Information: We thank all field personnel who spent many long hours assisting with the deployment of GPS dataloggers. A special mention goes to Stefan Schoombie, Janine Schoombie, Jessie Berndt, Albert Snyman, Makhudu Masotla and David Green without whose dedication and excellent fieldwork this study would not have been possible. Research on Marion Island is made possible through the logistical support from South Africa's Department of Environment, Forestry, and Fisheries. Financial support was received from the South Africa's National Research Foundation (NRF), through its South African National Antarctic Programme, as a grant to Pierre Pistorius (grant number SNA093071) and Ryan Reisinger was the recipient of a NRF postdoctoral grant (SANCOR grant 94916). We thank the associate editor and reviewers for their comments. Funding Information: We thank all field personnel who spent many long hours assisting with the deployment of GPS dataloggers. A special mention goes to Stefan Schoombie, Janine Schoombie, Jessie Berndt, Albert Snyman, Makhudu Masotla and David Green without whose dedication and excellent fieldwork this study would not have been possible. Research on Marion Island is made possible through the logistical support from South Africa's Department of Environment, Forestry, and Fisheries. Financial support was received from the South Africa's National Research Foundation (NRF), through its South African National Antarctic Programme, as a grant to Pierre Pistorius (grant number SNA093071) and Ryan Reisinger was the recipient of a NRF postdoctoral grant (SANCOR grant 94916). We thank the associate editor and reviewers for their comments. Publisher Copyright: © 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. Copyright: Copyright 2020 Elsevier B.V., All rights reserved. Y1 - 2020/10/01/ JF - Ecology and Evolution KW - behavioral plasticity KW - biologging KW - central place foragers KW - marine predators KW - resilience KW - Southern Annual Mode SN - 2045-7758 SP - 11277 ER - TY - JOUR ID - soton360798 UR - https://eprints.soton.ac.uk/360798/ IS - 10 A1 - Castrillejo, Maxi A1 - Statham, Peter J. A1 - Fones, Gary R. A1 - Planquette, Hélène A1 - Idrus, Farah A1 - Roberts, Keiron Y1 - 2013/10// N2 - A phytoplankton bloom shown to be naturally iron (Fe) induced occurs north of the Crozet Islands (Southern Ocean) every year, providing an ideal opportunity to study dissolved trace metal distributions within an island system located in a high nutrient low chlorophyll (HNLC) region. We present water column profiles of dissolved nickel (Ni), zinc (Zn), cobalt (Co), cadmium (Cd), lead (Pb), aluminium (Al), and manganese (Mn) obtained as part of the NERC CROZEX program during austral summer (2004?2005). Two stations (M3 and M1) were sampled downstream (north) of Crozet in the bloom area and near the islands, along with a control station (M2) in the HNLC zone upstream (south) of the islands. The general range found was for Ni, 4.64?6.31 nM; Zn, 1.59?7.75 nM; Co, 24?49 pM; Cd, 135?673 pM; Pb, 6?22 pM; Al, 0.13?2.15 nM; and Mn, 0.07?0.64 nM. Vertical profiles indicate little island influence to the south with values in the range of other trace metal deprived regions of the Southern Ocean. Significant removal of Ni and Cd was observed in the bloom and Zn was moderately correlated with reactive silicate (Si) indicating diatom control over the internal cycling of this metal. Higher concentrations of Zn and Cd were observed near the islands. Pb, Al, and Mn distributions also suggest small but significant atmospheric dust supply particularly in the northern region. JF - Journal of Geophysical Research: Oceans VL - 118 KW - Southern Ocean KW - trace metals KW - biogeochemical cycles KW - iron fertilization SN - 2169-9275 TI - Dissolved trace metals (Ni, Zn, Co, Cd, Pb, Al, and Mn) around the Crozet Islands, Southern Ocean SP - 5188 AV - none EP - 5201 ER - TY - RPRT ID - soton19316 UR - https://eprints.soton.ac.uk/19316/ Y1 - 2005/10// PB - International CLIVAR Project Office T3 - No. 35 (Vol. 10(4)) KW - CLIVAR KW - WCRP KW - Exchanges KW - newsletter KW - Southern Hemisphere Climate Variability ED - Cattle, H. ED - Sparrow, M. M1 - project_report TI - CLIVAR Exchanges No. 35. Southern Hemisphere Climate Variability AV - public EP - 76 ER - TY - JOUR N1 - This work was supported by the Natural Environmental Research Council [grant number NE/L002531/1] and contributes to British Antarctic Survey's ?Polar Science for Planet Earth? program. ID - soton453162 UR - https://eprints.soton.ac.uk/453162/ A1 - Chadwick, M. A1 - Allen, C.s. A1 - Sime, L.c. A1 - Crosta, X. A1 - Hillenbrand, C.-d. Y1 - 2022/01// N2 -Marine Isotope Stage (MIS) 5e (130?116 ka) represents an important ?process analogue? for understanding the climatic feedbacks and responses likely active under future anthropogenic warming. Reconstructing the Southern Ocean (SO) palaeoenvironment during MIS 5e and comparing it to the present day provides insights into the different responses of the SO sectors to a warmer climate. This study presents new records from seven marine sediment cores for MIS 5e together with their surface sediment records; all cores are located south of 55 oS. We investigate changes in diatom species assemblage and the accompanying variations in sea surface temperatures, winter sea-ice extent (WSIE) and glacial meltwater flux. All records show warmer conditions and a reduced WSIE during MIS 5e relative to the surface sediments. While the Pacific and Indian Sector records present very stable conditions throughout MIS 5e, the Atlantic Sector records display much more changeable conditions, particularly with respect to the WSIE. These variable conditions are attributed to higher iceberg and glacial meltwater flux in the Weddell Sea. This evidence for increased iceberg and glacial meltwater flux in the Weddell Sea during MIS 5e may have significant implications for understanding the stability of the West Antarctic Ice Sheet, both during MIS 5e and under future warming.
JF - Marine Micropaleontology VL - 170 KW - Diatom KW - MIS 5e KW - Marine Sediment Core KW - Palaeoenvironment KW - Southern Ocean SN - 0377-8398 TI - How does the Southern Ocean palaeoenvironment during Marine Isotope Stage 5e compare to the modern? AV - public ER - TY - JOUR ID - soton440895 UR - https://eprints.soton.ac.uk/440895/ A1 - Chadwick, M. A1 - Allen, C.s. A1 - Sime, L.c. A1 - Hillenbrand, C.-d. Y1 - 2020/02/01/ N2 - The peak of the Last Interglacial, Marine Isotope Stage (MIS) 5e (130?116 ka), provides a valuable ?process analogue? for validating the climatic feedbacks and forcings likely active under future anthropogenic warming. Reconstructing exact timings of MIS 5e peak warming and minimum winter sea-ice extent (WSIE) throughout the Southern Ocean (SO) will help to identify the interactions and feedbacks within the ice-ocean system. Here we present a new MIS 5e marine sediment record from the SW Atlantic sector together with 28 published core records (chronologies standardised to the LR04 ?18O benthic stack; Lisiecki and Raymo, 2005) to investigate the timing and sequence of minimum WSIE and peak warming across the SO. Sea-surface temperatures (SSTs) peaked earliest in the Indian (20oE?150oE) and Atlantic (70oW?20oE) sectors, at 128.7 ± 0.8 ka and 127.4 ± 1.1 ka respectively, followed by the Pacific sector (150oE?70oW) at 124.9 ± 3.6 ka. The interval of minimum WSIE for all three sectors occurred within the period from 129?125 ka, consistent with the ?128 ka sea salt flux minimum in Antarctic ice cores. Minimum WSIE appears to have coincided with peak July insolation at 55 oS, suggesting it could be linked with the mildest winters. The reduced WSIE during MIS 5e would have likely reduced the production of deep- and bottom water masses, inhibiting storage of CO2 in the abyssal ocean and lowering nutrient availability in SO surface waters. Examining a wide spatial range of proxy records for MIS 5e is a critical step forward in understanding climatic interactions and processes that will be active under warmer global temperatures. JF - Quaternary Science Reviews VL - 229 KW - Interglacial KW - Palaeoceanography KW - Sediment cores KW - Southern Ocean SN - 0277-3791 TI - Analysing the timing of peak warming and minimum winter sea-ice extent in the Southern Ocean during MIS 5e AV - public ER - TY - JOUR ID - soton42479 UR - https://eprints.soton.ac.uk/42479/ IS - 18-20 A1 - Charette, M.A. A1 - Gonneea, M.E. A1 - Morris, P.J. A1 - Statham, P. A1 - Fones, G. A1 - Planquette, H. A1 - Salter, I. A1 - Naveira Garabato, A.C. Y1 - 2007/// N2 - Elevated levels of productivity in the wake of Southern Ocean island systems are common despite the fact that they are encircled by high-nutrient low-chlorophyll (HNLC) waters. In the Crozet Plateau region, it has been hypothesized that iron from island runoff or sediments of the plateau could be fueling the austral summer phytoplankton bloom. Here, we use radium isotopes to quantify the rates of surface-ocean iron supply fueling the bloom in the Crozet Plateau region. A 1-D eddy-diffusion-mixing model applied to a 228Ra profile (t1/2=5.75 years) at a station north of the islands suggests fast vertical mixing in the upper 300 m (Kz=11?100 cm2 s?1) with slower mixing between 300 and 1000 m (Kz=1.5 cm2 s?1). This estimate is discussed in the context of Kz derived from the CTD/LADCP data. In combination with the dissolved Fe profile at this location, we estimated a vertical flux of between 5.6 and 31 nmol Fe m?2 d?1. The cross-plateau gradients in the short-lived radium isotopes, 224Ra (t1/2=3.66 d) and 223Ra (t1/2=11.4 d), yielded horizontal eddy diffusivities (Kh) of 39 and 6.6 m2 s?1, respectively. If we assume that the islands (surface runoff) alone were supplying dissolved Fe to the bloom region, then the flux estimates range from 2.3 to 14 nmol Fe m?2 d?1. If the plateau sediments are considered a source of Fe, and conveyed to the bloom region through deep winter mixing combined with horizontal transport, then this flux may be as high as 64?390 nmol Fe m?2 d?1. Combined, these Fe sources are sufficient to initiate and maintain the annual phytoplankton bloom. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 54 KW - Radium isotopes KW - Iron KW - Productivity KW - Ocean mixing KW - Southern Ocean SN - 0967-0645 TI - Radium isotopes as tracers of iron sources fueling a Southern Ocean phytoplankton bloom SP - 1989 AV - none EP - 1998 ER - TY - JOUR ID - soton384870 UR - https://eprints.soton.ac.uk/384870/ IS - 2 A1 - Chen, Chong A1 - Linse, Katrin A1 - Roterman, Christopher N. A1 - Copley, Jonathan T. A1 - Rogers, Alex D. Y1 - 2015/10// N2 - Recently discovered hydrothermal vent fields on the East Scotia Ridge (ESR, 56?60°S, 30°W), Southern Ocean, and the South West Indian Ridge (SWIR, 37°S 49°E), Indian Ocean, host two closely related new species of peltospirid gastropods. Morphological and molecular (mitochondrial cytochrome c oxidase subunit I, COI) characterization justify the erection of Gigantopelta gen. nov. within the Peltospiroidae with two new species, Gigantopelta chessoia sp. nov. from ESR and Gigantopelta aegis sp. nov. from SWIR. They attain an extremely large size for the clade Neomphalina, reaching 45.7?mm in shell diameter. The oesophageal gland of both species is markedly enlarged. Gigantopelta aegis has a thick sulphide coating on both the shell and the operculum of unknown function. The analysis of a 579-bp fragment of the COI gene resulted in 19?28% pairwise distance between Gigantopelta and six other genera in Peltospiridae, whereas the range amongst those six genera was 12?28%. The COI divergence between the two newly described species of Gigantopelta was 4.43%. Population genetics analyses using COI (370?bp) of 30 individuals of each species confirmed their genetic isolation and indicate recent rapid demographic expansion in both species.The Prince Gustav Channel is a narrow seaway located in the western Weddell Sea on the northeastern-most tip of the Antarctic Peninsula. The channel is notable for both its deep (>1200 m) basins, and a dynamic glacial history that most recently includes the break-up of the Prince Gustav Ice Shelf, which covered the southern portion of the channel until its collapse in 1995. However, the channel remains mostly unsampled, with very little known about its benthic biology. We present a preliminary account of the benthic annelid fauna of the Prince Gustav Channel in addition to samples from Duse Bay, a sheltered, glacier-influenced embayment in the northwestern portion of the channel. Samples were collected using an Agassiz Trawl, targeting megafaunal and large macrofaunal sized animals at depths ranging between 200?1200 m; the seafloor and associated fauna were also documented in situ using a Shallow Underwater Camera System (SUCS). Sample sites varied in terms of depth, substrate type, and current regime, and communities were locally variable across sites in terms of richness, abundance, and both taxonomic and functional composition. The most diverse family included the motile predator/scavenger Polynoidae, with 105 individuals in at least 12 morphospecies, primarily from a single site. This study provides first insights into diverse and spatially heterogeneous benthic communities in a dynamic habitat with continuing glacial influence, filling sampling gaps in a poorly studied region of the Southern Ocean at direct risk from climate change. These specimens will also be utilized in future molecular investigations, both in terms of describing the genetic biodiversity of this site and as part of wider phylogeographic and population genetic analyses assessing the connectivity, evolutionary origins, and demographic history of annelid fauna in the region.
JF - Frontiers in Marine Science VL - 7 KW - benthic KW - morphology KW - polychaeta KW - Southern Ocean KW - species checklist KW - taxonomy KW - Weddell Sea SN - 2296-7745 TI - Annelid Fauna of the Prince Gustav Channel, a Previously Ice-Covered Seaway on the Northeastern Antarctic Peninsula AV - public EP - 19 ER - TY - GEN ID - soton487238 UR - https://eprints.soton.ac.uk/487238/ A1 - Drennan, Regan A1 - Glover, Adrian G A1 - Copley, Jon A1 - Linse, Katrin A1 - Dahlgren, Thomas G A1 - Taboada, Sergio A1 - Arias, Maria Belen Y1 - 2024/// N2 - Data supporting University of Southampton Doctoral Thesis entitled: Patterns of diversity, connectivity, and evolution in southern ocean and deep-sea annelids (2024) by Regan Drennan See README for detail of each dataset. Data includes genomic data (Single Nucleotide Polymorphism (SNP) catalogs), held externally on ZENODO due to file size (DOI: 10.5281/zenodo.10606641). PB - University of Southampton KW - ddRADseq KW - population genomics KW - Annelida KW - Antarctica KW - biodiversity KW - Southern Ocean KW - Deep Sea KW - Deep-sea mining KW - population genetics KW - species delimitation KW - Polychaeta KW - DNA barcoding TI - Data supporting University of Southampton Doctoral Thesis entitled: Patterns of diversity, connectivity, and evolution in southern ocean and deep-sea annelids AV - public ER - TY - JOUR ID - soton367638 UR - https://eprints.soton.ac.uk/367638/ A1 - Duffy, Grant A. A1 - Lundsten, Lonny A1 - Kuhnz, Linda A. A1 - Paull, Charles K. Y1 - 2014/06// N2 - Remotely operated vehicle surveys were conducted in five submarine canyons off Southern California during research expeditions in 2005 and 2010. Video transects from a range of depths were analysed to produce presence/absence data of megafauna for each site. A comparison of benthic communities at various depths, locales, and canyons was performed. No significant difference was found between canyon communities based on the level of sediment transport activity, however this may be due to the unbalanced sampling of this opportunistic study. There was significant variation in biological community composition and abundance amongst water depths. These depth-related trends are in agreement with the findings of the previous studies and are likely tied to depth-correlated variables such as hydrostatic pressure, temperature, salinity, and oxygen concentration. Species richness was found to initially increase with depth before declining rapidly at the mouths of the studied canyons. Low oxygen levels in the Santa Monica Basin, into which four of the surveyed canyons empty, may explain this. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 104 KW - Community composition KW - Deep sea KW - Hueneme KW - La Jolla KW - Mugu KW - Redondo KW - ROVs KW - Santa Monica KW - Southern California KW - Submarine canyons SN - 0967-0645 TI - A comparison of megafaunal communities in five submarine canyons off Southern California, USA SP - 259 AV - none EP - 266 ER - TY - JOUR ID - soton63081 UR - http://www.agu.org/pubs/crossref/2008/2007JC004351.shtml IS - C7 A1 - Döös, K. A1 - Nycander, J. A1 - Coward, A.C. Y1 - 2008/07/22/ N2 - The meridional overturning cells in the Southern Ocean are decomposed by Lagrangian tracing using velocity and density fields simulated with an ocean general circulation model. Particular emphasis is given to the Deacon Cell. The flow is divided into four major components: (1) water circling around Antarctica in the Antarctic Circumpolar Current (ACC), (2) water leaving the ACC toward the north into the three world oceans, (3) water coming from the north and joining the ACC, mainly consisting of North Atlantic Deep Water (NADW), and (4) interocean exchange between the three world oceans without circling around Antarctica. The Deacon Cell has an amplitude of 20 Sv, of which 6 Sv can be explained by the east-west tilt of the ACC, 5 Sv by the east-west tilt of the subtropical gyre, and the remaining 9 Sv by the differences of the slope and depth of the southward transport of NADW and its return flow as less dense water. The diabatic or cross-isopycnal Deacon Cell is only 2 Sv. JF - Journal of Geophysical Research VL - 113 KW - Deacon Cell KW - Southern Ocean KW - Lagrangian trajectories SN - 0148-0227 TI - Lagrangian decomposition of the Deacon Cell AV - none ER - TY - JOUR ID - soton367440 UR - https://eprints.soton.ac.uk/367440/ A1 - Ebersbach, Friederike A1 - Assmy, Philipp A1 - Martin, Patrick A1 - Schulz, Isabelle A1 - Wolzenburg, Sina A1 - Nöthig, Eva-Maria Y1 - 2014/07// N2 - The taxonomic composition and types of particles comprising the downward particle flux were examined during the mesoscale artificial iron fertilisation experiment LOHAFEX. The experiment was conducted in low-silicate waters of the Atlantic Sector of the Southern Ocean during austral summer (January?March 2009), and induced a bloom dominated by small flagellates. Downward particle flux was low throughout the experiment, and not enhanced by addition of iron; neutrally buoyant sediment traps contained mostly faecal pellets and faecal material apparently reprocessed by mesozooplankton. TEP fluxes were low, ?5 mg GX eq. m?2 d?1, and a few phytodetrital aggregates were found in the sediment traps. Only a few per cent of the POC flux was found in the traps consisting of intact protist plankton, although remains of taxa with hard body parts (diatoms, tintinnids, thecate dinoflagellates and foraminifera) were numerous, far more so than intact specimens of these taxa. Nevertheless, many small flagellates and coccoid cells, belonging to the pico- and nanoplankton, were found in the traps, and these small, soft-bodied cells probably contributed the majority of downward POC flux via mesozooplankton grazing and faecal pellet export. TEP likely played an important role by aggregating these small cells, and making them more readily available to mesozooplankton grazers. