Factors influencing the stable carbon isotopic composition of suspended and sinking organic matter in the coastal Antarctic sea ice environment
A high resolution time-series analysis of stable carbon isotopic signatures in particulate organic carbon (δ 13 C POC ) and associated biogeochemical parameters in sea ice and surface waters provides an insight into the factors affecting δ 13 C POC in the coastal western Antarctic Peninsula sea ice...
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ftcopernicus:oai:publications.copernicus.org:bg13027 2023-05-15T13:45:55+02:00 Factors influencing the stable carbon isotopic composition of suspended and sinking organic matter in the coastal Antarctic sea ice environment Henley, S. F. Annett, A. L. Ganeshram, R. S. Carson, D. S. Weston, K. Crosta, X. Tait, A. Dougans, J. Fallick, A. E. Clarke, A. 2018-09-27 application/pdf https://doi.org/10.5194/bg-9-1137-2012 https://www.biogeosciences.net/9/1137/2012/ eng eng doi:10.5194/bg-9-1137-2012 https://www.biogeosciences.net/9/1137/2012/ eISSN: 1726-4189 Text 2018 ftcopernicus https://doi.org/10.5194/bg-9-1137-2012 2019-12-24T09:56:21Z A high resolution time-series analysis of stable carbon isotopic signatures in particulate organic carbon (δ 13 C POC ) and associated biogeochemical parameters in sea ice and surface waters provides an insight into the factors affecting δ 13 C POC in the coastal western Antarctic Peninsula sea ice environment. The study covers two austral summer seasons in Ryder Bay, northern Marguerite Bay between 2004 and 2006. A shift in diatom species composition during the 2005/06 summer bloom to near-complete biomass dominance of Proboscia inermis is strongly correlated with a large ~10 ‰ negative isotopic shift in δ 13 C POC that cannot be explained by a concurrent change in concentration or isotopic signature of CO 2 . We hypothesise that the δ 13 C POC shift may be driven by the contrasting biochemical mechanisms and utilisation of carbon-concentrating mechanisms (CCMs) in different diatom species. Specifically, very low δ 13 C POC in P. inermis may be caused by the lack of a CCM, whilst some diatom species abundant at times of higher δ 13 C POC may employ CCMs. These short-lived yet pronounced negative δ 13 C POC excursions drive a 4 ‰ decrease in the seasonal average δ 13 C POC signal, which is transferred to sediment traps and core-top sediments and consequently has the potential for preservation in the sedimentary record. This 4 ‰ difference between seasons of contrasting sea ice conditions and upper water column stratification matches the full amplitude of glacial-interglacial Southern Ocean δ 13 C POC variability and, as such, we invoke phytoplankton species changes as a potentially important factor influencing sedimentary δ 13 C POC . We also find significantly higher δ 13 C POC in sea ice than surface waters, consistent with autotrophic carbon fixation in a semi-closed environment and possible contributions from post-production degradation, biological utilisation of HCO 3 − and production of exopolymeric substances. This study demonstrates the importance of surface water diatom speciation effects and isotopically heavy sea ice-derived material for δ 13 C POC in Antarctic coastal environments and underlying sediments, with consequences for the utility of diatom-based δ 13 C POC in the sedimentary record. Text Antarc* Antarctic Antarctic Peninsula Sea ice Southern Ocean Copernicus Publications: E-Journals Antarctic Antarctic Peninsula Austral Marguerite ENVELOPE(141.378,141.378,-66.787,-66.787) Marguerite Bay ENVELOPE(-68.000,-68.000,-68.500,-68.500) Ryder ENVELOPE(-68.333,-68.333,-67.566,-67.566) Ryder Bay ENVELOPE(-68.333,-68.333,-67.567,-67.567) Southern Ocean Biogeosciences 9 3 1137 1157 |
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Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
