Barnett, Michelle, Kemp, Alan, Hickman, Anna and Purdie, Duncan (2019) Shelf sea subsurface chlorophyll maximum thin layers have a distinct phytoplankton community structure. Continental Shelf Research, 174, 140-157. (doi:10.1016/j.csr.2018.12.007).
Abstract
The Western English Channel is a seasonally stratified temperate coastal sea where a subsurface chlorophyll maximum (SCM) is typically detectable within the seasonal thermocline. The SCM often develops as a thin layer(<5m) that may contain elevated concentrations of phytoplankton (subsurface chlorophyll maximum thin layer;SCMTL). During summer 2013 a study was conducted offshore of Falmouth, UK to assess spatial and short-termtemporal variability in SCM thickness in relation to water column structure and physical conditions and to evaluateany associated changes in phytoplankton community structure. SCMTL were observed in 18 of 52 verticalprofiles, typically characterised by higher chlorophyll concentrations than broader SCM. SCMTL were generallyassociated with a ‘stepped’ thermocline, likely representing the presence of one or more shallow mixed layersforming above/within the seasonal thermocline, and related to increased stratification and stability compared tobroader SCM. Pseudo-nitzschia was almost exclusively the dominant diatom taxon in SCM, yet statistically distinctdifferences in community structure existed between SCMTL and broader SCM. Within the phytoplankton,the distinction was largely due to a greater biomass of Proboscia alata and other rhizosolenid diatoms, and thedinoflagellate Ceratium lineatum in SCMTL, and a smaller population of the diatom Chaetoceros spp. There wasalso a distinction amongst heterotrophic dinoflagellates, with enhanced biomass of Gyrodinium spp. in SCMTLand a reduction in Diplopsalis lenticula. We propose that this observed difference resulted from promotion of phytoplanktonbetter adapted to environmental conditions more specific to SCMTL compared to broader SCM. Withmore intense and prolonged stratification projected for the NW European shelf, there may be increased prevalenceof SCMTL and the associated larger-sized specialised taxa, with implications for increased carbon export.This study adds to a growing body of evidence of the importance of SCMTL in coastal and shelf seas, and highlightsthe requirement for improved understanding of physical forcing, and the ecology and physiology of keytaxa, particularly as predicted changes in stratification could alter the role of SCM phytoplankton in a future influencedby climate change
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- Current Faculties > Faculty of Environmental and Life Sciences > School of Ocean and Earth Science > Marine Biogeochemistry
School of Ocean and Earth Science > Marine Biogeochemistry - Faculties (pre 2018 reorg) > Faculty of Engineering and the Environment (pre 2018 reorg) > Southampton Marine & Maritime Institute (pre 2018 reorg)
- Current Faculties > Faculty of Environmental and Life Sciences > School of Ocean and Earth Science
School of Ocean and Earth Science - Faculties (pre 2018 reorg) > Faculty of Natural and Environmental Sciences (pre 2018 reorg) > Institute for Life Sciences (pre 2018 reorg)
Current Faculties > Faculty of Environmental and Life Sciences > Institute for Life Sciences > Institute for Life Sciences (pre 2018 reorg)
Institute for Life Sciences > Institute for Life Sciences (pre 2018 reorg) - Faculties (pre 2018 reorg) > Faculty of Natural and Environmental Sciences (pre 2018 reorg) > Ocean and Earth Science (pre 2018 reorg)
Current Faculties > Faculty of Environmental and Life Sciences > School of Ocean and Earth Science > Ocean and Earth Science (pre 2018 reorg)
School of Ocean and Earth Science > Ocean and Earth Science (pre 2018 reorg) - Current Faculties > Faculty of Environmental and Life Sciences > School of Ocean and Earth Science > Paleooceanography and Palaeoclimate
School of Ocean and Earth Science > Paleooceanography and Palaeoclimate - Faculties (pre 2011 reorg) > Faculty of Engineering Science & Maths (pre 2011 reorg) > Ocean and Earth Science (pre 2011 reorg)
Current Faculties > Faculty of Environmental and Life Sciences > School of Ocean and Earth Science > Ocean and Earth Science (pre 2011 reorg)
School of Ocean and Earth Science > Ocean and Earth Science (pre 2011 reorg)
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