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 89 KW - Nano- and picoplankton KW - Export flux KW - Iron fertilisation KW - Protists KW - Sediment trap KW - Southern Ocean SN - 0967-0637 TI - Particle flux characterisation and sedimentation patterns of protistan plankton during the iron fertilisation experiment LOHAFEX in the Southern Ocean SP - 94 AV - public EP - 103 ER - TY - GEN ID - soton445093 UR - https://eprints.soton.ac.uk/445093/ A1 - Edwards, Rosalind A1 - Moewaka Barnes, Helen A1 - McGregor, Deborah A1 - Brannelly, Tula Y1 - 2020/12/04/ N2 - This commentary discusses the framing of the production of a series of online text-based and visual resources aimed at researchers embarking on Indigenous and non-Indigenous research partnerships, and in particular supporting non-Indigenous researchers to think about our/their methods, assumptions and behaviour. We identify the tension in mainstream funding for such partnerships, and discuss the implications of Northern epistemological claims to agendas and universality as against Southern epistemologies acknowledging diversity and challenging oppressions. We note the distinct bases for Indigenous methodologies. Our commentary outlines and illustrates the online downloadable resources produced by our own Indigenous and non-Indigenous research partnership, including a video/audio recording, a comic, and blog posts, addressing decolonized collaborative practice. KW - Indigenous and non-Indigenous research partnerships; Northern epistemology; Southern epistemologies; Indigenous methodologies; decolonized collaborative practice SN - 1052-0147 TI - Supporting indigenous and non-indigenous research partnerships SP - 6 AV - public EP - 15 ER - TY - JOUR ID - soton49681 UR - http://www.springerlink.com/content/q1456g1830276252/?p=ca87304489db422c893f85b7fb06f6a8&pi=14 IS - 7 A1 - Esteban, G.F. A1 - Gooday, A.J. A1 - Clarke, K.J. Y1 - 2007/06// N2 - The world of protists remains largely unexplored. A thorough electron-microscopic investigation of a few microlitres of deep-sea sediment from 2,964 m water depth near the South Sandwich Islands (Southern Ocean) revealed siliceous scales of filose-amoeba protist species, two of which have not been reported previously from Antarctica or from elsewhere in the Southern Hemisphere. However, all the species are known from other oceans and, in one case, from freshwater habitats. The Antarctic protistan scales belong to four species of filose amoebae: Pinaciophora fluviatilis Greef 1869, Pinaciophora denticulata Thomsen 1978, Pinaciophora multicosta Thomsen 1978 and Rabdiaster reticulata (Thomsen 1979) Mikrjukov 1999 nov. comb. Our study shows that (1) none of the species has been recorded from the Australasian biogeograpical region, (2) Pinaciophora multicosta and Rabdiaster reticulata are new records for the Southern Ocean and for the Southern Hemisphere as a whole, (3) prior to this investigation, Pinaciophora multicosta had been reported once only, from the Baltic Sea (Europe). These results highlight the problem of undersampling in the study of the global distribution of protists. JF - Polar Biology VL - 30 KW - Antarctica KW - Biogeography KW - Heliozoa KW - Scale-bearing protists KW - South Sandwich Islands KW - Southern Hemisphere SN - 0722-4060 TI - Siliceous scales of filose-amoebae (Pompholyxophryidae, Rotosphaerida) from deep Southern Ocean sediments, including first records for the Southern Hemisphere SP - 945 AV - none EP - 950 ER - TY - JOUR ID - soton372139 UR - https://eprints.soton.ac.uk/372139/ IS - 11 A1 - Evans, Dafydd Gwyn A1 - Zika, Jan D. A1 - Naveira Garabato, Alberto C. A1 - Nurser, A.J. George Y1 - 2014/11// N2 - Seasonal changes in water mass properties are discussed in thermohaline coordinates from a seasonal climatology and repeat hydrographic sections. The SR1b CTD transects along Drake Passage are used as a case study. The amount of water within temperature and salinity classes and changes therein are used to estimate dia-thermal and dia-haline transformations. These transformations are considered in combination with climatologies of surface buoyancy flux to determine the relative contributions of surface buoyancy fluxes and subsurface mixing to changes in the distribution of water in thermohaline coordinates. The framework developed provides unique insights into the thermohaline circulation of the water masses that are present within Drake Passage, including the erosion of Antarctic Winter Water (AAWW) during the summer months and the interaction between the Circumpolar Deep Waters (CDW) and Antarctic Intermediate Water (AAIW). The results presented are consistent with summertime wind-driven inflation of the CDW layer and deflation of the AAIW layer, and with new AAIW produced in the winter as a mixture of CDW, remnant AAWW, and surface waters. This analysis therefore highlights the role of surface buoyancy fluxes in the Southern Ocean overturning. JF - Journal of Geophysical Research VL - 119 KW - southern ocean overturning KW - drake passage KW - water masses KW - thermohaline coordinates KW - in situ observations SN - 0148-0227 TI - The imprint of Southern Ocean overturning on seasonal water mass variability in Drake Passage SP - 7987 AV - public EP - 8010 ER - TY - JOUR ID - soton381303 UR - https://eprints.soton.ac.uk/381303/ A1 - Farneti, Riccardo A1 - Downes, Stephanie M. A1 - Griffies, Stephen M. A1 - Marsland, Simon J. A1 - Behrens, Erik A1 - Bentsen, Mats A1 - Bi, Daohua A1 - Biastoch, Arne A1 - Böning, Claus A1 - Bozec, Alexandra A1 - Canuto, Vittorio M. A1 - Chassignet, Eric A1 - Danabasoglu, Gokhan A1 - Danilov, Sergey A1 - Diansky, Nikolay A1 - Drange, Helge A1 - Fogli, Pier Giuseppe A1 - Gusev, Anatoly A1 - Hallberg, Robert W. A1 - Howard, Armando A1 - Ilicak, Mehmet A1 - Jung, Thomas A1 - Kelley, Maxwell A1 - Large, William G. A1 - Leboissetier, Anthony A1 - Long, Matthew A1 - Lu, Jianhua A1 - Masina, Simona A1 - Mishra, Akhilesh A1 - Navarra, Antonio A1 - Nurser, A.J. George A1 - Patara, Lavinia A1 - Samuels, Bonita L. A1 - Sidorenko, Dmitry A1 - Tsujino, Hiroyuki A1 - Uotila, Petteri A1 - Wang, Qiang A1 - Yeager, Steve G. Y1 - 2015/09// N2 - In the framework of the second phase of the Coordinated Ocean-ice Reference Experiments (CORE-II), we present an analysis of the representation of the Antarctic Circumpolar Current (ACC) and Southern Ocean meridional overturning circulation (MOC) in a suite of seventeen global ocean?sea ice models. We focus on the mean, variability and trends of both the ACC and MOC over the 1958?2007 period, and discuss their relationship with the surface forcing. We aim to quantify the degree of eddy saturation and eddy compensation in the models participating in CORE-II, and compare our results with available observations, previous fine-resolution numerical studies and theoretical constraints. Most models show weak ACC transport sensitivity to changes in forcing during the past five decades, and they can be considered to be in an eddy saturated regime. Larger contrasts arise when considering MOC trends, with a majority of models exhibiting significant strengthening of the MOC during the late 20th and early 21st century. Only a few models show a relatively small sensitivity to forcing changes, responding with an intensified eddy-induced circulation that provides some degree of eddy compensation, while still showing considerable decadal trends. Both ACC and MOC interannual variabilities are largely controlled by the Southern Annular Mode (SAM). Based on these results, models are clustered into two groups. Models with constant or two-dimensional (horizontal) specification of the eddy-induced advection coefficient ? show larger ocean interior decadal trends, larger ACC transport decadal trends and no eddy compensation in the MOC. Eddy-permitting models or models with a three-dimensional time varying ? show smaller changes in isopycnal slopes and associated ACC trends, and partial eddy compensation. As previously argued, a constant in time or space ? is responsible for a poor representation of mesoscale eddy effects and cannot properly simulate the sensitivity of the ACC and MOC to changing surface forcing. Evidence is given for a larger sensitivity of the MOC as compared to the ACC transport, even when approaching eddy saturation. Future process studies designed for disentangling the role of momentum and buoyancy forcing in driving the ACC and MOC are proposed. JF - Ocean Modelling VL - 93 KW - Global ocean?sea ice modeling KW - Model comparisons KW - Southern Ocean meridional overturning circulation KW - Antarctic Circumpolar Current KW - Southern Ocean dynamics SN - 1463-5003 TI - An assessment of Antarctic Circumpolar Current and Southern Ocean Meridional Overturning Circulation during 1958?2007 in a suite of interannual CORE-II simulations SP - 84 AV - none EP - 120 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 - soton413899 UR - https://eprints.soton.ac.uk/413899/ IS - 3 A1 - Feng, Y. A1 - Hare, C.E. A1 - Rose, J.M. A1 - Handy, S.M. A1 - DiTullio, G.R. A1 - Lee, P.A. A1 - Smith, W.O. A1 - Peloquin, J. A1 - Tozzi, S. A1 - Sun, J. A1 - Zhang, Y. A1 - Dunbar, R. B. A1 - Long, M.C. A1 - Sohst, B. A1 - Lohan, M. A1 - Hutchins, D.A. Y1 - 2010/03// N2 -We conducted a factorial shipboard continuous culture experiment to examine the interactive effects of altered iron, irradiance and CO2 on the summer phytoplankton community of the Ross Sea, Antarctica. After 18 days of continuous incubation, iron enrichment increased phytoplankton biomass, nutrient drawdown, diatom and Phaeocystis abundance, and some photosynthetic parameters. High irradiance significantly increased the number of Phaeocystis antarctica colonies, as well as P. antarctica abundance relative to diatoms. Iron and light had significant interactive effects on diatom and P. antarctica pigment concentrations, P. antarctica colony abundance, and Si:N, Si:C, and N:P ratios. The major influence of high CO2 was on diatom community structure, by favoring the large centric diatom Chaetoceros lineola over the small pennate species Cylindrotheca closterium. The ratio of centric to pennate diatoms was significantly responsive to changes in all three variables individually, and to all of their possible two- and three-way combinations. These results suggest that shifts in light, iron, and CO2 and their mutual interactions all play a role in controlling present day Ross Sea plankton community structure, and need to be considered when predicting the possible future responses of biology and biogeochemistry in this region.
JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 57 KW - Co-limitation KW - CO KW - Diatoms KW - Global change KW - Interactive effects KW - Iron limitation KW - Irradiance KW - Phaeocystis KW - Phytoplankton KW - Ross Sea KW - Southern Ocean SN - 0967-0637 TI - Interactive effects of iron, irradiance and CO2 on Ross Sea phytoplankton SP - 368 AV - none EP - 383 ER - TY - JOUR N1 - Funding Information: This research was funded by European Union's Horizon 2,020 research and innovation program under the Marie Sk?odowska?Curie grant agreement No. 834330 (SO?CUP) to BFC. RGW was supported by NERC Grant No. NE/T010657/1. Float data were collected and made freely available by the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Project funded by the National Science Foundation, Division of Polar Programs (NSF PLR?1425989, with extension NSF OPP?1936222), supplemented by NASA, and by the International Argo Program and the NOAA programs that contribute to it. Publisher Copyright: © 2022. The Authors. ID - soton458190 UR - https://eprints.soton.ac.uk/458190/ IS - 11 A1 - Fernández Castro, Bieito A1 - Mazloff, Matthew A1 - Williams, Richard G. A1 - Naveira Garabato, Alberto C. Y1 - 2022/06/16/ N2 - Sub-Antarctic Mode Waters (SAMW) form to the north of the Antarctic Circumpolar Current (ACC) through deep winter mixing. SAMW connect the atmosphere with the oceanic pycnocline, transferring heat and carbon into the ocean interior and supplying nutrients to the northern ocean basins. The processes controlling SAMW ventilation and properties remain poorly understood. Here, we investigate the significance and origin of a ubiquitous feature of SAMW formation regions: The seasonal build-up of a subsurface salinity maximum. With biogeochemical Argo floats, we show that this feature influences SAMW mixed-layer dynamics, and that its formation is associated with a decline in preformed nutrients comparable to biological drawdown in surface waters (?0.15 mol m?2 y?1). Our analysis reveals that these features are driven by advection of warm, salty, nutrient-poor waters of subtropical origin along the ACC. This influx represents a leading-order term in the SAMW physical and biogeochemical budgets, and can impact large-scale nutrient distributions. JF - Geophysical Research Letters VL - 49 KW - Southern Ocean KW - Sub-Antartic Mode Water KW - biogeochemical Argo float KW - mixed layer KW - preformed nutrients KW - subtropical gyre SN - 0094-8276 TI - Subtropical contribution to sub?Antarctic mode waters AV - public EP - 11 ER - TY - JOUR ID - soton49514 UR - https://eprints.soton.ac.uk/49514/ IS - 18-20 A1 - Fielding, Sophie A1 - Ward, Peter A1 - Pollard, Raymond T. A1 - Seeyave, Sophie A1 - Read, Jane F. A1 - Hughes, J. Alan A1 - Smith, Tania A1 - Castellani, Claudia Y1 - 2007/09// N2 - Net sampling within the vicinity of the Crozet archipelago, in the Indian Ocean sector of the Southern Ocean, was conducted during late spring/summer (November 2004?January 2005) to describe the composition, distribution and grazing impact of mesozooplankton, and to investigate their relationships with the prevailing oceanographic regime in the area. The mesozooplankton community was intimately linked with the large-scale physical circulation in the region. To the west and north of the Islands, the sub-Antarctic Front (SAF) presented a strong biogeographic boundary between sub-tropical and sub-Antarctic species. South and east of the SAF, the mesozooplankton community was dominated by Polar Frontal Zone (PFZ) copepod species. Cluster analysis of mesozooplankton abundance data identified two main communities in the PFZ, termed here Island and Oceanic. Island stations, representing the proposed iron-fertilised productive region north of the archipelago, contained an abundance (mean of 2269 ind m?3) of the neritic copepod Drepanopus pectinatus, whose presence indicated that the water had interacted with the Crozet Island shelf at some point. D. pectinatus was present in samples north of Crozet up to the SAF, confirming that water passing the Crozet Islands could be transported throughout the region to the north. The Oceanic stations, south of the Islands and within the SAF, contained similar mesozooplankton abundances and biovolume to the Island stations suggesting little enhanced impact of the iron-fertilised phytoplankton bloom through the mesozooplankton food web.As charismatic and iconic species, penguins can act as ?ambassadors? or flagship species to promote the conservation of marine habitats in the Southern Hemisphere. Unfortunately, there is a lack of reliable, comprehensive, and systematic analysis aimed at compiling spatially explicit assessments of the multiple impacts that the world's 18 species of penguin are facing. We provide such an assessment by combining the available penguin occurrence information from Global Biodiversity Information Facility (>800,000 occurrences) with three main stressors: climate-driven environmental changes at sea, industrial fisheries, and human disturbances on land. Our analyses provide a quantitative assessment of how these impacts are unevenly distributed spatially within species' distribution ranges. Consequently, contrasting pressures are expected among species, and populations within species. The areas coinciding with the greatest impacts for penguins are the coast of Perú, the Patagonian Shelf, the Benguela upwelling region, and the Australian and New Zealand coasts. When weighting these potential stressors with species-specific vulnerabilities, Humboldt (Spheniscus humboldti), African (Spheniscus demersus), and Chinstrap penguin (Pygoscelis antarcticus) emerge as the species under the most pressure. Our approach explicitly differentiates between climate and human stressors, since the more achievable management of local anthropogenic stressors (e.g., fisheries and land-based threats) may provide a suitable means for facilitating cumulative impacts on penguins, especially where they may remain resilient to global processes such as climate change. Moreover, our study highlights some poorly represented species such as the Northern Rockhopper (Eudyptes moseleyi), Snares (Eudyptes robustus), and Erect-crested penguin (Eudyptes sclateri) that need internationally coordinated efforts for data acquisition and data sharing to understand their spatial distribution properly.
JF - Global Change Biology VL - 30 KW - environmental trends KW - fisheries KW - global change KW - human pressures KW - marine systems KW - sentinels KW - Southern Hemisphere KW - threats SN - 1354-1013 TI - Climate and human stressors on global penguin hotspots: current assessments for future conservation AV - public EP - 18 ER - TY - JOUR ID - soton11043 UR - https://eprints.soton.ac.uk/11043/ IS - 8 A1 - Gomez, Basil A1 - Carter, Lionel A1 - Trustrum, Noel A. A1 - Palmer, Alan S. A1 - Roberts, Andrew P. Y1 - 2004/// N2 - A synchronous textural variation in intercorrelated, high-resolution sediment records from floodplain, continental-shelf, and continental-slope settings of the eastern North Island, New Zealand, provides evidence of increased storminess after ca. 4 ka. An upcore change in sediment texture reflects the transition to landsliding, which supplanted fluvial incision as the dominant mode of sediment production in the middle Holocene. This signal, which appears in all three records, indicates a regional response to external forcing and records the impact of an intensified atmospheric circulation marking the establishment of the contemporary climate that is strongly influenced by the El Niño?Southern Oscillation. The change in climate was a hemispheric event, and in the Southern Hemisphere its timing is confirmed by independent proxy records from elsewhere in New Zealand and the circum?South Pacific region. JF - Geology VL - 32 KW - climate change KW - El Niño?Southern Oscillation KW - landsliding KW - New Zealand SN - 0091-7613 TI - El Nino-Southern Oscillation signal associated with middle Holocene climate change in intercorrelated terrestrial and marine sediment cores, North Island, New Zealand SP - 653 AV - none EP - 656 ER - TY - JOUR ID - soton355813 UR - https://eprints.soton.ac.uk/355813/ IS - 6 A1 - Groves, Jon A. A1 - Waller, Martyn P. A1 - Grant, Michael J. A1 - Schofield, J. Edward Y1 - 2012/// N2 - The lowland heathlands of southern England comprise ca. 14% of the total area of this habitat in Europe yet their history is poorly understood. This paper presents the first detailed palaeoecological evidence (combining palynological, microscopic charcoal and radiocarbon data) relating to the origin and long-term dynamics of heathland vegetation in southern England. Valley peat sites, situated on the Lower Greensand Group (coarse-grained sandstones) at Conford (Hampshire) and Hurston Warren (West Sussex) have been investigated. The sequence from Conford indicates the unusually late survival of Pinus sylvestris (to as late as ca. 6050 cal. B.P.) in southern England. This is attributed to edaphic factors and, after ca. 7050 cal. B.P., to frequent fires. After intervening phases of dominance by deciduous woodland, heathland vegetation became established in the proximity of both sites in the Late Bronze Age (ca. 3000 cal. B.P.) with increases in indicators of grazing and burning demonstrating an association between the development of heathland and human activity. Thereafter, the pollen and charcoal records show that the vegetation remained in a dynamic state as the scale and nature of human activity varied through time. Major expansions in the extent of heathland occurred relatively recently; after ca. 1450 cal. B.P. at Hurston Warren and after ca. 850 cal. B.P. at Conford. A review of the palaeoecological evidence suggests that the most intense use and greatest coverage of heathland in southern England probably occurred during the medieval to post-medieval periods. JF - Vegetation History and Archaeobotany VL - 21 KW - Pollen analysis KW - Lowland heath KW - Human impact KW - Pinus KW - Southern England KW - Microscopic charcoal SN - 0939-6314 TI - Long-term development of a cultural landscape: the origins and dynamics of lowland heathland in southern England SP - 453 AV - none EP - 470 ER - TY - JOUR ID - soton65638 UR - http://www.iwaponline.com/jwh/007/0259/0070259.pdf IS - 2 A1 - Gundry, Stephen W. A1 - Wright, James A. A1 - Conroy, Ronán M. A1 - du Preez, Martella A1 - Genthe, Bettina A1 - Moyo, Sibonginkosi A1 - Mutisi, Charles A1 - Potgieter, Natasha Y1 - 2009/// N2 - The objective of this cohort study was to assess risk factors for child dysentery and watery diarrhoea. The study participants consisted of 254 children aged 12?24 months in rural SouthThe Antarctic Peninsula (AP) shelf is an important source of dissolved iron (Fe) to the upper ocean in the southern Scotia Sea, one of the most productive regions of the Southern Ocean. Here we present results from a four-year (2003-2006) numerical simulation using a regional coupled physical-biogeochemical model to assess the Fe sources and transport on the AP shelf and toward the southern Scotia Sea. The model was validated with a suite of data derived from in situ surveys and remote sensing. Model results indicate that sediments in the AP shelf and the South Orkney Plateau (SOP) provide the dominant source of Fe to the upper 500 m in the southern Scotia Sea. Additional Fe inputs to the region are associated with the Antarctic Circumpolar Current (ACC) and the northern limb of the Weddell Gyre, deep-ocean sediment sources, dust deposition, and icebergs. Fe on the AP shelf originates primarily from sediments on the relatively shallow inner shelf and is directly injected into the water column and subsequently transported toward Elephant Island by the confluent shelf currents. Off-shelf Fe export is primarily through entrainment of shelf waters by the ACC's Southern Boundary frontal jet along the northern edge of the AP shelf, the Hesperides Trough, and the SOP shelf. About 70% of the off-shelf export takes place below the surface mixed layer, and is subsequently re-supplied to the euphotic zone through vertical mixing, mainly during austral fall and winter. The exported shelf-derived Fe is then advected downstream by the ACC and Weddell Gyre and spread over the southern and eastern Scotia Seas. Taken together, shelf Fe export witin top 500 m meets nearly all of the Fe demand of phytoplankton photosynthesis in the southern Scotia Sea. Waters with elevated Fe concentrations in the Scotia Sea are largely restricted to south of the Southern ACC Front.