A high resolution time-series analysis of stable carbon isotopic signatures in particulate organic carbon (δ 13 C POC ) and associated biogeochemical parameters in sea ice and surface waters provides an insight into the factors affecting δ 13 C POC in the coastal western Antarctic Peninsula sea ice environment. The study covers two austral summer seasons in Ryder Bay, northern Marguerite Bay between 2004 and 2006. A shift in diatom species composition during the 2005/06 summer bloom to near-complete biomass dominance of Proboscia inermis is strongly correlated with a large ~10 ‰ negative isotopic shift in δ 13 C POC that cannot be explained by a concurrent change in concentration or isotopic signature of CO 2 . We hypothesise that the δ 13 C POC shift may be driven by the contrasting biochemical mechanisms and utilisation of carbon-concentrating mechanisms (CCMs) in different diatom species. Specifically, very low δ 13 C POC in P. inermis may be caused by the lack of a CCM, whilst some diatom species abundant at times of higher δ 13 C POC may employ CCMs. These short-lived yet pronounced negative δ 13 C POC excursions drive a 4 ‰ decrease in the seasonal average δ 13 C POC signal, which is transferred to sediment traps and core-top sediments and consequently has the potential for preservation in the sedimentary record. This 4 ‰ difference between seasons of contrasting sea ice conditions and upper water column stratification matches the full amplitude of glacial-interglacial Southern Ocean δ 13 C POC variability and, as such, we invoke phytoplankton species changes as a potentially important factor influencing sedimentary δ 13 C POC . We also find significantly higher δ 13 C POC in sea ice than surface waters, consistent with autotrophic carbon fixation in a semi-closed environment and possible contributions from post-production degradation, biological utilisation of HCO 3 − and production of exopolymeric substances. This study demonstrates the importance of surface water diatom speciation effects and isotopically heavy sea ice-derived material for δ 13 C POC in Antarctic coastal environments and underlying sediments, with consequences for the utility of diatom-based δ 13 C POC in the sedimentary record. |
format |
Text |
author |
Henley, S. F. Annett, A. L. Ganeshram, R. S. Carson, D. S. Weston, K. Crosta, X. Tait, A. Dougans, J. Fallick, A. E. Clarke, A. |
spellingShingle |
Henley, S. F. Annett, A. L. Ganeshram, R. S. Carson, D. S. Weston, K. Crosta, X. Tait, A. Dougans, J. Fallick, A. E. Clarke, A. Factors influencing the stable carbon isotopic composition of suspended and sinking organic matter in the coastal Antarctic sea ice environment |
author_facet |
Henley, S. F. Annett, A. L. Ganeshram, R. S. Carson, D. S. Weston, K. Crosta, X. Tait, A. Dougans, J. Fallick, A. E. Clarke, A. |
author_sort |
Henley, S. F. |
title |
Factors influencing the stable carbon isotopic composition of suspended and sinking organic matter in the coastal Antarctic sea ice environment |
title_short |
Factors influencing the stable carbon isotopic composition of suspended and sinking organic matter in the coastal Antarctic sea ice environment |
title_full |
Factors influencing the stable carbon isotopic composition of suspended and sinking organic matter in the coastal Antarctic sea ice environment |
title_fullStr |
Factors influencing the stable carbon isotopic composition of suspended and sinking organic matter in the coastal Antarctic sea ice environment |
title_full_unstemmed |
Factors influencing the stable carbon isotopic composition of suspended and sinking organic matter in the coastal Antarctic sea ice environment |
title_sort |
factors influencing the stable carbon isotopic composition of suspended and sinking organic matter in the coastal antarctic sea ice environment |
publishDate |
2018 |
url |
https://doi.org/10.5194/bg-9-1137-2012 https://www.biogeosciences.net/9/1137/2012/ |
long_lat |
ENVELOPE(141.378,141.378,-66.787,-66.787) ENVELOPE(-68.000,-68.000,-68.500,-68.500) ENVELOPE(-68.333,-68.333,-67.566,-67.566) ENVELOPE(-68.333,-68.333,-67.567,-67.567) |
geographic |
Antarctic Antarctic Peninsula Austral Marguerite Marguerite Bay Ryder Ryder Bay Southern Ocean |
geographic_facet |
Antarctic Antarctic Peninsula Austral Marguerite Marguerite Bay Ryder Ryder Bay Southern Ocean |
genre |
Antarc* Antarctic Antarctic Peninsula Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Sea ice Southern Ocean |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-9-1137-2012 https://www.biogeosciences.net/9/1137/2012/ |
op_doi |
https://doi.org/10.5194/bg-9-1137-2012 |
container_title |
Biogeosciences |
container_volume |
9 |
container_issue |
3 |
container_start_page |
1137 |
op_container_end_page |
1157 |
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1766232500975173632 |