JF - Deep-Sea Research Part I: Oceanographic Research Papers KW - Antarctic Peninsula KW - Coupled physical-biogeochemical model KW - Iron (Fe) KW - Off-shelf transport KW - Shelf sediment KW - Southern Scotia Sea SN - 0967-0637 TI - Fe sources and transport from the Antarctic Peninsula shelf to the southern Scotia Sea AV - public ER - TY - JOUR ID - soton364845 UR - https://eprints.soton.ac.uk/364845/ IS - 6 A1 - Jullion, Loïc A1 - Naveira Garabato, Alberto C. A1 - Bacon, Sheldon A1 - Meredith, Michael P. A1 - Brown, Pete J. A1 - Torres-Valdés, Sinhué A1 - Speer, Kevin G. A1 - Holland, Paul R. A1 - Dong, Jun A1 - Bakker, Dorothée A1 - Hoppema, Mario A1 - Loose, Brice A1 - Venables, Hugh J. A1 - Jenkins, William J. A1 - Messias, Marie-José A1 - Fahrbach, Eberhard Y1 - 2014/06// N2 - The horizontal and vertical circulation of the Weddell Gyre is diagnosed using a box inverse model constructed with recent hydrographic sections and including mobile sea ice and eddy transports. The gyre is found to convey 42 ± 8 Sv (1 Sv = 106 m3 s-1) across the central Weddell Sea and to intensify to 54±15 Sv further offshore. This circulation injects 36±13 TW of heat from the Antarctic Circumpolar Current to the gyre, and exports 51 ± 23 mSv of freshwater, including 13 ± 1 mSv as sea ice to the mid-latitude Southern Ocean. The gyre's overturning circulation has an asymmetric double-cell structure, in which 13 ± 4 Sv of Circumpolar Deep Water (CDW) and relatively light Antarctic Bottom Water (AABW) are transformed into upper-ocean water masses by mid-gyre upwelling (at a rate of 2 ± 2 Sv) and into denser AABW by downwelling focussed at the western boundary (8 ± 2 Sv). The gyre circulation exhibits a substantial throughflow component, by which CDW and AABW enter the gyre from the Indian sector, undergo ventilation and densification within the gyre, and are exported to the South Atlantic across the gyre's northern rim. The relatively modest net production of AABW in the Weddell Gyre (6±2 Sv) suggests that the gyre's prominence in the closure of the lower limb of global oceanic overturning stems largely from the recycling and equatorward export of Indian-sourced AABW. JF - Journal of Geophysical Research: Oceans VL - 119 KW - Weddell Sea KW - Southern Ocean KW - meridional overturning circulation KW - oceanography KW - sea ice KW - climate SN - 2169-9275 TI - The contribution of the Weddell Gyre to the lower limb of the global overturning circulation SP - 3357 AV - public EP - 3377 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 - soton59901 UR - https://eprints.soton.ac.uk/59901/ IS - 2 A1 - Kaeda, J. A1 - Chase, A. A1 - Goldman, J.M. Y1 - 2002/// N2 - For patients with chronic myeloid leukaemia, methods for monitoring response to treatment have changed considerably in recent years. In the 1980s, the principal approach was repeated examination of bone marrow metaphases for the presence of the Ph chromosome in patients treated by interferon-alpha (IFN-alpha) or allogeneic stem cell transplantation. The use of fluorescence in situ hybridisation (FISH) techniques to detect the BCR-ABL fusion gene in Ph-positive leukaemia cells increased the sensitivity of cytogenetic studies to some degree. In the last 10 years, the reverse-transcriptase polymerase chain reaction (RT-PCR) has proved extremely valuable for assessing and monitoring minimal residual disease in patients who achieve Ph negativity after treatment with IFN-alpha or with the new Abl tyrosine kinase inhibitor imatinib mesylate or after allogeneic stem cell transplantation (SCT). Results are consistent with the notion that the majority of long-term survivors after allogeneic SCT are probably 'cured'; for other patients monitored serially in complete cytogenetic remission, rising numbers of BCR-ABL transcripts detected by RT-PCR can indicate the need for further therapy JF - Acta Haematologica VL - 107 KW - neoplasm proteins KW - stem cell transplantation KW - interferon-alpha KW - methods KW - review KW - rna KW - standards KW - therapy KW - bone KW - proteins KW - southern KW - london KW - western KW - neoplasm KW - bone marrow KW - residual KW - pathology KW - humans KW - cytogenetic analysis KW - polymerase chain reaction KW - protein KW - myeloid KW - analysis KW - cell transplantation KW - leukemia KW - fluorescence KW - transplantation KW - blotting KW - metaphase KW - diagnosis KW - tyrosine KW - chronic KW - patients KW - disease KW - reverse transcriptase polymerase chain reaction KW - genetics SN - 0001-5792 TI - Cytogenetic and molecular monitoring of residual disease in chronic myeloid leukaemia SP - 64 AV - none EP - 75 ER - TY - JOUR ID - soton468931 UR - https://eprints.soton.ac.uk/468931/ IS - 3 A1 - Kampkötter, A A1 - Ridgers, I A1 - Johnston, D A A1 - Rollinson, D A1 - Kunz, W A1 - Grevelding, C G Y1 - 1999/03// N2 - In an attempt to identify and characterize molecules throught likely to play important roles during the development of schistosomes, we started to search for signal transductionmolecules in Schistosoma mansoniRecently, we reported the localization of a gene for transient neonatal diabetes mellitus (TNDM), a rare form of childhood diabetes, to an approximately 5.4 Mb region of chromosome 6q24. We have also shown that TNDM is associated with both paternal uniparental disomy (UPD) of chromosome 6 and paternal duplications of the critical region. The sequencing of P1-derived artificial chromosome clones from within the region of interest has allowed us to further localize the gene and to investigate the methylation status of the region. The gene is now known to reside in a 300-400 kb region of 6q24 which contains several CpG islands. At one island we have demonstrated differential DNA methylation between patients with paternal UPD of chromosome 6 and normal controls. In addition, two patients with TNDM, in whom neither paternal UPD of chromosome 6 nor duplication of 6q24 have been found, show a DNA methylation pattern identical to that of patients with paternal UPD of chromosome 6. Control individuals show a hemizygous methylation pattern. These results show that TNDM can be associated with a methylation change and identify a novel methylation imprint on chromosome 6 associated with TNDM.
JF - Human Molecular Genetics VL - 9 KW - Blotting KW - Southern KW - Chromosomes KW - Human KW - Pair 6 KW - CpG Islands KW - DNA Methylation KW - Diabetes Mellitus KW - Expressed Sequence Tags KW - Fathers KW - Female KW - Gene Dosage KW - Gene Duplication KW - Genomic Imprinting KW - Humans KW - Infant KW - Newborn KW - Male KW - Mothers KW - Polymerase Chain Reaction KW - Restriction Mapping KW - Sequence Tagged Sites KW - Journal Article KW - Research Support KW - Non-U.S. Gov't SN - 0964-6906 TI - An imprinted locus associated with transient neonatal diabetes mellitus SP - 589 AV - none EP - 96 ER - TY - JOUR ID - soton339896 UR - https://eprints.soton.ac.uk/339896/ IS - 4 A1 - Marks, Monique A1 - Fleming, Jenny Y1 - 2006/// N2 - This paper explores the struggles for labour and social rights on the part of police officers in democratising countries. The paper suggests that the rights of police officers and labour?management relations are important issues to be acknowledged if we are serious about deepening the democratic practices of police, particularly in democratising countries. These issues should be deliberated among policing scholars and police managers as well as important international regulatory organisations such as the ILO whose current regulatory frameworks inadvertently restrict police worker rights.The ocean is affected by multiple anthropogenic stressors including climate change, the effects of which are already evident in many ocean ecosystems. The ABACuS v2 end-to-end model together with climate projections from the NEMO-MEDUSA 2.0 model were used to evaluate the effects of fishing, warming and horizontal and vertical mixing on the southern Benguela upwelling system. Of the drivers examined in this study, warming had the greatest effect on species biomass, with mainly negative effects. The magnitude of the impacts of warming intensified from the RCP 2.6 to the 8.5 emission scenario. Fishing negatively affected demersal and large pelagic fish, which in turn resulted in a biomass increase of forage fish due to a decrease in predation pressure. Water mixing was found to have minor indirect effects on zooplankton biomass and fish. The responses of species and species groups to the combined effects of fishing and warming were approximately equally divided between additive, synergistic and antagonistic. Interpretation of our model results suggests that the southern Benguela system is likely to be affected by climate change, including substantial changes in the abundance of some species important to the region's fisheries. Future planning for fisheries needs to take this into account, including through management that strives to maintain the resilience of key species and the system as a whole. In line with previous studies on the southern Benguela, the results reinforce the importance of including consideration of the indirect and combined impacts of climate change and fishing in management and planning.
JF - Fisheries Oceanography KW - Climate change KW - Ecosystem impacts KW - Fishing KW - Southern Benguela SN - 1054-6006 TI - Evaluating the effects of climate change in the southern Benguela upwelling system using the Atlantis modelling framework SP - 1 AV - none EP - 15 ER - TY - JOUR N1 - Funding Information: We wish to express our thanks to the captain and crew of the MV Akademik Shokalskiy and Henk Haazen and Kali Kahn on the Tiama for help in the field. This work was supported by the Australasian Antarctic Expedition 2013?2014, the Australian Research Council (CE170100015; FL100100195, Funding Information: FT120100004, and DP130104156) and the University of New South Wales. SJR, JMW and MSM were supported by SSIF funding for Crown Research Institutes from the New Zealand Ministry of Business, Innovation and Employment?s Science and Innovation Group. Research on the New Zealand subantarctic Auckland and Campbell Islands was undertaken under Department of Conservation National Authorisation Numbers 37687-FAU and 39761-RES. Funding Information: We wish to express our thanks to the captain and crew of the MV Akademik Shokalskiy and Henk Haazen and Kali Kahn on the Tiama for help in the field. This work was supported by the Australasian Antarctic Expedition 2013?2014, the Australian Research Council (CE170100015; FL100100195, FT120100004, and DP130104156) and the University of New South Wales. SJR, JMW and MSM were supported by SSIF funding for Crown Research Institutes from the New Zealand Ministry of Business, Innovation and Employment?s Science and Innovation Group. Research on the New Zealand subantarctic Auckland and Campbell Islands was undertaken under Department of Conservation National Authorisation Numbers 37687-FAU and 39761-RES. ID - soton475018 UR - https://eprints.soton.ac.uk/475018/ IS - 1 A1 - Palmer, Jonathan G. A1 - Turney, Chris S.M. A1 - Thomas, Zoë A. A1 - Fenwick, Pavla A1 - Richardson, Sarah J. A1 - Wilmshurst, Janet M. A1 - McGlone, Matt S. Y1 - 2023/// N2 -Interspecific variation in tree growth rate and maximum age is central to understanding and predicting the dynamics of forest ecosystems. While there are abundant sources of this information for economically important New Zealand timber species and other common tree species, data for trees from subantarctic environments are almost entirely lacking. Here we present measurements of growth from Auckland and Campbell Islands for three species: Metrosideros umbellata (southern r?t?; Myrtaceae, n = 1 site), a canopy dominant; Dracophyllum sp. (inaka; Ericaceae, n = 5 sites), a widespread small tree; and Olearia lyallii (t?pare, subantarctic tree daisy; Asteraceae, n = 2 sites), a species native to Snares Island that has naturalised on the Auckland Islands. Our data showed large differences in tree growth rates among and within species across islands. Growth rates varied eight-fold (i.e. from 0.34 mm yr?1 to 2.78 mm yr?1), being greatest in Olearia lyallii, least in Dracophyllum sp. and intermediate in Metrosideros umbellata. Comparisons of the five Dracophyllum sites suggest that these trees experience reduced growth rates and reach older ages when in competition with the bigger southern r?t? (M. umbellata) trees, possibly due to the larger southern r?t? providing protection from wind-throw. Measurements of resprouted southern r?t? trees showed a variable juvenile-phase radial growth rate, highlighting the need for caution in extrapolating the likely ages of bigger trees. Remeasured individuals of Olearia lyallii growing among taller southern r?t? trees showed slow growth rates compared to much faster rates seen in a nearby monospecific stand. Overall, the variability in growth seen by all three species illustrates that tree size cannot be used to indicate age in these subantarctic islands.
JF - New Zealand Journal of Ecology VL - 47 KW - forest conservation KW - radiocarbon dating KW - remote islands KW - Southern Ocean KW - southern tree limit KW - World Heritage Area SN - 0110-6465 TI - Growth rates and ages of some key tree species from subantarctic Auckland and Campbell Islands AV - public EP - 8 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.Killer whales at subantarctic Marion Island have been subjected to several scientific studies. In contrast, up until recently, there has been only one record of these animals documented for neighbouring Prince Edward Island. We here report on killer whale observations at Prince Edward Island during March 2012. During 3 days of opportunistic observations at a fur seal colony on the island, killer whales were sighted on six occasions. These probably represented three different pods numbering 11 individuals in total. During all sightings, individuals were seen hunting subantarctic fur seal pups, with four successful predatory events observed.
VL - 35 TI - Killer whale predation on subantarctic fur seals at Prince Edward Island, Southern Indian Ocean AV - none EP - 1772 N1 - Funding Information: Acknowledgments We would like to thank the Department of Environmental Affairs who provided logistic and financial support for the Prince Edward Island autumn survey. We are grateful for the insightful comments received from two anonymous reviewers. Copyright: Copyright 2012 Elsevier B.V., All rights reserved. Y1 - 2012/11// JF - Polar Biology KW - Apex predators KW - Feeding ecology KW - Population regulation KW - Southern Ocean SN - 0722-4060 SP - 1767 ER - TY - JOUR ID - soton455663 UR - https://eprints.soton.ac.uk/455663/ IS - 11 A1 - Pistorius, Pierre A1 - Hindell, Mark A1 - Crawford, Robert A1 - Makhado, Azwianewi A1 - Dyer, Bruce A1 - Reisinger, Ryan Y1 - 2017/06// N2 -King penguins make up the bulk of avian biomass on a number of sub-Antarctic islands where they have a large functional effect on terrestrial and marine ecosystems. The same applies at Marion Island where a substantial proportion of the world population breeds. In spite of their obvious ecological importance, the at-sea distribution and behavior of this population has until recently remained entirely unknown. In addressing this information deficiency, we deployed satellite-linked tracking instruments on 15 adult king penguins over 2 years, April 2008 and 2013, to study their post-guard foraging distribution and habitat preferences. Uniquely among adult king penguins, individuals by and large headed out against the prevailing Antarctic Circumpolar Current, foraging to the west and southwest of the island. On average, individuals ventured a maximum distance of 1,600 km from the colony, with three individuals foraging close to, or beyond, 3,500 km west of the colony. Birds were mostly foraging south of the Antarctic Polar Front and north of the southern boundary of the Antarctic Circumpolar Current. Habitat preferences were assessed using boosted regression tree models which indicated sea surface temperate, depth, and chorophyll a concentration to be the most important predictors of habitat selection. Interestingly, king penguins rapidly transited the eddy-rich area to the west of Marion Island, associated with the Southwest Indian Ocean Ridge, which has been shown to be important for foraging in other marine top predators. In accordance with this, the king penguins generally avoided areas with high eddy kinetic energy. The results from this first study into the behavioral ecology and at-sea distribution of king penguins at Marion Island contribute to our broader understanding of this species.
JF - Ecology and Evolution VL - 7 KW - foraging KW - habitat selection KW - movement KW - seabirds KW - Southern Ocean SN - 2045-7758 TI - At-sea distribution and habitat use in king penguins at sub-Antarctic Marion Island SP - 3894 AV - public EP - 3903 ER - TY - JOUR ID - soton49509 UR - https://eprints.soton.ac.uk/49509/ IS - 18-20 A1 - Planquette, H. A1 - Statham, P.J. A1 - Fones, G.R. A1 - Charette, M.A. A1 - Moore, C.M. A1 - Salter, I. A1 - Nedelec, F.H. A1 - Taylor, S.L. A1 - French, M. A1 - Baker, A.R. A1 - Mahowald, N. A1 - Jickells, T.D. Y1 - 2007/// N2 - The annual phytoplankton bloom occurring north of the Crozet Plateau provides a rare opportunity to examine the hypothesis that natural iron fertilization can alleviate high-nutrient low-chlorophyll (HNLC) conditions normally associated with the Southern Ocean. Therefore, during CROZet natural iron bloom and EXport experiment (CROZEX), a large multidisciplinary study performed between November 2004 and January 2005, measurements of total dissolved iron (DFe0.2 ?m) were made on seawater from around the islands and atmospheric iron deposition estimated from rain and aerosol samples.Mangrove distribution patterns at regional scales are influenced by additional factors besides temperature and rainfall regimes. This study identified abiotic drivers of mangrove area cover along the high-energy, wave-dominated coastline of South Africa. This is one of the southernmost locations globally for mangroves. A structural equation model (SEM) was used to delineate relationships between multiple variables that represented climatic and geomorphological drivers of current mangrove distribution patterns. Floodplain area, inlet stability, and the flow regime of the estuary were identified as significant predictors of mangrove area. The results of this study confirm that for this region mangrove distribution is controlled by coastal topographical features and estuarine dynamics rather than temperature minima. This is similar to other high-energy, wave-dominated coasts of Australia, Brazil, and New Zealand. Future research should, therefore, incorporate regional-scale factors that restrict current distributions as they could inform on potential limitations to expansion, particularly for southern hemisphere range limits.
JF - Estuarine, Coastal and Shelf Science VL - 226 KW - Biogeographic patterns KW - Climatic drivers KW - Estuaries KW - Geomorphological drivers KW - Southern Africa KW - Structural equation modelling SN - 0272-7714 TI - Drivers of mangrove distribution at the high-energy, wave-dominated, southern African range limit AV - public EP - 24 ER - TY - JOUR ID - soton49506 UR - https://eprints.soton.ac.uk/49506/ IS - 18-20 A1 - Read, J.F. A1 - Pollard, R.T. A1 - Allen, J.T. Y1 - 2007/// N2 - Two stations only 20 km apart were observed to have quite different biological and biogeochemical characteristics. The first site had low concentrations of chlorophyll and sufficient nutrients to support phytoplankton growth. The second site had high concentrations of chlorophyll, depleted nutrient concentrations and significant export of phytodetrital material had taken place. The two sites were located in the Polar Frontal Zone of the Southern Ocean to the northwest of the Crozet Islands. The main physical difference between the two sites was in the depth of the mixed layer. At the first site, the mixed layer was deep and well mixed, whereas the second site had a shallow, stratified layer; otherwise the horizontal gradients of physical properties were weak. Survey data from the surrounding area showed that the productive site was located on the edge of a filament of water drawn into a developing meander of the Subantarctic Front. Remotely sensed data provided a history of the growth of the meander in the Subantarctic Front and its development into an eddy in the Polar Frontal Zone. The dynamics associated with the filament in the meander were clearly important in driving the primary productivity, as an intrusion of saline water into adjacent fresher water generated a shallow mixed layer and conditions suitable for phytoplankton growth. The dynamics promoting conditions favourable to phytoplankton growth continued to operate as chlorophyll was enhanced in the eddy after the main bloom had died away. Later measurements suggested that the surface layer had changed from diatom dominated to a coccolithophore or calcite-rich community. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 54 KW - Mesoscale features KW - Oceanic eddies KW - Ocean circulation KW - Algal bloom KW - Subantarctic Front KW - Southern Ocean KW - Indian Ocean KW - Polar Frontal Zone KW - 45°S KW - 50°E SN - 0967-0645 TI - Sub-mesoscale structure and the development of an eddy in the Subantarctic Front north of the Crozet Islands SP - 1930 AV - none EP - 1948 ER - TY - JOUR ID - soton354007 UR - https://eprints.soton.ac.uk/354007/ A1 - Reed, Adam A1 - Morris, J.P. A1 - Linse, K. A1 - Thatje, S. Y1 - 2013/11// N2 - The ecology of Antarctic deep-sea fauna is poorly understood and few studies have gone beyond assessing biodiversity when comparing deep regions of the Southern Ocean. Protobranch bivalves are ubiquitous in the deep ocean and are widely distributed in the Southern Ocean. This paper examines the potential responses to environmental differences in the common protobranchs Yoldiella valettei, Yoldiella ecaudata, and Yoldiella sabrina from contrasting deep-sea environments of the Weddell Sea, Scotia Sea, Amundsen Sea, and South Atlantic. There are significant differences in morphology between deep-sea regions in all species and a significant difference in shell weight in Y. valettei between the Amundsen Sea and Weddell Seas. Growth rates of Y. valettei and Y. ecaudata in the Amundsen Sea are also higher than elsewhere and Y. valettei have heaviest shells in the Amundsen Sea, suggesting more favourable conditions for calcification and growth. The plasticity observed among deep-sea regions in the Southern Ocean is likely to be driven by different oceanographic influences affecting temperature and food fluxes to the benthos, and demonstrate the species? ability to differentially adapt between cold-stenothermal environments. This study suggests that subtle changes in the environment may lead to a divergence in the ecology of invertebrate populations and showcases the protobranch bivalves as a future model group for the study of speciation and radiation processes through cold-stenothermal environments. JF - Deep Sea Research Part I: Oceanographic Research Papers VL - 81 KW - antarctic KW - bivalve KW - plasticity KW - growth KW - morphology KW - southern ocean SN - 0967-0637 TI - Plasticity in shell morphology and growth among deep-sea protobranch bivalves of the genus Yoldiella (Yoldiidae) from contrasting Southern Ocean regions SP - 14 AV - restricted EP - 24 ER - TY - JOUR ID - soton469008 UR - https://eprints.soton.ac.uk/469008/ IS - 1 A1 - Reisinger, R. R. A1 - de Bruyn, P. J.N. A1 - Tosh, C. A. A1 - Oosthuizen, W. C. A1 - Mufanadzo, N. T. A1 - Bester, M. N. Y1 - 2011/04// N2 -The diet of killer whales Orcinus orca was investigated from 48 predation events observed during 823 sightings at sub-Antarctic Marion Island between 2006 and 2009. From these events, there were 10 cases where prey could be identified. Killer whales fed on fur seals Arctocephalus tropicalis, elephant seals Mirounga leonina and penguins. Constant effort (dedicated) observations (259 hours, 2008-2009) showed that the peak in killer whale abundance was between September and December with a secondary peak between April and May, which coincided with peaks in the abundance of seals and penguins.
JF - African Journal of Marine Science VL - 33 KW - Diet KW - Foraging KW - Orcinus orca KW - Seals KW - Seasonal occurrence KW - Southern ocean SN - 1814-232X TI - Prey and seasonal abundance of killer whales at sub-Antarctic Marion Island SP - 99 AV - none EP - 105 ER - TY - JOUR ID - soton469010 UR - https://eprints.soton.ac.uk/469010/ IS - 9 A1 - Reisinger, Ryan R. A1 - Bester, Marthán N. Y1 - 2010/// N2 -Southern elephant seals range extensively during regular foraging excursions. Despite this they are highly philopatric and long range dispersal is rare. At Gough Island, southern Atlantic Ocean, we observed a breeding adult male elephant seal during September 2009, which had been tagged on its natal beach at Marion Island, southern Indian Ocean, in November 1998. The individual was resighted only once on Marion Island, 6 months after tagging. This 3,860 km movement represents dispersal (and likely gene flow) between distinct populations from different elephant seal geographical provinces. Given the polygynous breeding system of this species, the presence of this single male may have a disproportionate genetic effect on the small number of southern elephant seals breeding at Gough Island.
JF - Polar Biology VL - 33 KW - Emigration KW - Gene flow KW - Gough Island KW - Marion Island KW - Mirounga leonina KW - Movement KW - Natal dispersal KW - Southern Ocean SN - 0722-4060 TI - Long distance breeding dispersal of a southern elephant seal SP - 1289 AV - none EP - 1291 ER - TY - JOUR ID - soton455442 UR - https://eprints.soton.ac.uk/455442/ IS - 1 A1 - Reisinger, Ryan R. A1 - Landman, Marietjie A1 - Mgibantaka, Nonkoliso A1 - Smale, Malcolm J. A1 - Bester, Marthán N. A1 - De Bruyn, P. J.Nico A1 - Pistorius, Pierre A. Y1 - 2018/04/20/ N2 - Antarctic (Arctocephalus gazella) and Subantarctic (A. tropicalis) fur seals are important predators in the Southern Ocean. Marion Island (southern Indian Ocean) hosts the largest sympatric breeding populations of these two species. Environmental and population changes here over two decades may have influenced their diet and trophic interactions. To quantify diet, we analysed prey remains in scat samples from Antarctic (661 scats) and Subantarctic (750 scats) fur seals collected at Marion Island (2006?2010). We assessed diet composition over time and calculated dietary overlap. The diet of both species was dominated by fish prey (98.2% and 99.4% of prey items), mainly myctophids. Antarctic fur seals consumed small numbers of penguins, cephalopods and crustaceans. In Subantarctic fur seal scats, crustaceans and cephalopods were rare and penguin remains were absent. The diets of the two species overlapped substantially (Pianka?s index = 0.98), however, small but significant differences in the relative proportions of prey were evident. Seasonal and annual diet changes suggest that their diet is similarly influenced by patterns of local prey availability and abundance. Despite substantial changes in the population size and trajectory of Antarctic and Subantarctic fur seals ? which would be expected to influence trophic interactions between them ? comparing our data to those from earlier studies (1989?2000) did not reveal significant long-term dietary changes in either species. JF - Polar Research VL - 37 KW - foraging KW - marine mammal KW - pinniped KW - Prey KW - scats KW - Southern Ocean SN - 0800-0395 TI - Overlap and temporal variation in the diets of sympatric Antarctic and Subantarctic fur seals (Arctocephalus spp.) at Marion Island, Prince Edward Islands AV - public ER - TY - JOUR ID - soton469013 UR - https://eprints.soton.ac.uk/469013/ IS - 4 A1 - Reisinger, Ryan R. A1 - McIntyre, Trevor A1 - Bester, Marthán N. Y1 - 2010/04// N2 -Goose barnacles (Lepas australis) attached to satellite-relay data loggers were carried by three southern elephant seals (Mirounga leonina) from Marion Island. Their movements across the Polar Frontal Zone are presented, providing further evidence that megafauna are potential vectors for the transport of species into the Southern Ocean.
JF - Polar Biology VL - 33 KW - Lepas australis KW - Southern elephant seal KW - Southern Ocean KW - Species transport SN - 0722-4060 TI - Goose barnacles hitchhike on satellite-tracked southern elephant seals SP - 561 AV - none EP - 564 ER - TY - JOUR ID - soton469006 UR - https://eprints.soton.ac.uk/469006/ IS - 2 A1 - Reisinger, Ryan R. A1 - de Bruyn, P. J.N. A1 - Bester, Marthán N. N2 -Killer whales Orcinus orca are apex predators known to have important effects on marine ecosystems. A fundamental step towards understanding their role in ecosystems, and vital for their informed management and conservation, is the rigorous estimation of their abundance. Studies concerning this species have used mark-recapture analytical techniques to estimate abundance, but enumeration of identifiable individuals is more common. This study estimated the abundance of killer whales occurring inshore at subantarctic Marion Island. Mark-recapture analyses were performed using nearly 10 000 photographs taken from 2006 to 2009. Using careful quality control criteria, we identified 37 ind. The evident capture heterogeneity violates the underlying assumptions of the open population POPAN parameterization in the software program MARK we initially used. We thus used the simpler Chapman modified Lincoln-Petersen estimator, calculating a population size of 37 ind. (95% CI = 29 to 44) for the period 2006 to 2007 and 32 ind. (95% CI = 30 to 33) for 2007 to 2008. Both estimates are close to the catalogue size, suggesting that enumeration is an accurate measure of abundance in this study. Our results are comparable to recent abundance estimates for the neighbouring Crozet Archipelago (~1000 km due east). No rigorous approach has been used previously to estimate the abundance of killer whales at Marion Island. This estimate provides a foundation for further research related to the sociality and potential ecological impact of this population of killer whales in the Southern Ocean.
VL - 12 TI - Abundance estimates of killer whales at subantarctic Marion Island AV - none EP - 185 N1 - Copyright: Copyright 2012 Elsevier B.V., All rights reserved. Y1 - 2011/// JF - Aquatic Biology KW - Count KW - Mark-recapture KW - Orcinus orca KW - Photo-identification KW - Population size KW - Southern ocean SN - 1864-7782 SP - 177 ER - TY - JOUR ID - soton41430 UR - https://eprints.soton.ac.uk/41430/ IS - 2-4 A1 - Rijkenberg, M.J.A. A1 - Fischer, A.C. A1 - Kroon, J.J. A1 - Gerringa, L.J.A. A1 - Timmermans, K.R. A1 - Wolterbeek, H.Th. A1 - de Baar, H.J.W. Y1 - 2005/// N2 - An iron enrichment experiment, EisenEx, was performed in the Atlantic sector of the Southern Ocean during the Antarctic spring of 2000. Deck incubations of open ocean water were performed to investigate the influence of ultraviolet B (UVB: 280-315 nm) and ultraviolet A (UVA: 315-400 nm) on the speciation of iron in seawater, using an addition of the radioisotopes Fe-59(III) (1.25 nM) or Fe-55(III) (0.5 nM). Seawater was sampled inside and outside the iron-enriched region. The radioisotopic Fe(II) concentration was monitored during daylight under three different light conditions: the full solar spectrum (total), total minus UVB, and total minus UVB+UVA. A distinct diel cycle was observed with a clear distinction between the three different light regimes. A clear linear relationship was found for the concentration of radioisotopic Fe(II) versus irradiance. UVB produced most of the Fe(II) followed by UVA and visible light (VIS: 400-700 nm), respectively. UVB produced 4.89 and 0.69 pM m(2) W-1 radioisotopic Fe(II) followed by UVA with 0.33 and 0.10 pM M-2 W-1 radioisotopic Fe(II) and VIS with 0.04 and 0.03 pM m(2) W-1 radioisotopic Fe(II). JF - Marine Chemistry VL - 93 KW - iron KW - photoreduction KW - UV KW - Southern Ocean KW - EisenEx SN - 0304-4203 TI - The influence of UV irradiation on the photoreduction of iron in the Southern Ocean SP - 119 AV - none EP - 129 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 - soton50855 UR - https://eprints.soton.ac.uk/50855/ IS - 1-2 A1 - Rijkenberg, Micha J.A. A1 - Gerringa, Loes J.A. A1 - Timmermans, Klaas R. A1 - Fischer, Astrid C. A1 - Kroon, Koos J. A1 - Buma, Anita G.J. A1 - Wolterbeek, Bert Th. A1 - de Baar, Hein J.W. Y1 - 2008/02/16/ N2 - Short term (2 days) laboratory experiments were performed to study the change in irradiance induced production of Fe(II) inOceanic island flora is vulnerable to future climate warming, which is likely to promote changes in vegetation composition, and invasion of non-native species. Sub-Antarctic islands are predicted to experience rapid warming during the next century; therefore, establishing trajectories of change in vegetation communities is essential for developing conservation strategies to preserve biological diversity. We present a Late-glacial-early Holocene (16 500?6450 cal a bp) palaeoecological record from Hooker's Point, Falkland Islands (Islas Malvinas), South Atlantic. This period spans the Pleistocene-Holocene transition, providing insight into biological responses to abrupt climate change. Pollen and plant macrofossil records appear insensitive to climatic cooling during the Late-glacial, but undergo rapid turnover in response to regional warming. The absence of trees throughout the Late-glacial-early Holocene enables the recognition of far-travelled pollen from southern South America. The first occurrence of Nothofagus (southern beech) may reflect changes in the strength and/or position of the Southern Westerly Wind Belt during the Late-glacial period. Peat inception and accumulation at Hooker's Point is likely to be promoted by the recalcitrant litter of wind-adapted flora. This recalcitrant litter helps to explain widespread peatland development in a comparatively dry environment, and suggests that wind-adapted peatlands can remain carbon sinks even under low precipitation regimes.
VL - 34 TI - The Falkland Islands? palaeoecological response to millennial-scale climate perturbations during the Pleistocene?Holocene transition: implications for future vegetation stability in the southern ocean islands AV - public EP - 620 N1 - Funding Information: The Hooker's Point sequence, in conjunction with Holocene pollen records (Barrow,; Turney et al.,; and Thomas et al.,), show that the Falkland Islands have remained treeless for a least the last c. 16 500 years. The landscape of the Falkland Islands is, therefore, an unusual example of a maritime environment that has developed without trees and higher shrubs. This rare environmental history provides an interesting ecological control site that may be used for the study of fluvial development under temperate, treeless, conditions. Peatlands in the Falkland Islands have previously been considered to be relic systems that formed during wetter conditions in the past (Otley et al.,). However, continued organic accumulation at Hooker's Point throughout the Late-glacial demonstrates that Falkland Island peatlands have developed under dry conditions in the past, and may continue to do so today. This finding suggests that some peatlands in marginal environments can remain valuable carbon sinks even under low precipitation regimes. The vegetation of Hooker's Point appears insensitive to the regional cooling during the ACR, but shifted toward a dwarf shrub-dominated community during the latter half of the Younger Dryas time period and Southern Hemisphere Early Holocene Thermal Maximum. The decline of tussac grass dominance under warming has implications for future vegetation communities in the Falkland Islands which are expected to be subjected to a warmer climate. The first appearance of long-distance Nothofagus pollen in the Hooker's Point sequence c. 13 330 cal a bp is likely to be wind-dependant, and occurs late in the ACR. This time period is associated with changes in the strength and/or position of the Southern Westerly Wind Belt, and shifts in wind proxies in Laguna Potrok Aike (Mayr et al.,) and Tierra del Fuego (Mansilla et al.,) closely overlap the Nothofagus pollen record from Hooker's Point. Acknowledgements. We thank the Shackleton Scholarship Fund for a grant to enable fieldwork in the islands, as well as NE/1022981/1. We are grateful to the Falkland Islands Department of Mineral Resources who provided project support. Alex Blake assisted in sample collection from Hooker's Point. We would also like to thank Professor V. Jones (University College, London) who kindly examined diatoms from selected levels of the peat sequence. The comments of two anonymous reviews helped to improve the focus and clarity of this manuscript. Publisher Copyright: © 2019 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd. Y1 - 2019/10/08/ JF - Journal of Quaternary Science KW - Falkland Islands KW - island conservation KW - palaeoecology KW - peatland KW - Southern Westerly Wind Belt SN - 0267-8179 SP - 609 ER - TY - JOUR ID - soton49510 UR - https://eprints.soton.ac.uk/49510/ IS - 18-20 A1 - Seeyave, S. A1 - Lucas, M.I. A1 - Moore, C.M. A1 - Poulton, A.J. Y1 - 2007/// N2 - The CROZet natural iron bloom and EXport experiment (CROZEX) was carried out around the Crozet Plateau (Southern Ocean) in late austral spring-early summer 2004/2005. The primary aim of this study was to test the hypothesis that natural Fe fertilisation from the islands enhanced primary production to the north of the plateau, leading to elevated carbon export. During the 12-week shipboard study (November?January), size-fractionated chlorophyll-a (chl-a), primary productivity and phytoplankton pigments were determined at 20 stations around the Crozet Plateau, both inside and outside the expected bloom region. Satellite-derived chl-a data from August 2004 to April 2005 revealed that the cruise period covered the declining stage of a large phytoplankton bloom north of the Crozet Plateau. Productivity derived from satellite chl-a data showed a strong north?south gradient, with productivity reaching a maximum of 1.9 g C m?2 d?1 in the north (late October), 0.6 over the plateau (late March) and 0.4 in the south (early December). From November to early December, measured chl-a and productivity were still relatively high northwest of the plateau (54?74 mg chl-a m?2 and 0.5?1.1 g C m?2 d?1), the assemblage being dominated by Phaeocystis sp. and microplankton representing 50% of total chl-a. Declining biomass and productivity to the northwest in mid-December was associated with a picoplankton (52%) dominated community (19?38 mg chl-a m?2 and 0.1?0.4 g C m?2 d?1). In contrast, at the north eastern edge of the plateau, a mixed diatom/Phaeocystis dominated bloom (229 mg chl-a m?2 and 3 g C m?2 d?1) developed in mid-January. South of the plateau in the control high-nutrient low-chlorophyll (HNLC) region, biomass and productivity were always significantly lower, with only a small chl-a peak in December, and a community composed of microflagellates, cyanobacteria and some giant diatoms. Particulate organic carbon (POC):chl-a ratios provided physiological evidence for the impact of Fe fertilisation north of the plateau. The assimilation rate (i.e. integrated productivity normalised to integrated chl-a, ?P/?chl-a) did not show significant differences between the north and south, probably due to the late sampling period relative to the bloom peak. Overall, measurements of primary productivity during CROZEX supported the hypothesis of enhanced biomass and production due to natural iron enrichment of the region north of the Crozet Plateau, while south of the plateau, low biomass and productivity resulted primarily from Fe limitation. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 54 KW - Southern Ocean KW - Polar Frontal Zone (PFZ) KW - Crozet Islands KW - Phytoplankton KW - Primary productivity KW - Iron limitation SN - 0967-0645 TI - Phytoplankton productivity and community structure in the vicinity of the Crozet Plateau during austral summer 2004/2005 SP - 2020 AV - none EP - 2044 ER - TY - JOUR ID - soton43307 UR - https://eprints.soton.ac.uk/43307/ IS - 1 A1 - Serjeantson, Dale Y1 - 2005/04// N2 - A database of animal bone measurements, the Animal Bone Metrical Archive Project (ABMAP), is now available on the Web at http://ads.ahds.ac.uk/catalogue/specColl/abmap. The measurements can be downloaded and imported into a spreadsheet. They are of bones of domestic animals from the Neolithic to the 19 th century AD from assemblages in England, most from southern England. An example is given of the retrieval of measurements of cattle metacarpals and their application in a scatter diagram. The database is a resource for zooarchaeologists and others concerned with research into prehistoric and early historic domestic livestock and animal husbandry.Objective To analyze the epidemiological characteristics of human brucellosis in northern and southern areas of China, and to develop national strategies for bruceUosis prevention and control. Methods Individual data on human bruceUosis was collected from the National Notifiable Infectious Disease Reporting Information System to describe the situation of bruceUosis in China during 2015-2016. Epidemiological features of the disease in northern and southern areas of China were analyzed. Results A total of 104 125 cases were reported in mainland China during 2015-2016, with an average incidence rate as 3.81/100 000. The overall incidence rate from the northern provinces was 7.77/100 000 in 2016, a 18.6% decrease from 2015 (9.55/100 000), whereas the incidence rate in the southern provinces was 0.27/100 000 in 2016, with an increase of 28.6%% than 0.21/100 000 in 2015. 90.0% of the newly infected counties mainly distributed in southern China. As for the locations of reporting cases, most of them were in the same counties in the northern areas (52.3%) while most cases in the southern areas (59.6%) were imported from other counties. The median age of the cases was 48 (IQR: 38-58) years, with male-to-female ratios as 2.7 # 1 in the north and 2.2 : 1 in the south. Majority of the cases were occupation-related, from both the northern (86.8%) and southern (62.7%) areas. Human brucellosis occurred every month throughout the year but with an obvious seasonal increase between March and July. Conclusions Different epidemiological features of human bruceUosis appeared in both northern and southern areas of China. The disease was seen endemic in the northern and dispersal in the southern provinces. Appropriate strategies for bruceUosis prevention and control should be developed, according to the diiferent epidemiological characteristics in the northern or southern areas.
JF - Chinese Journal of Endemiology VL - 38 KW - Bruceuosis KW - China KW - Epidemiology KW - Northern and southern SN - 1000-4955 TI - Analysis on the epidemiological features of human brucellosis in northern and southern areas of China, 2015-2016 SP - 435 AV - none EP - 440 ER - TY - JOUR N1 - Funding Information: We would like to thank the captains, crew and scientists that were involved in collecting the cores used in this study, specifically captain Doug Monks and the crew of the RV Tangaroa who helped collect the TAN1106-28 core. The funding for the TAN1106 voyage was from the Coasts and Oceans Physical Resources program awarded to the National Institute of Water and Atmospheric Research, New Zealand (grant number COPR1703). We thank Bryn Taiapa and Geraldine Jacobsen (ANSTO) for additional radiocarbon data for core TAN1106-28, this work was funded by AINSE grant number ALNGRA15502 and Dr Samuel Toucanne (Ifremer) for providing a further radiocarbon date to improve the age modelling of the deglaciation. We also thank Andy Milton, Matt Cooper, and Megan Spencer as well as the rest of the Foster lab for laboratory assistance. This project was supported by the Natural Environment Research Council [NE/L002531/1] to R.S. and [NE/J021075/1] to G.L.F. Spanish Ministry of Science and Innovation [CGL2015-68194-R] to E.C. and C.P. S.L.J. acknowledges financial support from the Swiss National Science Foundation (SNSF grant PP00P2_172915), and A.M.-G. acknowledges funding from the Max Planck Society. Funding Information: We would like to thank the captains, crew and scientists that were involved in collecting the cores used in this study, specifically captain Doug Monks and the crew of the RV Tangaroa who helped collect the TAN1106-28 core. The funding for the TAN1106 voyage was from the Coasts and Oceans Physical Resources program awarded to the National Institute of Water and Atmospheric Research , New Zealand (grant number COPR1703 ). We thank Bryn Taiapa and Geraldine Jacobsen (ANSTO) for additional radiocarbon data for core TAN1106-28, this work was funded by AINSE grant number ALNGRA15502 and Dr Samuel Toucanne (Ifremer) for providing a further radiocarbon date to improve the age modelling of the deglaciation. We also thank Andy Milton, Matt Cooper, and Megan Spencer as well as the rest of the Foster lab for laboratory assistance. This project was supported by the Natural Environment Research Council [ NE/L002531/1 ] to R.S. and [ NE/J021075/1 ] to G.L.F., Spanish Ministry of Science and Innovation [ CGL2015-68194-R ] to E.C. and C.P., S.L.J. acknowledges financial support from the Swiss National Science Foundation (SNSF grant PP00P2_172915 ), and A.M.-G. acknowledges funding from the Max Planck Society . Publisher Copyright: © 2020 Elsevier B.V. ID - soton446395 UR - https://eprints.soton.ac.uk/446395/ A1 - Shuttleworth, R. A1 - Bostock, H.C. A1 - Chalk, T.B. A1 - Calvo, E. A1 - Jaccard, S.L. A1 - Pelejero, C. A1 - Garcia Martinez, A. A1 - Foster, G. Y1 - 2021/01/15/ N2 - Over the last deglaciation there were two transient intervals of pronounced atmospheric CO2 rise; Heinrich Stadial 1 (17.5-15 kyr) and the Younger Dryas (12.9-11.5 kyr). Leading hypotheses accounting for the increased accumulation of CO2 in the atmosphere at these times invoke deep ocean carbon being released from the Southern Ocean and an associated decline in the global efficiency of the biological carbon pump. Here we present new deglacial surface seawater pH and CO2sw records from the Sub-Antarctic regions of the Atlantic and Pacific oceans using boron isotopes measured on the planktic foraminifera Globigerina bulloides. These new data support the hypothesis that upwelling of carbon-rich water in the Sub-Antarctic occurred during Heinrich Stadial 1, and contributed to the initial increase in atmospheric CO2. The increase in CO2sw is coeval with a decline in biological productivity at both the Sub-Antarctic Atlantic and Pacific sites. However, there is no evidence for a significant outgassing of deep ocean carbon from the Sub-Antarctic during the rest of the deglacial, including the second period of atmospheric CO2 rise coeval with the Younger Dryas. This suggests that the second rapid increase in atmospheric CO2 is driven by processes operating elsewhere in the Southern Ocean, or another region. JF - Earth and Planetary Science Letters VL - 554 KW - CO flux KW - Heinrich Stadial 1 KW - Southern Ocean KW - Sub-Antarctic KW - boron isotopes KW - deglaciation SN - 0012-821X TI - Early deglacial CO2 release from the Sub-Antarctic Atlantic and Pacific oceans AV - public ER - TY - GEN N1 - Funding Information: The author(s) declare financial support was received for the research, authorship, and/or publication of this article. ASi acknowledges funding from NERC (NE/V014285/1). MB, CSt, and DF acknowledge funding from the New Zealand Strategic Science Investment Fund: Antarctic Science Platform Contract ANTA1801. SR and AF were supported by the Australian Antarctic Program Partnership (AAPP) through grant funding from the Australian Government as part of the Antarctic Science Collaboration Initiative program. AKM was supported by the Australian Research Council (ARC) Australian Centre for Excellence in Antarctic Science (SR200100008) and by the ARC Discovery Project DP190100494. EA, AJSM, MM acknowledge NERC grants NE/N018095/1 (ORCHESTRA), NE/V013254/1 (ENCORE), and NE/W004933/1 (BIOPOLE). This project has received funding from the European Union?s Horizon 2020 research and innovation program under grant agreement no. 821001. This research was supported by OCEAN:ICE, which is co-funded by the European Union, Horizon Europe Funding Programme for research and innovation under grant agreement no. 101060452 and by UK Research and Innovation. O:I Contribution number 1. FH was supported by the European Union (ERC, VERTEXSO, 101041743) and the Initiative and Networking Fund of the Helmholtz Association (Grant Number: VH-NG-19-33). WL was supported by the Korea Institute of Marine Science & Technology Promotion (KIMST) funded by the Ministry of Oceans and Fisheries (RS-2023-00256677; PM23020). Acknowledgments Publisher Copyright: Copyright © 2023 Silvano, Purkey, Gordon, Castagno, Stewart, Rintoul, Foppert, Gunn, Herraiz-Borreguero, Aoki, Nakayama, Naveira Garabato, Spingys, Akhoudas, Sallée, de Lavergne, Abrahamsen, Meijers, Meredith, Zhou, Tamura, Yamazaki, Ohshima, Falco, Budillon, Hattermann, Janout, Llanillo, Bowen, Darelius, Østerhus, Nicholls, Stevens, Fernandez, Cimoli, Jacobs, Morrison, Hogg, Haumann, Mashayek, Wang, Kerr, Williams and Lee. ID - soton485726 UR - https://eprints.soton.ac.uk/485726/ A1 - Silvano, Alessandro A1 - Purkey, Sarah A1 - Gordon, Arnold L. A1 - Castagno, Pasquale A1 - Stewart, Andrew A1 - Rintoul, Stephen A1 - Foppert, Annie A1 - Gunn, Kathryn L. A1 - Herraiz-Borreguero, Laura A1 - Aoki, Shigeru A1 - Nakayama, Yoshihiro A1 - Naveira Garabato, Alberto A1 - Spingys, Carl A1 - Akhoudas, Camille A1 - Sallee, Jean Baptiste A1 - de Lavergne, Casimir A1 - Abrahamsen, Povl A1 - Meijers, Andrew A1 - Meredith, Michael P. A1 - Zhou, Shenjie A1 - Tamura, Takeshi A1 - Yamazaki, Kaihe A1 - Ohshima, Kay A1 - Falco, Pierpaolo A1 - Budillon, Giorgio A1 - Hattermann, Tore A1 - Janout, Markus A. A1 - Llanillo, Pedro A1 - Bowen, Melissa A1 - Darelius, Elin A1 - Østerhus, Svein A1 - Nicholls, Keith A1 - Stevens, Craig A1 - Fernandez, Denise A1 - Cimoli, Laura A1 - Jacobs, Stanley S. A1 - Morrison, Adele A1 - Hogg, Andy A1 - Haumann, Alexander A1 - Mashayek, Ali A1 - Wang, Zhaomin A1 - Kerr, Rodrigo A1 - Williams, Guy D. A1 - Lee, Won Sang Y1 - 2023/// N2 -Dense, cold waters formed on Antarctic continental shelves descend along the Antarctic continental margin, where they mix with other Southern Ocean waters to form Antarctic Bottom Water (AABW). AABW then spreads into the deepest parts of all major ocean basins, isolating heat and carbon from the atmosphere for centuries. Despite AABW?s key role in regulating Earth?s climate on long time scales and in recording Southern Ocean conditions, AABW remains poorly observed. This lack of observational data is mostly due to two factors. First, AABW originates on the Antarctic continental shelf and slope where in situ measurements are limited and ocean observations by satellites are hampered by persistent sea ice cover and long periods of darkness in winter. Second, north of the Antarctic continental slope, AABW is found below approximately 2 km depth, where in situ observations are also scarce and satellites cannot provide direct measurements. Here, we review progress made during the past decades in observing AABW. We describe 1) long-term monitoring obtained by moorings, by ship-based surveys, and beneath ice shelves through bore holes; 2) the recent development of autonomous observing tools in coastal Antarctic and deep ocean systems; and 3) alternative approaches including data assimilation models and satellite-derived proxies. The variety of approaches is beginning to transform our understanding of AABW, including its formation processes, temporal variability, and contribution to the lower limb of the global ocean meridional overturning circulation. In particular, these observations highlight the key role played by winds, sea ice, and the Antarctic Ice Sheet in AABW-related processes. We conclude by discussing future avenues for observing and understanding AABW, impressing the need for a sustained and coordinated observing system.
KW - Antarctic Bottom Water (AABW) KW - Antarctic sea ice KW - ice shelves KW - observations KW - ocean freshening KW - ocean warming KW - Southern Ocean SN - 2296-7745 TI - Observing Antarctic Bottom Water in the Southern Ocean AV - public EP - 30 ER - TY - JOUR ID - soton348329 UR - https://eprints.soton.ac.uk/348329/ IS - 2 A1 - Smale, Dan A. A1 - Barnes, David K.A. A1 - Fraser, Keiron P.P. A1 - Mann, Paul J. A1 - Brown, Matt P. Y1 - 2007/10/19/ N2 - The response of scavengers to a feeding cue at Adelaide Island, West Antarctic Peninsula was investigated using a baited video camera system. Fourteen experimental deployments, each lasting 72 h were conducted at two contrasting sites during the winter and summer of 2005. The rate of bait consumption varied between sites but not between seasons, and was low in comparison with studies at lower latitudes and greater depths. At the Hangar Cove site, the nemertean Parborlasia corrugatus was out-competed at the bait and displaced by the lysianassid amphipod Cheirmedon femoratus during winter. However, C. femoratus did not feed on the bait during summer, allowing P. corrugatus to monopolise the feeding opportunity. At the South Cove site the asteroid Odontaster validus dominated the bait in both seasons but sporadic feeding by the nototheniid fish Notothenia coriiceps considerably affected consumption rates during two of the six deployments. Scavengers were attracted to the bait in very high numbers and opportunistic necrophagy seems to be a successful strategy in an environment that is intensely disturbed by ice. JF - Journal of Experimental Marine Biology and Ecology VL - 349 KW - baited camera KW - consumption rates KW - necrophagy KW - scavengers KW - southern ocean SN - 0022-0981 TI - Scavenging in Antarctica: intense variation between sites and seasons in shallow benthic necrophagy SP - 405 AV - none EP - 417 ER - TY - JOUR ID - soton15822 UR - http://www.agu.org/journals/jc/jc0405/2003JC002010/index.html IS - C5 A1 - Sokolov, S. A1 - King, B.A. A1 - Rintoul, S.R. A1 - Rojas, R.L. Y1 - 2004/// N2 - Repeat hydrographic sections across the Antarctic Circumpolar Current (ACC) in Drake Passage are used to derive an empirical relationship between upper ocean temperature and the baroclinic transport stream function. Cross validation shows this relationship can be used to infer baroclinic transport (above and relative to 2500 m) from expendable bathythermograph (XBT) temperature measurements with an error of a few per cent. Transport errors of less than 2 Sv are obtained if temperature at depths between 600 and 1600 m is used to define the relationship. Temperature at depths above 300 m provides an unreliable index of transport because of variability in temperature-salinity (T-S) properties produced by air-sea interaction. The scatter in the relationship between temperature and stream function from repeat observations along a single line is similar in magnitude to the scatter observed when data from the broader Drake Passage area are considered. In both cases, variability about the mean temperature-stream function relationship reflects advection of water with anomalous T-S properties. The tight relationship between temperature and stream function in Drake Passage and south of Australia suggests baroclinic transports can be inferred from XBT temperatures with high accuracy in the Southern Ocean, providing a cost-effective means of monitoring ACC variability. However, care must be taken at the end points, particularly in the Drake Passage where the strong flow of the Subantarctic Front sometimes lies over the continental slope. JF - Journal of Geophysical Research VL - 109 KW - Antarctic Circumpolar Current KW - baroclinic transport KW - Southern Ocean SN - 0148-0227 TI - Upper ocean temperature and the baroclinic transport stream function relationship in Drake Passage AV - none ER - TY - RPRT ID - soton15511 UR - https://eprints.soton.ac.uk/15511/ A1 - Sparrow, M. A1 - Hawker, E.J. Y1 - 2005/// N2 - This report describes the tenth occupation of the Drake Passage section, established during the World Ocean Circulation Experiment as repeat section SR1b. It was first occupied by Southampton Oceanography Centre in collaboration with the British Antarctic Survey in 1993, and has been re-occupied most years. Thirty-five full depth stations were completed, and 2 repeat shallow stations for biogeochemical sampling only. The full depth stations included a test station, the 30 stations for the SR1b Drake Passage section, with three repeat stations south of Burdwood Bank and one station in the ice in the Bellingshausen Sea for Dr. Mark Brandon. The CTD was a Sea-Bird 911plus with dual temperature and conductivity sensors, an altimeter, an oxygen sensor, a PAR (photosynthetically active radiation) sensor and a fluorometer. For 27 of the 30 SR1b stations LADCP data was also collected. The LADCP was a downward looking RDI Workhorse WH300 ADCP (WH) unit. Various underway measurements included navigation, VM-ADCP, sea surface temperature and salinity, water depth and meteorological parameters. PB - Southampton Oceanography Centre, University of Southampton T3 - 56 KW - Antarctic Circumpolar Current KW - Antarctic Ocean KW - ADCP KW - Acoustic Doppler Current Profiler KW - cruise 115 2004 KW - CTD Observations KW - Drake Passage KW - James Clark Ross KW - Lowered ADCP KW - LADCP KW - Southern Ocean KW - Vessel-Mounted ADCP KW - WOCE KW - World Ocean Circulation Experiment M1 - project_report TI - RRS James Clark Ross Cruise 115, 01 Dec-19 Dec 2004. Drake Passage repeat hydrography: WOCE Southern Repeat Section 1b - Burdwood Bank to Elephant Island AV - public EP - 80 ER - TY - JOUR ID - soton347640 UR - https://eprints.soton.ac.uk/347640/ IS - 12 A1 - St. Laurent, L. A1 - Naveira Garabato, A.C. A1 - Ledwell, J.R. A1 - Thurnherr, A.M. A1 - Toole, J.M. A1 - Watson, A.J. Y1 - 2012/// N2 - Direct measurements of turbulence levels in the Drake Passage region of the Southern Ocean show a marked enhancement over the Phoenix Ridge. At this site, the Antarctic Circumpolar Current (ACC) is constricted in its flow between the southern tip of South America and the northern tip of the Antarctic Peninsula. Observed turbulent kinetic energy dissipation rates are enhanced in the regions corresponding to the ACC frontal zones where strong flow reaches the bottom. In these areas, turbulent dissipation levels reach 10?8 W kg?1 at abyssal and middepths. The mixing enhancement in the frontal regions is sufficient to elevate the diapycnal turbulent diffusivity acting in the deep water above the axis of the ridge to 1 × 10?4 m2 s?1. This level is an order of magnitude larger than the mixing levels observed upstream in the ACC above smoother bathymetry. Outside of the frontal regions, dissipation rates are O(10?10) W kg?1, comparable to the background levels of turbulence found throughout most mid- and low-latitude regions of the global ocean. JF - Journal of Physical Oceanography VL - 42 KW - Southern Ocean KW - Turbulence KW - Diapycnal mixing SN - 0022-3670 TI - Turbulence and Diapycnal Mixing in Drake Passage SP - 2143 AV - none EP - 2152 ER - TY - RPRT ID - soton50065 UR - https://eprints.soton.ac.uk/50065/ A1 - Stansfield, K. A1 - Meredith, M. Y1 - 2008/01// N2 - This report describes the eleventh occupation of the Drake Passage section, establishedThe role of mesoscale turbulence in maintaining the mean buoyancy structure and overturning circulation of the Southern Ocean is investigated through a 2-year-long, single-mooring record of measurements in Drake Passage. The buoyancy budget of the area is successively assessed within the Eulerian and the Temporal-Residual-Mean frameworks. We find that a regime change occurs on time scales of 1 to 100 days, characteristic of mesoscale dynamics, whereby the eddy-induced turbulent horizontal advection balances the vertical buoyancy advection by the mean flow. We use these diagnostics to reconstruct the region's overturning circulation, which is found to entail an equatorward downwelling of Antarctic Intermediate and Bottom Waters and a poleward upwelling of Circumpolar Deep Water. The estimated eddy-induced flow can be accurately parameterized via the Gent-McWilliams closure by adopting a diffusivity of ?2,000 m 2 s ?1 with a middepth increase to 2,500 m 2 s ?1 at 2,100 m, immediately underneath the maximum interior stratification.
JF - Geophysical Research Letters VL - 46 KW - Eulerian circulation KW - meridional overturning KW - mesoscale turbulence KW - mooring measurements KW - residual-mean circulation KW - Southern Ocean SN - 0094-8276 TI - Observing the local emergence of the Southern Ocean residual-mean circulation SP - 3862 AV - public EP - 3870 ER - TY - JOUR ID - soton339742 UR - https://eprints.soton.ac.uk/339742/ IS - 17-18 A1 - Sévellec, Florian A1 - Fedorov, Alexey V. Y1 - 2011/09// N2 - The Atlantic Meridional Overturning Circulation (AMOC) is a crucial component of the global climate system. In this study, using a zonally averaged ocean model, we reexamine the sensitivity of this circulation, and ocean density structure in general, to several types of external forcing. The basin of the model extends from northern high latitudes to Antarctica and includes an implicit representation of a circumpolar channel in the South, and ocean circulation is driven by surface buoyancy fluxes and wind forcing. In contrast to earlier two-dimensional studies of the AMOC, our approach involves a careful treatment of the residual mean circulation (comprising the Eulerian-mean and eddy-induced flows), which is especially important for the Southern Ocean dynamics. Using boundary conditions consistent with present-day observations the model reproduces realistic ocean stratification and meridional overturning. The structure, intensity, and stability of the overturning are then extensively studied using three control parameters: the strength of westerly wind stress over the Southern Ocean, the magnitude of freshwater fluxes imposed on the northern Atlantic, and ocean diapycnal diffusivity. In a realistic parameter range, we estimate the AMOC sensitivity to changes in the Southern Ocean winds on the order of 1 Sv per 20% increase in the wind stress. The overturning also increases with diapycnal diffusivity, but the dependence is weaker than in the absence of the winds. The model can undergo a shutdown of the overturning (subject to a hysteresis) when either the freshwater forcing gradually increases or the wind stress decreases. The hysteresis loop disappears for large values of isopycnal diffusivity. Changes in the AMOC intensity are accompanied by changes in the volume transport of the Antarctic Circumpolar Current. Specifically, the AMOC collapse leads to a strengthening of this transport. Ultimately, our calculations produce stability maps for the steady states of the meridional overturning circulation and provide a general framework that potentially can be used to compare different models, or to understand past abrupt climate changes related to reorganization of the AMOC. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 58 KW - cean circulation KW - amoc KW - southern ocean KW - stability KW - hysteresis KW - freshwater fluxes SN - 0967-0645 TI - Stability of the Atlantic meridional overturning circulation and stratification in a zonally averaged ocean model: Effects of freshwater flux, Southern Ocean winds, and diapycnal diffusion SP - 1927 AV - none EP - 1943 ER - TY - JOUR N1 - Funding Information: We acknowledge Dr Bill Hiscock and Juee Vohra of UNSW MWAC for their work with radiocarbon dating. We would also like to acknowledge the families of Weddell Island, specifically Lewis Clifton, Stephen Clifton, Robert Short and Jo Turner, for facilitating and assisting with field work in the Falkland Islands. This work was supported by an ARC DECRA Fellowship (DE200100907) awarded to Dr Z. Thomas. ID - soton476752 UR - https://eprints.soton.ac.uk/476752/ A1 - Tamhane, Jamie A1 - Thomas, Zoë A. A1 - Cadd, Haidee A1 - Harris, Matthew R.P. A1 - Turney, Chris A1 - Marjo, Christopher E. A1 - Wang, Huixin A1 - Akter, Rabeya A1 - Panaretos, Panayiotis A1 - Halim, Amalia A1 - Gadd, Patricia S. A1 - Carter, Stefanie A1 - Brickle, Paul Y1 - 2023/04/01/ N2 -The Southern Hemisphere westerly winds (SWW), a belt of strong zonal winds in the mid-latitudes, play a key role in Southern Hemisphere climate variability. Recent intensification and southwards migration of the SWW is projected to continue due to anthropogenic climate change and despite a recovering Antarctic ozone hole, impacting regional hydroclimate, ocean circulation and carbon cycling. Despite the importance of the SWW, our understanding of their behaviour on centennial to millennial timescales is limited by the inherently short observational record and limited palaeo-archive agreement on the wind belt's Holocene dynamics. Here we utilise dust flux, Itrax core scanning, rare earth element composition and HYSPLIT particle modelling to present a 8700-year (10,500?1700 cal yr BP) reconstruction of local SWW intensity from a Falkland Islands (Islas Malvinas) peat sediment core which, along with other reconstructions, we interpret in a regional South Atlantic and hemispheric context. We find increased dust deposition and variability from ca. 5700 cal yr BP, signalling an intensification and possible southwards shift of the SWW, though Patagonia likely remains the primary distal dust source throughout our record. Additionally, we identify asymmetric behaviour in the SWW belt from 3000 to 1700 cal yr BP over southern South America and the southwest Atlantic. In alignment with these findings, we propose a possible eastwards projection of the Amundsen Sea Low (ASL) into the South Atlantic during this period. Two volcanic eruptions, likely from Mt Burney (ca. 9700 cal yr BP) and Mt Hudson (ca. 4100 cal yr BP), are captured as cryptotephra deposits in the record. Our precisely dated, high-resolution multiproxy record of South Atlantic wind-blown transport provides an important new dataset that accurately constrains SWW Holocene variability over the Falkland Islands.
JF - Quaternary Science Reviews VL - 305 KW - Amundsen Sea Low KW - cryptotephra KW - dust KW - Falkland Islands KW - HYSPLIT KW - Itrax KW - peat KW - radiocarbon dating KW - rare earth elements KW - Southern Hemisphere westerly winds SN - 0277-3791 TI - Mid-Holocene intensification of Southern Hemisphere westerly winds and implications for regional climate dynamics AV - public EP - 14 ER - TY - JOUR ID - soton336382 UR - https://eprints.soton.ac.uk/336382/ A1 - Tarling, G.A. A1 - Stowasser, G. A1 - Ward, P. A1 - Poulton, A.J. A1 - Zhou, M. A1 - Venables, H.J. A1 - McGill, R.A.R. A1 - Murphy, E.J. Y1 - 2012/01// N2 - The biomass size structure of pelagic communities provides a system level perspective that can be instructive when considering trophic interactions. Such perspectives can become even more powerful when combined with taxonomic information and stable isotope analysis. Here we apply these approaches to the pelagic community of the Scotia Sea (Southern Ocean) and consider the structure and development of trophic interactions over different years and seasons. Samples were collected from three open-ocean cruises during the austral spring 2006, summer 2008 and autumn 2009. Three main sampling techniques were employed: sampling bottles for microplankton (0?50 m), vertically hauled fine meshed nets for mesozooplankton (0?400 m) and coarse-meshed trawls for macrozooplankton and nekton (0?1000 m). All samples were identified to the lowest practicable taxonomic level and their abundance, individual body weight and biomass (in terms of carbon) estimated. Slopes of normalised biomass spectrum versus size showed a significant but not substantial difference between cruises and were between ?1.09 and ?1.06. These slopes were shallower than expected for a community at equilibrium and indicated that there was an accumulation of biomass in the larger size classes (101?105 mg C ind?1). A secondary structure of biomass domes was also apparent, with the domes being 2.5?3 log10 intervals apart in spring and summer and 2 log10 intervals apart in autumn. The recruitment of copepod-consuming macrozooplankton, Euphausia triacantha and Themisto gaudichaudii into an additional biomass dome was responsible for the decrease in the inter-dome interval in autumn. Predator to prey mass ratios estimated from stable isotope analysis reached a minimum in autumn while the estimated trophic level of myctophid fish was highest in that season. This reflected greater amounts of internal recycling and increased numbers of trophic levels in autumn compared to earlier times of the year. The accumulation of biomass in larger size classes throughout the year in the Scotia Sea may reflect the prevalence of species that store energy and have multiyear life-cycles. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 59-60 KW - Southern Ocean KW - Phytoplankton KW - Zooplankton KW - Nekton KW - Myctophids KW - Predator?prey interactions SN - 0967-0645 TI - Seasonal trophic structure of the Scotia Sea pelagic ecosystem considered through biomass spectra and stable isotope analysis SP - 222 AV - none EP - 236 ER - TY - JOUR ID - soton351002 UR - https://eprints.soton.ac.uk/351002/ IS - 3-4 A1 - Terray, Pascal A1 - Kamala, Kakitha A1 - Masson, Sébastien A1 - Madec, Gurvan A1 - Sahai, A.K. A1 - Luo, Jing-Jia A1 - Yamagata, Toshio Y1 - 2012/08// N2 - The impact of diurnal SST coupling and vertical oceanic resolution on the simulation of the Indian Summer Monsoon (ISM) and its relationships with El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) events are studied through the analysis of four integrations of a high resolution Coupled General Circulation Model (CGCM), but with different configurations. The only differences between the four integrations are the frequency of coupling between the ocean and atmosphere for the Sea Surface Temperature (SST) parameter (2 vs. 24 h coupling) and/or the vertical oceanic resolution (31 vs. 301 levels) in the CGCM. Although the summer mean tropical climate is reasonably well captured with all the configurations of the CGCM and is not significantly modified by changing the frequency of SST coupling from once to twelve per day, the ISM?ENSO teleconnections are rather poorly simulated in the two simulations in which SST is exchanged only once per day, independently of the vertical oceanic resolution used in the CGCM. Surprisingly, when 2 h SST coupling is implemented in the CGCM, the ISM?ENSO teleconnection is better simulated, particularly, the complex lead-lag relationships between the two phenomena, in which a weak ISM occurs during the developing phase of an El Niño event in the Pacific, are closely resembling the observed ones. Evidence is presented to show that these improvements are related to changes in the characteristics of the model?s El Niño which has a more realistic evolution in its developing and decaying phases, a stronger amplitude and a shift to lower frequencies when a 2-hourly SST coupling strategy is implemented without any significant changes in the basic state of the CGCM. As a consequence of these improvements in ENSO variability, the lead relationships between Indo-Pacific SSTs and ISM rainfall resemble the observed patterns more closely, the ISM?ENSO teleconnection is strengthened during boreal summer and ISM rainfall power spectrum is in better agreement with observations. On the other hand, the ISM?IOD teleconnection is sensitive to both SST coupling frequency and the vertical oceanic resolution, but increasing the vertical oceanic resolution is degrading the ISM?IOD teleconnection in the CGCM. These results highlight the need of a proper assessment of both temporal scale interactions and coupling strategies in order to improve current CGCMs. These results, which must be confirmed with other CGCMs, have also important implications for dynamical seasonal prediction systems or climate change projections of the monsoon. JF - Climate Dynamics VL - 39 KW - Indian summer monsoon El Niño-Southern Oscillation Intra-daily SST variability Ocean?atmosphere interactions Coupled climate model SN - 0930-7575 TI - The role of the intra-daily SST variability in the Indian monsoon variability and monsoon-ENSO?IOD relationships in a global coupled model SP - 729 AV - none EP - 754 ER - TY - JOUR ID - soton38985 UR - https://eprints.soton.ac.uk/38985/ IS - 2 A1 - Thatje, S. A1 - Lovrich, G.A. A1 - Torres, G. A1 - Hagen, W. A1 - Anger, K. Y1 - 2004/04/15/ N2 - Ontogenetic changes in biomass and chemical composition were studied in the laboratory during the abbreviated larval and early juvenile development of the caridean shrimp Campylonotus vagans from the subantarctic Beagle Channel, Argentina. At 7±0.5 °C, development from hatching to metamorphosis took about 44 days. The larvae started feeding on Artemia nauplii immediately after hatching, although larval resistance to starvation was high (average 18 days, maximum 29 days). Dry mass (DM), carbon (C), nitrogen (N) and hydrogen (H) contents increased about a fourfold from hatching to metamorphosis, while the C:N mass ratio increased from about 3.7 to 4.3. The protein and total lipid contents increased gradually from hatching to the first juvenile stage, the former from 190 to 640 ?g/individual, the latter from 37 to 95 ?g/individual. The lipid mass fraction was low throughout larval development (3?9% of DM), while the protein content was much higher and almost constant (30?40%). The dominating fatty acids were 18:1(n-9), 16:0, 20:5(n-3), 18:1(n-7), 18:3(n-3), 18:0, 16:1(n-7). Except for 20:5(n-3), these resulted mainly from food uptake (Artemia nauplii). Exuvial losses of C, H and N (all larval stages combined) accounted for only 7%, 1% and 1% of the initial values at hatching. In contrast, 37% of initial DM was lost. Partially food-independent (endotrophic) larval development is discussed as an adaptation to food scarcity at high latitudes, while the abbreviated planktotrophic larval development appears to be synchronised with seasonal peaks in primary production, allowing for an optimal resource exploitation in a food-limited environment.Occurrences of killer whales (Orcinus orca) in the waters surrounding Sub-Antarctic Macquarie Island have been recorded since the 1820s; however, their presence only became the focus of scientific research in the mid-1990s. The analyses of sightings data collected from the island between 1986 and 2015 are presented herein. The study provides evidence of a relationship between killer whale sighting probability and seasonal prey availability. Killer whales were present at the island year-round with a distinct seasonal peak in November?December, and coincident with a peak in occurrence of southern elephant seals (Mirounga leonina) due to breeding season activity, particularly the dispersal of weaned pups. Supporting this association and killer whales? top-down influence on the survival of juvenile and adult southern elephant seals, pinnipeds accounted for 79% of prey identified, with weaned southern elephant seal pups contributing over a quarter of feeding events observed in the near-shore environment. Fur seals and penguins were also identified as prey. Killer whale groups had a median group size of three individuals, and groups of three to five individuals were most often observed feeding/milling in near-shore waters. The largest range in group sizes were observed during their peak occurrence in early summer, particularly in the number of sub-adult and female whales per group. Adult males made up 75% of single occurrences, and singletons were most often observed travelling. Overall, the ecology of killer whales at Macquarie Island was similar to that of killer whales studied at other Sub-Antarctic locations, with comparable seasonality, behaviour, diet, and group structure. Much remains to be learnt regarding the seasonal movements of whales and their diet at other times of year, their relationship to killer whales sighted in coastal Australian, New Zealand and Antarctic ecosystems, and impact on diet from commercial fisheries operations and fluctuating prey populations.
JF - Polar Biology VL - 41 KW - Diet KW - Feeding behaviour KW - Group size KW - Southern elephant seal SN - 0722-4060 TI - Aspects of the ecology of killer whale (Orcinus orca Linn.) groups in the near-shore waters of Sub-Antarctic Macquarie Island SP - 2249 AV - none EP - 2259 ER - TY - JOUR ID - soton476049 UR - https://eprints.soton.ac.uk/476049/ IS - 3 A1 - Turney, C. S.M. A1 - Wilmshurst, J. M. A1 - Jones, R. T. A1 - Wood, J. R. A1 - Palmer, J. G. A1 - Hogg, A. G. A1 - Fenwick, P. A1 - Crowley, S. F. A1 - Privat, K. A1 - Thomas, Z. N2 - Late-twentieth century changes in the intensity and migration of Southern Hemisphere westerly winds have been implicated in spatially complex variability in atmospheric and ocean circulation, and ice-sheet dynamics, across the mid- to high-latitudes. A major uncertainty, however, is whether present day hemispheric-wide symmetrical airflow is representative of past behaviour. Here we report a multi-proxy study from Stewart Island and southern Fiordland, New Zealand (46?47°S) reconstructing Holocene changes at the northern limit of westerly airflow. Increased minerogenic input and a pronounced shift in cool-loving vegetation around 5500 years ago is consistent with the establishment of westerly airflow at this latitude in the southwest Pacific. In marked contrast, stronger winds are reported further south over the subantarctic Auckland (50°S) and Campbell (52°S) Islands from 8000 years ago. Intriguingly, reconstructions from the east Pacific suggest a weakening of core westerly airflow after 8500 years ago, but an expansion along the northern limits sometime after 5500 years ago. Our results suggest similar atmospheric circulation changes have been experienced in the Pacific since 5500 years ago, but indicate an expanded network of sites is needed to comprehensively test the driver(s) and impact(s) of Holocene mid-latitude westerly winds across the Southern Hemisphere. VL - 159 TI - Reconstructing atmospheric circulation over southern New Zealand: Establishment of modern westerly airflow 5500 years ago and implications for Southern Hemisphere Holocene climate change AV - none EP - 87 N1 - Publisher Copyright: © 2016 Elsevier Ltd Y1 - 2017/03/01/ JF - Quaternary Science Reviews KW - Jet stream KW - Roaring Forties KW - Southern Annular Mode (SAM) KW - Southern Hemisphere westerly winds KW - Southern Ocean KW - Wind-blown sediments SN - 0277-3791 SP - 77 ER - TY - JOUR N1 - Publisher Copyright: © 2016 IOP Publishing Ltd. ID - soton476046 UR - https://eprints.soton.ac.uk/476046/ IS - 6 A1 - Turney, Chris S.M. A1 - Jones, Richard T. A1 - Lister, David A1 - Jones, Phil A1 - Williams, Alan N. A1 - Hogg, Alan A1 - Thomas, Zoë A. A1 - Compo, Gilbert P. A1 - Yin, Xungang A1 - Fogwill, Christopher J. A1 - Palmer, Jonathan A1 - Colwell, Steve A1 - Allan, Rob A1 - Visbeck, Martin Y1 - 2016/06/09/ N2 - Determining the timing and impact of anthropogenic climate change in data-sparse regions is a considerable challenge. Arguably, nowhere is this more difficult than the Antarctic Peninsula and the subantarctic South Atlantic where observational records are relatively short but where high rates of warming have been experienced since records began. Here we interrogate recently developed monthly-resolved observational datasets from the Falkland Islands and South Georgia, and extend the records back using climate-sensitive peat growth over the past 6000 years. Investigating the subantarctic climate data with ERA-Interim and Twentieth Century Reanalysis, we find that a stepped increase in precipitation across the 1940s is related to a change in synoptic atmospheric circulation: a westward migration of quasi-permanent positive pressure anomalies in the South Atlantic has brought the subantarctic islands under the increased influence of meridional airflow associated with the Amundsen Sea Low. Analysis of three comprehensively multi-dated (using 14C and 137Cs) peat sequences across the two islands demonstrates unprecedented growth rates since the mid-twentieth century relative to the last 6000 years. Comparison to observational and reconstructed sea surface temperatures suggests this change is linked to a warming tropical Pacific Ocean. Our results imply 'modern' South Atlantic atmospheric circulation has not been under this configuration for millennia. JF - Environmental Research Letters VL - 11 KW - anthropogenic climate change KW - climate reanalysis KW - El Niño-Southern Oscillation (ENSO) KW - southern annular mode (SAM) KW - Southern Hemisphere westerlies KW - subantarctic climate extremes KW - temperature SN - 1748-9318 TI - Anomalous mid-twentieth century atmospheric circulation change over the South Atlantic compared to the last 6000 years AV - none ER - TY - JOUR ID - soton479325 UR - https://eprints.soton.ac.uk/479325/ IS - 1 A1 - Turney, Chris S.M. A1 - McGlone, Matt A1 - Palmer, Jonathan A1 - Fogwill, Christopher A1 - Hogg, Alan A1 - Thomas, Zoë A. A1 - Lipson, Mathew A1 - Wilmshurst, Janet M. A1 - Fenwick, Pavla A1 - Jones, Richard T. A1 - Hines, Ben A1 - Clark, Graeme F. N2 -The Southern Ocean plays a significant role in driving global climate-ocean-carbon dynamics. Unfortunately, a relative dearth of datasets across the region limits our ability to understand past and future mechanisms of change. Here we report a new dataset from the south-west Pacific: radiocarbon-dated subfossil tree stumps (Dracophyllum) eroding out from peat exposures on Campbell and Auckland Islands (52-50°S). Dracophyllum are the southernmost growing trees in the south-west Pacific and their growth on exposed sites and at altitude is strongly controlled by the prevailing westerly airflow, providing a unique measure of past changes in zonal wind strength. Here we demonstrate a significant collapse in the altitudinal limit of growth between approximately 2000 and 1000 years ago (hereafter 2-1ka), consistent with other records across the Southern Hemisphere that indicate westerly airflow was significantly enhanced. Importantly, this period in the late Holocene was one of marked change across the broader region, suggesting westerly airflow played a key role in driving Southern Ocean variability at this time.
VL - 31 TI - Intensification of Southern Hemisphere westerly winds 2000-1000 years ago: Evidence from the subantarctic Campbell and Auckland Islands (52-50°S) AV - none EP - 19 N1 - Publisher Copyright: © 2016 John Wiley & Sons, Ltd. Y1 - 2016/01/08/ JF - Journal of Quaternary Science KW - Southern Hemisphere westerlies KW - Southern Ocean KW - Subantarctic islands KW - Subfossil trees KW - Tree line SN - 0267-8179 SP - 12 ER - TY - JOUR ID - soton476055 UR - https://eprints.soton.ac.uk/476055/ IS - 2 A1 - Turney, Chris S.M. A1 - Palmer, Jonathan A1 - Hogg, Alan A1 - Fogwill, Christopher J. A1 - Jones, Richard T. A1 - Bronk Ramsey, Christopher A1 - Fenwick, Pavla A1 - Grierson, Pauline A1 - Wilmshurst, Janet A1 - O'Donnell, Alison A1 - Thomas, Zoë A. A1 - Lipson, Mathew N2 - Northern Hemisphere-wide cooling during the Little Ice Age (LIA; 1650-1775 Common Era, C.E.) was associated with a ~5 ppmv decrease in atmospheric carbon dioxide. Changes in terrestrial and ocean carbon reservoirs have been postulated as possible drivers of this relatively large shift in atmospheric CO2, potentially providing insights into the mechanisms and sensitivity of the global carbon cycle. Here we report decadally resolved radiocarbon (14C) levels in a network of tree-ring series spanning 1700-1950 C.E. located along the northern boundary of, and within, the Southern Ocean. We observe regional dilutions in atmospheric radiocarbon (relative to the Northern Hemisphere) associated with upwelling of 14CO2-depleted abyssal waters. We find the interhemispheric 14C offset approaches zero during increasing global atmospheric CO2 at the end of the LIA, with reduced ventilation in the Southern Ocean and a Northern Hemisphere source of old carbon (most probably originating from deep Arctic peat layers). The coincidence of the atmospheric CO2 increase and reduction in the interhemispheric 14C offset imply a common climate control. Possible mechanisms of synchronous change in the high latitudes of both hemispheres are discussed. VL - 30 TI - Multidecadal variations in Southern Hemisphere atmospheric 14C: Evidence against a Southern Ocean sink at the end of the Little Ice Age CO2 anomaly AV - none EP - 218 N1 - Funding Information: C.S.M.T., C.F., and P.G. acknowledge the support of the Australian Research Council (FL100100195, FT120100004, and DP130104156). Publisher Copyright: ©2016. American Geophysical Union. All Rights Reserved. Y1 - 2016/02// JF - Global Biogeochemical Cycles KW - interhemispheric gradient (IHG) KW - Little Ice Age (LIA) KW - radiocarbon (C) KW - Southern Hemisphere carbon dioxide (CO) KW - Southern Ocean KW - tree rings SN - 0886-6236 SP - 211 ER - TY - RPRT ID - soton19296 UR - https://eprints.soton.ac.uk/19296/ Y1 - 2001/12// PB - International CLIVAR Project Office T3 - No. 22 (Vol. 6(4) KW - CLIVAR KW - WCRP KW - Exchanges KW - Newsletter KW - Southern Ocean Climate Variability ED - Villwock, A. ED - Gould, J. M1 - project_report TI - CLIVAR Exchanges No. 22. Special issue on: Southern Ocean Climate Variability AV - public EP - 36 ER - TY - JOUR ID - soton174075 UR - https://eprints.soton.ac.uk/174075/ IS - 9-10 A1 - Vincent, Emmanuel M. A1 - Lengaigne, Matthieu A1 - Menkes, Christophe E. A1 - Jourdain, Nicolas C. A1 - Marchesiello, Patrick A1 - Madec, Gurvan Y1 - 2011/// N2 - The interannual variability of the South Pacific Convergence Zone (SPCZ) and its influence on tropical cyclone (TC) genesis in the South Pacific are investigated using observations and ERA40 reanalysis over the 1979?2002 period. In austral summer, the SPCZ displays four typical structures at interannual timescales. The first three are characterized by a diagonal orientation of the SPCZ and account for 85% of the summer seasons. One is close to climatology and the other two exhibit a 3° northward or southward departure from the SPCZ climatological position. In contrast, the fourth one, that only encompasses three austral summer seasons (the extreme 1982/1983 and 1997/1998 El Niño events and the moderate 1991/1992 El Niño event), displays very peculiar behaviour where the SPCZ largely departs from its climatological position and is zonally oriented. Variability of the western/central Pacific equatorial sea surface temperature (SST) is shown to modulate moisture transport south of the equator, thereby strongly constraining the location of the SPCZ. The SPCZ location is also shown to strongly modulate the atmospheric circulation variability in the South Pacific with specific patterns for each class. However, independently of its wide year-to-year excursions, the SPCZ is always collocated with the zero relative vorticity at low levels while the maximum vorticity axis lies 6° to the south of the SPCZ position. This coherent atmospheric organisation in the SPCZ region is shown to constrain tropical cyclogenesis to occur preferentially within 10° south of the SPCZ location as this region combines all the large-scale atmospheric conditions that favour the breeding of TCs. This analysis also reveals that cyclogenesis in the central Pacific (in the vicinity of French Polynesia) only occurs when the SPCZ displays a zonal orientation while this observation was previously attributed to El Niño years in general. Different characteristics of El Niño Southern Oscillation (ENSO)-related Pacific equatorial warming are shown to impact differently on the SPCZ position, suggesting that for regional scales, such as the South Pacific, the SPCZ classification is more appropriate than a simple ENSO index to characterize TC interannual variability. These findings suggest that forecasting the strength of El Niño through SST variations in the eastern Pacific may not be sufficient to accurately predict cyclogenesis in the South Pacific, especially east of the dateline. JF - Climate Dynamics VL - 36 KW - South Pacific Convergence Zone KW - Interannual variability KW - Tropical cyclone KW - El Niño Southern Oscillation SN - 0930-7575 TI - Interannual variability of the South Pacific Convergence Zone and implications for tropical cyclone genesis SP - 1881 AV - none EP - 1896 ER - TY - JOUR ID - soton340156 UR - https://eprints.soton.ac.uk/340156/ IS - 7 A1 - Völker, David A1 - Geersen, Jacob A1 - Contreras-Reyes, Eduardo A1 - Sellanes, Javier A1 - Pantoja, Silvio A1 - Rabbel, Wolfgang A1 - Thorwart, Martin A1 - Reichert, Christian A1 - Block, Martin A1 - Weinrebe, Wilhelm Reimer Y1 - 2014/10// N2 - The continental shelf and slope of southern Central Chile have been subject to a number of international as well as Chilean research campaigns over the last 30 years. This work summarizes the geologic setting of the southern Central Chilean Continental shelf (33°S?43°S) using recently published geophysical, seismological, sedimentological and bio-geochemical data. Additionally, unpublished data such as reflection seismic profiles, swath bathymetry and observations on biota that allow further insights into the evolution of this continental platform are integrated. The outcome is an overview of the current knowledge about the geology of the southern Central Chilean shelf and upper slope. We observe both patches of reduced as well as high recent sedimentation on the shelf and upper slope, due to local redistribution of fluvial input, mainly governed by bottom currents and submarine canyons and highly productive upwelling zones. Shelf basins show highly variable thickness of Oligocene-Quaternary sedimentary units that are dissected by the marine continuations of upper plate faults known from land. Seismic velocity studies indicate that a paleo-accretionary complex that is sandwiched between the present, relatively small active accretionary prism and the continental crust forms the bulk of the continental margin of southern Central Chile. JF - International Journal of Earth Sciences VL - 103 KW - Southern Central Chile KW - Bathymetry KW - Shelf sedimentation KW - Shelf basins KW - Submarine faults KW - Seismicity KW - Fluid seepage SN - 1437-3254 TI - Morphology and geology of the continental shelf and upper slope of southern Central Chile (33°S?43°S) SP - 1765 AV - none EP - 1787 ER - TY - JOUR ID - soton363144 UR - https://eprints.soton.ac.uk/363144/ IS - 7 A1 - Völker, David A1 - Wehrmann, Heidi A1 - Kutterolf, Steffen A1 - Iyer, Karthik A1 - Rabbel, Wolfgang A1 - Geersen, Jacob A1 - Hoernle, Kaj Y1 - 2014/10// N2 - In this paper, we constrain the input and output fluxes of H2O, Cl and S into the southern-central Chilean subduction zone (31°S?46°S). We determine the input flux by calculating the amounts of water, chlorine and sulfur that are carried into the subduction zone in subducted sediments, igneous crust and hydrated lithospheric mantle. The applied models take into account that latitudinal variations in the subducting Nazca plate impact the crustal porosity and the degree of upper mantle serpentinization and thus water storage in the crust and mantle. In another step, we constrain the output fluxes of the subduction zone both to the subcontinental lithospheric mantle and to the atmosphere?geosphere?ocean by the combined use of gas flux determinations at the volcanic arc, volume calculations of volcanic rocks and the combination of mineralogical and geothermal models of the subduction zone. The calculations indicate that about 68 Tg/m/Ma of water enters the subduction zone, as averaged over its total length of 1,480 km. The volcanic output on the other hand accounts for 2 Tg/m/Ma or 3 % of that input. We presume that a large fraction of the volatiles that are captured within the subducting sediments (which accounts for roughly one-third of the input) are cycled back into the ocean through the forearc. This assumption is however questioned by the present lack of evidence for major venting systems of the submarine forearc. The largest part of the water that is carried into the subduction zone in the crust and hydrated mantle (accounting for two-thirds of the input) appears to be transported beyond the volcanic arc. JF - International Journal of Earth Sciences VL - 103 KW - Subduction input KW - Forearc dewatering KW - Arc magmatism KW - Volcanic volatile output rates KW - Subduction fluids KW - Southern volcanic zone of Chile SN - 1437-3254 TI - Constraining input and output fluxes of the southern-central Chile subduction zone: water, chlorine and sulfur SP - 2129 AV - none EP - 2153 ER - TY - INPR ID - soton455079 UR - https://eprints.soton.ac.uk/455079/ A1 - Ward, Ingrid A1 - Bastos, Alex A1 - Carabias, Diego A1 - Cawthra, Hayley A1 - Farr, Helen A1 - Green, Andrew A1 - Sturt, Fraser Y1 - 2022/01/14/ N2 - The potential of submerged palaeolandscapes to address questions about global migrations, broad-scale climate and landscape change, and human response to this has to date been concentrated in the Northern Hemisphere (NH). The Southern Hemisphere (SH) has less land, more water and water barriers, higher floral and faunal endemicity, lower population but with Indigenous populations that have maintained a connection with coastal and offshore landscapes for at least 40,000 years in Australasia, and almost 170,000 years in South Africa. We provide an overview of current knowledge in South America, Southern Africa and Australasia and explore how new palaeogeographic and palaeoecological research, alongside related coastal archaeology, is helping to map out future directions for submerged cultural landscape research in these regions. A common theme across is the need to raise awareness of submerged cultural resources and Indigenous knowledge of these as well as the multi-disciplinary approach needed to understand the unique landscapes in which they are preserved. KW - Submerged Palaeolandscape KW - Southern Hemisphere TI - Submerged Palaeolandscapes of the Southern Hemisphere (SPLOSH) - What is emerging from the Southern Hemisphere AV - restricted EP - 24 ER - TY - JOUR ID - soton190541 UR - https://eprints.soton.ac.uk/190541/ IS - 3-4 A1 - Watt, Sebastian F.L. A1 - Pyle, David M. A1 - Mather, Tamsin A. Y1 - 2009/01/30/ N2 - Seismic activity has been postulated as a trigger of volcanic eruption on a range of timescales, but demonstrating the occurrence of triggered eruptions on timescales beyond a few days has proven difficult using global datasets. Here, we use the historic earthquake and eruption records of Chile and the Andean southern volcanic zone to investigate eruption rates following large earthquakes. We show a significant increase in eruption rate following earthquakes of MW > 8, notably in 1906 and 1960, with similar occurrences further back in the record. Eruption rates are enhanced above background levels for ~ 12 months following the 1906 and 1960 earthquakes, with the onset of 3?4 eruptions estimated to have been seismically influenced in each instance. Eruption locations suggest that these effects occur from the near-field to distances of ~ 500 km or more beyond the limits of the earthquake rupture zone. This suggests that both dynamic and static stresses associated with large earthquakes are important in eruption-triggering processes and have the potential to initiate volcanic eruption in arc settings over timescales of several months. JF - Earth and Planetary Science Letters VL - 277 KW - seismic triggering KW - volcanic eruption KW - Chile KW - Andean southern volcanic zone KW - great earthquake KW - eruption rates SN - 0012-821X TI - The influence of Great Earthquakes on volcanic eruption rate along the Chilean subduction zone SP - 399 AV - none EP - 407 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 N1 - Funding Information: Sea time and logistics for the Five Deeps Expedition were supported and funded by Victor Vescovo of Caladan Oceanic LLC (United States). DNA barcoding was funded by the ?Hadal Zones of Our Overseas Territories? by the Darwin Initiative funded by the UK Government ( DPLUS093 ) awarded to HAS . AJJ and PJM are supported by the Minderoo-UWA Deep-Sea Research Centre funded by the Minderoo Foundation , Australia, and JNJW through the Townsend Postdoctoral Scholarship Fund through the Woods Hole Oceanographic Institution , USA. ID - soton481648 UR - https://eprints.soton.ac.uk/481648/ A1 - Weston, Johanna N.J. A1 - Stewart, Eva C.D. A1 - Maroni, Paige J. A1 - Stewart, Heather A. A1 - Jamieson, Alan J. Y1 - 2023/06// N2 -Cryptic species in the deep ocean are rapidly being identified with molecular evidence and as a result, new species are being described. Consequently, our understanding of distributions among the revised landscape of species needs to be reassessed. A model example is the large scavenging amphipod, Eurythenes gryllus (Lichtenstein in Mandt, 1882), which historically was thought to have a eurybathic and cosmopolitan distribution. Molecular evidence has since led to the separation of E. gryllus into ten named species and truncating its range to bi-polar bathyal depths. This study focuses on two species; Eurythenes sigmiferus and Eurythenes andhakarae d'Udekem d'Acoz and Havermans, 2015, and presents new records of both species from 5,493 m in the previously unsampled Agulhas Fracture Zone, South Atlantic Ocean (42.77°S, 10.05°E). We paired morphology with DNA barcoding at two mitochondrial regions to achieve robust identification and assessed their wider geographic range by reassessing historical records. Their overlapping presence at the Agulhas Fracture Zone expands their known ranges to the non-polar South Atlantic Ocean. Specifically, for E. sigmiferus, the data suggests this species has a multi-ocean tropical to temperate distribution from abyssal to shallow hadal depths (3,410?6,097 m). Eurythenes andhakarae is not restricted to the Southern Ocean but is distributed across the Antarctic Polar Front to the temperate South Atlantic Ocean between abyssal and hadal depths (3,069?7,099 m), with a presence at bathyal depths requiring molecular confirmation. This study highlights that pairing new expeditions with a re-inspection of rich historical collections exploration can fill in data gaps across species ranges and, ultimately, biogeography.
JF - Deep-Sea Research Part I: Oceanographic Research Papers VL - 196 KW - Amphipoda KW - Antarctic polar front KW - Cryptic species KW - Deep sea KW - DNA barcoding KW - Historical collections KW - New records KW - Southern ocean SN - 0967-0637 TI - Eurythenes sigmiferus and Eurythenes andhakarae (Crustacea Amphipoda) are sympatric at the abyssal Agulhas Fracture Zone, South Atlantic Ocean, and notes on their distributions AV - public EP - 9 ER - TY - RPRT ID - soton50085 UR - https://eprints.soton.ac.uk/50085/ A1 - Williams, A.P. A1 - Hadfield, R.E. Y1 - 2008/01// N2 - This report describes the twelfth repeat hydrography section across Drake Passage, firstDeciphering the evolution of Southern Ocean circulation during the Eocene and Oligocene has important implications for understanding the development of the Antarctic Circumpolar Current and transition to Earth's "icehouse" climate. To better understand ocean circulation patterns in the Indian Ocean sector of the Southern Ocean, we generated a new fossil fish tooth neodymium isotope record (?Nd) from the upper Eocene to upper Oligocene sections (36-23 Ma) of Ocean Drilling Program Sites 744 and 748 (Kerguelen Plateau, Indian Ocean). Reconstructed seawater ?Nd values from fossil fish teeth are used to trace changes in water masses across ocean basins. The records from Site 748 and Site 744 reveal a gradual shift from ?Nd values around -6.5 to -7.5 in the late Eocene to ?Nd values between -7.5 and -8.3 by the late Oligocene, consistent with a Circumpolar Deep Water (CDW) influence at the Kerguelen Plateau throughout the Oligocene. We interpret the shift to less radiogenic values to reflect the increased export of Northern Component Water to the Southern Ocean, likely into the proto-CDW. However, the records show no major change in water mass composition around the Kerguelen Plateau that would accompany an increase in Pacific throughflow related to the opening of Drake Passage and imply that Pacific throughflow via the Drake Passage occurred by the late Eocene. High-frequency variability in eNd values at Site 744 is interpreted as an imprint of Oligocene glacial activity, with a particularly pronounced excursion at 32.6 Ma roughly coinciding with other glacial weathering indicators around Antarctica.
JF - Paleoceanography and Paleoclimatology KW - Eocene-Oligocene transition KW - Kerguelen Plateau KW - Neodymium isotopes KW - Southern Ocean SN - 2572-4525 TI - No change in Southern Ocean circulation in the Indian Ocean from the Eocene through Late Oligocene AV - public ER - TY - RPRT ID - soton71791 UR - https://eprints.soton.ac.uk/71791/ A1 - Yelland, M.J. Y1 - 2009/12// N2 - This report describes the 16th occupation of the Drake Passage CTD section, established duringUnderstanding the boundaries of breeding populations is of great importance for conservation efforts and estimates of extinction risk for threatened species. However, determining these boundaries can be difficult when population structure is subtle. Emperor penguins are highly reliant on sea ice, and some populations may be in jeopardy as climate change alters sea-ice extent and quality. An understanding of emperor penguin population structure is therefore urgently needed. Two previous studies have differed in their conclusions, particularly whether the Ross Sea, a major stronghold for the species, is isolated or not. We assessed emperor penguin population structure using 4,596 genome-wide single nucleotide polymorphisms (SNPs), characterized in 110 individuals (10?16 per colony) from eight colonies around Antarctica. In contrast to a previous conclusion that emperor penguins are panmictic around the entire continent, we find that emperor penguins comprise at least four metapopulations, and that the Ross Sea is clearly a distinct metapopulation. Using larger sample sizes and a thorough assessment of the limitations of different analytical methods, we have shown that population structure within emperor penguins does exist and argue that its recognition is vital for the effective conservation of the species. We discuss the many difficulties that molecular ecologists and managers face in the detection and interpretation of subtle population structure using large SNP data sets, and argue that subtle structure should be taken into account when determining management strategies for threatened species, until accurate estimates of demographic connectivity among populations can be made.
JF - Molecular Ecology VL - 26 KW - Antarctica KW - dispersal KW - population genomics KW - RAD-seq KW - Ross Sea KW - Southern Ocean SN - 0962-1083 TI - The challenges of detecting subtle population structure and its importance for the conservation of emperor penguins SP - 3883 AV - none EP - 3897 ER - TY - JOUR N1 - Funding Information: This study is supported by the National Natural Science Foundation of China Project (No. 91755208, No. 41673043) and the National Key R & D Plan (No. 2017YFC0601404). Publisher Copyright: © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. Copyright: Copyright 2021 Elsevier B.V., All rights reserved. ID - soton453803 UR - https://eprints.soton.ac.uk/453803/ A1 - Zhang, Qiang A1 - Zhao, Kui-dong A1 - Li, Wen-qian A1 - Palmer, Martin R. A1 - Jiang, Shao-yong A1 - Jiang, Hai A1 - Zhang, Wei A1 - Zhang, Di A1 - Hussain, Amjad Y1 - 2021/11/12/ N2 -The southern Myanmar tin ore district is an important part of the well-known Southeast Asia tin belt (SATB), and hosts numerous economically important primary tin-tungsten ore deposits. However, the timing of formation of these deposits is unclear due to the scarcity of robust age data. The tectonic setting of tin mineralization in this area also needs to be further constrained. Most of the primary tin-tungsten ore deposits in southern Myanmar are typical hydrothermal quartz vein?type, with cassiterite and wolframite as the main ore minerals. Here, we present in situ U?Pb ages of cassiterite and wolframite from nine granite-related hydrothermal Sn?W deposits in southern Myanmar. Cassiterite samples from the Hermyingyi, Thitkhatoe, Thaling Taung, Kalonta, Taungphila, Pagaye, Bawapin, Kanbauk, and Letha Taung deposits yield common lead-corrected weighted mean 206Pb/ 238U ages of 61.6 ± 0.8 Ma, 61.9 ± 0.6 Ma, 60.4 ± 0.9 Ma, 63.0 ± 0.6 Ma, 62.9 ± 0.6 Ma, 69.5 ± 0.5 Ma, 63.6 ± 0.6 Ma, 61.3 ± 0.6 Ma, and 84.9 ± 0.5 Ma, respectively. Wolframite samples collected from these deposits also yield consistent ages with the cassiterite samples. These ages, combined with available tin mineralization ages from other deposits in the western part of the SATB, define three epochs of Sn metallogeny related to three contrasting geodynamic settings: (1) Early Cretaceous (~ 125?110 Ma) mineralization is related to post-collision slab break-off after collision between the West Burma terrane and the Sibumasu-Tengchong terrane; (2) Late Cretaceous to Paleocene (~ 90?60 Ma) mineralization developed in an Andean-type accretionary setting during subduction of the Neo-Tethys oceanic lithosphere; (3) Early Eocene (~ 50?40 Ma) mineralization may have formed in a post-collision setting after the India-Asia collision.
JF - Mineralium Deposita KW - Cassiterite KW - Southeast Asia tin belt KW - Southern Myanmar KW - Tin deposits KW - U?Pb geochronology KW - Wolframite SN - 0026-4598 TI - Timing and tectonic setting of tin mineralization in southern Myanmar: constraints from cassiterite and wolframite U?Pb ages AV - public EP - 55 ER - TY - JOUR ID - soton353984 UR - https://eprints.soton.ac.uk/353984/ IS - 5 A1 - Zika, Jan D. A1 - Le Sommer, Julien A1 - Dufour, Carolina O. A1 - Molines, Jean-Marc A1 - Barnier, Bernard A1 - Brasseur, Pierre A1 - Dussin, Raphaël A1 - Penduff, Thierry A1 - Iudicone, Daniele A1 - Lenton, Andrew A1 - Madec, Gurvan A1 - Mathiot, Pierre A1 - Orr, James A1 - Shuckburgh, Emily A1 - Vivier, Frederic Y1 - 2013/05// N2 - The overturning circulation of the Southern Ocean has been investigated using eddying coupled ocean?sea ice models. The circulation is diagnosed in both density?latitude coordinates and in depth?density coordinates. Depth?density coordinates follow streamlines where the Antarctic Circumpolar Current is equivalent barotropic, capture the descent of Antarctic Bottom Water, follow density outcrops at the surface, and can be interpreted energetically. In density?latitude coordinates, wind-driven northward transport of light water and southward transport of dense water are compensated by standing meanders and to a lesser degree by transient eddies, consistent with previous results. In depth?density coordinates, however, wind-driven upwelling of dense water and downwelling of light water are compensated more strongly by transient eddy fluxes than fluxes because of standing meanders. Model realizations are discussed where the wind pattern of the southern annular mode is amplified. In density?latitude coordinates, meridional fluxes because of transient eddies can increase to counter changes in Ekman transport and decrease in response to changes in the standing meanders. In depth?density coordinates, vertical fluxes because of transient eddies directly counter changes in Ekman pumping. JF - Journal of Physical Oceanography VL - 43 KW - Southern Ocean KW - Density currents KW - Eddies KW - Meridional overturning circulation KW - Upwelling/downwelling KW - Coordinate systems SN - 0022-3670 TI - Vertical Eddy Fluxes in the Southern Ocean SP - 941 AV - none EP - 955 ER - TY - JOUR ID - soton337462 UR - https://eprints.soton.ac.uk/337462/ IS - 11 A1 - Zika, Jan D. A1 - Sloyan, Bernadette M. A1 - McDougall, Trevor J. Y1 - 2009/11// N2 - The strength and structure of the Southern Hemisphere meridional overturning circulation (SMOC) is related to the along-isopycnal and vertical mixing coefficients by analyzing tracer and density fields from a hydrographic climatology. The meridional transport of Upper Circumpolar Deep Water (UCDW) across the Antarctic Circumpolar Current (ACC) is expressed in terms of the along-isopycnal (K) and diapycnal (D) tracer diffusivities and in terms of the along-isopycnal potential vorticity mixing coefficient (KPV). Uniform along-isopycnal (<600 m2 s?1) and low vertical mixing (10?5 m2 s?1) can maintain a southward transport of less than 60 Sv (Sv = 106 m2 s?1) of UCDW across the ACC, which is distributed largely across the South Pacific and east Indian Ocean basins. For vertical mixing rates of O(10?4 m2 s?1) or greater, the inferred transport is significantly enhanced. The transports inferred from both tracer and density distributions suggest a ratio K to D of O(2 × 106) particularly on deeper layers of UCDW. Given the range of observed southward transports of UCDW, it is found that K = 300 ± 150 m2 s?1 and D = 10?4 ± 0.5 × 10?4 m2 s?1 in the Southern Ocean interior. A view of the SMOC is revealed where dense waters are converted to lighter waters not only at the ocean surface, but also on depths below that of the mixed layer with vertical mixing playing an important role. JF - Journal of Physical Oceanography VL - 39 KW - Southern Ocean KW - Ocean circulation KW - Meridional Overturning Circulation KW - Tracers KW - Southern Hemisphere SN - 0022-3670 TI - Diagnosing the Southern Ocean Overturning from Tracer Fields SP - 2926 AV - none EP - 2940 ER - TY - JOUR ID - soton49516 UR - https://eprints.soton.ac.uk/49516/ IS - 18-20 A1 - Zubkov, M.V. A1 - Holland, R.J. A1 - Burkill, P.H. A1 - Croudace, I.W. A1 - Warwick, P.E. Y1 - 2007/// N2 - Iron leached from volcanic islands was hypothesised to naturally fertilise the high-nutrient low-chlorophyll (HNLC) waters of the Antarctic Circum Polar Current and to cause recurrent phytoplankton blooms or high-chlorophyll (HC) areas in the wake of the Crozet Islands. As part of CROZEX, the effect of Fe-fertilisation on microbial community was examined by comparing microbial standing stocks and microbial turnover rates of dissolved organic molecules and iron in the HNLC and HC waters in the vicinity of the Crozet Isles. Bacterioplankton and ultraplanktonic algae were enumerated by flow cytometry. Microbial turnover and ambient concentrations of amino acids and glucose in surface waters were bioassayed using an isotopic dilution technique. Microbial uptake of iron was estimated using a carrier-free 55Fe tracer approach. The data set generated did not reveal statistically significant seasonal changes above the observed high spatial variability in the studied area. Statistically significant higher biomass (1.5 times) of heterotrophic bacterioplankton (HB) as well as higher microbial turnover of organic molecules (10 times) were observed in the HC waters relative to the HNLC waters, while relative iron uptake was nearly eight times lower in the HC waters. However, the difference in HB standing stocks in the 100?200 m water layer between the two compared water types was statistically insignificant. Hence, the HC surface waters in austral summer showed higher microbial activity with decreased iron dependency relative to the HNLC waters of the Southern Ocean, in agreement with higher productivity of the waters to the north of the Crozet Islands. JF - Deep Sea Research Part II: Topical Studies in Oceanography VL - 54 KW - Ultraplankton KW - Microbial bioassay KW - Bacterioplankton production KW - Iron tracer uptake KW - Southern Ocean KW - HNLC regions SN - 0967-0645 TI - Microbial abundance, activity and iron uptake in vicinity of the Crozet Isles in November 2004-January 2005 SP - 2126 AV - none EP - 2137 ER - TY - JOUR ID - soton41431 UR - https://eprints.soton.ac.uk/41431/ IS - C9 A1 - de Baar, Hein J.W. A1 - Boyd, Philip W. A1 - Coale, Kenneth H. A1 - Landry, Michael R. A1 - Tsuda, Atsushi A1 - Assmy, Philipp A1 - Bakker, Dorothee C.E. A1 - Bozec, Yann A1 - Barber, Richard T. A1 - Brzezinski, Mark A. A1 - Buesseler, Ken O. A1 - Boye, Marie A1 - Croot, Peter L. A1 - Gervais, Frank A1 - Gorbunov, Maxim Y. A1 - Harrison, Paul J. A1 - Hiscock, William T. A1 - Laan, Patrick A1 - Lancelot, Christiane A1 - Law, Cliff S. A1 - Levasseur, Maurice A1 - Marchetti, Adrian A1 - Millero, Frank J. A1 - Nishioka, Jun A1 - Nojiri, Yukihiro A1 - van Oijen, Tim A1 - Riebesell, Ulf A1 - Rijkenberg, Micha J.A. A1 - Saito, Hiroaki A1 - Takeda, Shigenobu A1 - Timmermans, Klaas R. A1 - Veldhuis, Marcel J.W. A1 - Waite, Anya M. A1 - Wong, Chi-Shing Y1 - 2005/// N2 - Comparison of eight iron experiments shows that maximum Chl a, the maximum DIC removal, and the overall DIC/ Fe efficiency all scale inversely with depth of the wind mixed layer (WML) defining the light environment. Moreover, lateral patch dilution, sea surface irradiance, temperature, and grazing play additional roles. The Southern Ocean experiments were most influenced by very deep WMLs. In contrast, light conditions were most favorable during SEEDS and SERIES as well as during IronEx-2. The two extreme experiments, EisenEx and SEEDS, can be linked via EisenEx bottle incubations with shallower simulated WML depth. Large diatoms always benefit the most from Fe addition, where a remarkably small group of thriving diatom species is dominated by universal response of Pseudo-nitzschia spp. Significant response of these moderate ( 10 - 30 mu m), medium ( 30 - 60 mu m), and large (> 60 mu m) diatoms is consistent with growth physiology determined for single species in natural seawater. The minimum level of "dissolved'' Fe ( filtrate < 0.2 mu m) maintained during an experiment determines the dominant diatom size class. However, this is further complicated by continuous transfer of original truly dissolved reduced Fe(II) into the colloidal pool, which may constitute some 75% of the "dissolved'' pool. Depth integration of carbon inventory changes partly compensates the adverse effects of a deep WML due to its greater integration depths, decreasing the differences in responses between the eight experiments. About half of depth-integrated overall primary productivity is reflected in a decrease of DIC. The overall C/Fe efficiency of DIC uptake is DIC/Fe similar to 5600 for all eight experiments. The increase of particulate organic carbon is about a quarter of the primary production, suggesting food web losses for the other three quarters. Replenishment of DIC by air/sea exchange tends to be a minor few percent of primary CO2 fixation but will continue well after observations have stopped. Export of carbon into deeper waters is difficult to assess and is until now firmly proven and quite modest in only two experiments. JF - Journal of Geophysical Research VL - 110 KW - equatorial Pacific Ocean KW - release experiment soiree KW - sub-Arctic Pacific KW - Austral spring 1992 KW - open Southern Ocean KW - phytoplankton growth KW - enrichment experiment KW - experiment SOFEX KW - sulfur hexafluoride KW - carbon dioxide SN - 0148-0227 TI - Synthesis of iron fertilization experiments: From the Iron Age in the Age of Enlightenment AV - none ER - TY - JOUR ID - soton422422 UR - https://eprints.soton.ac.uk/422422/ A1 - de Souza, Gregory F. A1 - Khatiwala, Samar P. A1 - Hain, Mathis P. A1 - Little, Susan H. A1 - Vance, Derek Y1 - 2018/06/15/ N2 -The close linear correlation between the distributions of dissolved zinc (Zn) and silicon (Si) in seawater has puzzled chemical oceanographers since its discovery almost forty years ago, due to the apparent lack of a mechanism for coupling these two nutrient elements. Recent research has shown that such a correlation can be produced in an ocean model without any explicit coupling between Zn and Si, via the export of Zn-rich biogenic particles in the Southern Ocean, consistent with the observation of elevated Zn quotas in Southern Ocean diatoms. Here, we investigate the physical and biological mechanisms by which Southern Ocean uptake and export control the large-scale marine Zn distribution, using suites of sensitivity simulations in an ocean general circulation model (OGCM) and a box-model ensemble. These simulations focus on the sensitivity of the Zn distribution to the stoichiometry of Zn uptake relative to phosphate (PO4), drawing directly on observations in culture. Our analysis reveals that OGCM model variants that produce a well-defined step between relatively constant, high Zn:PO4 uptake ratios in the Southern Ocean and low Zn:PO4 ratios at lower latitudes fare best in reproducing the marine Zn?Si correlation at both the global and the regional Southern Ocean scale, suggesting the presence of distinct Zn-biogeochemical regimes in the high- and low-latitude oceans that may relate to differences in physiology, ecology or (micro-)nutrient status. Furthermore, a study of the systematics of both the box model and the OGCM reveals that regional Southern Ocean Zn uptake exerts control over the global Zn distribution via its modulation of the biogeochemical characteristics of the surface Southern Ocean. Specifically, model variants with elevated Southern Ocean Zn:PO4 uptake ratios produce near-complete Zn depletion in the Si-poor surface Subantarctic Zone, where upper-ocean water masses with key roles in the global oceanic circulation are formed. By setting the main preformed covariation trend within the ocean interior, the subduction of these Zn- and Si-poor water masses produces a close correlation between the Zn and Si distributions that is barely altered by their differential remineralisation during low-latitude cycling. We speculate that analogous processes in the high-latitude oceans may operate for other trace metal micronutrients as well, splitting the ocean into two fundamentally different biogeochemical, and thus biogeographic, regimes.
JF - Earth and Planetary Science Letters VL - 492 KW - diatoms KW - GEOTRACES KW - ocean biogeochemistry KW - Southern Ocean SN - 0012-821X TI - On the origin of the marine zinc?silicon correlation SP - 22 AV - none EP - 34 ER - TY - JOUR ID - soton385962 UR - https://eprints.soton.ac.uk/385962/ IS - 3 A1 - van Bellen, S. A1 - Mauquoy, D. A1 - Hughes, P. A1 - Roland, T.P. A1 - Daley, T.J. A1 - Loader, N.J. A1 - Street-Perrott, F.A. A1 - Rice, E.M. A1 - Pancotto, V.A. A1 - Payne, R.J. Y1 - 2016/03/01/ N2 - The ombrotrophic peat bogs of Tierra del Fuego are located within the southern westerly wind belt (SWWB), which dominates climate variability in this region. We have reconstructed late-Holocene water-table depths from three peat bogs and aimed to relate these records to shifts in regional climate. Water-table depths were quantified by the analysis of testate amoeba assemblages, and a regional transfer function was used to infer past water-table depths. During the last 2000?years, testate amoeba assemblages have been relatively stable, with a dominance of Difflugia pulex and Difflugia pristis type, and an increase in Assulina muscorum and other Euglyphida at the top of each section. Multivariate analyses show that water-table depth remained the main environmental variable explaining assemblages along the TiA12 core, but reconstructions were not significant for the two other cores. In line with the low variability in assemblages, water tables were relatively stable during the last 2000?years. Slightly wetter conditions were found between ~1400 and 900 cal. BP and a pronounced recent dry shift was reconstructed in all of the three peat profiles. Considering the regional climatic context, this recent shift may have been forced by a decrease in precipitation and warmer conditions linked to an increase in the importance of the SWWB. Nevertheless, we cannot exclude the influence of higher UV-B radiation resulting from the local degradation of the ozone layer since the late 1970s, which may have had an additional effect on the relative presence of A. muscorum in the southern Patagonian region. JF - The Holocene VL - 26 KW - assulina muscorum KW - palaeoSig KW - patagonia KW - southern annular mode KW - southern westerly wind KW - uv-B SN - 0959-6836 TI - Late-Holocene climate dynamics recorded in the peat bogs of Tierra del Fuego, South America SP - 489 AV - public EP - 501 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 -