Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean:a stable isotope approach
The biological carbon pump is responsible for much of the decadal variability in the ocean carbon dioxide (CO2) sink, driving the transfer of carbon from the atmosphere to the deep ocean. A mechanistic understanding of the ecological drivers of particulate organic carbon (POC) flux is key both to th...
Published in: | Biogeosciences |
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2023
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Online Access: | https://hdl.handle.net/1983/545d30dd-a5ab-4d53-9be5-6373cf9edc65 https://research-information.bris.ac.uk/en/publications/545d30dd-a5ab-4d53-9be5-6373cf9edc65 https://doi.org/10.5194/bg-20-3573-2023 https://bg.copernicus.org/articles/20/3573/2023/ |
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ftubristolcris:oai:research-information.bris.ac.uk:publications/545d30dd-a5ab-4d53-9be5-6373cf9edc65 2024-01-07T09:46:36+01:00 Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean:a stable isotope approach Belcher, Anna Henley, Sian f. Hendry, Katharine Wootton, Marianne Friberg, Lisa Dallman, Ursula Wang, Tong Coath, Christopher Manno, Clara 2023-08-25 https://hdl.handle.net/1983/545d30dd-a5ab-4d53-9be5-6373cf9edc65 https://research-information.bris.ac.uk/en/publications/545d30dd-a5ab-4d53-9be5-6373cf9edc65 https://doi.org/10.5194/bg-20-3573-2023 https://bg.copernicus.org/articles/20/3573/2023/ eng eng info:eu-repo/semantics/openAccess Belcher , A , Henley , S F , Hendry , K , Wootton , M , Friberg , L , Dallman , U , Wang , T , Coath , C & Manno , C 2023 , ' Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean : a stable isotope approach ' , Biogeosciences , vol. 20 , no. 16 , pp. 3573-3591 . https://doi.org/10.5194/bg-20-3573-2023 article 2023 ftubristolcris https://doi.org/10.5194/bg-20-3573-2023 2023-12-14T23:34:39Z The biological carbon pump is responsible for much of the decadal variability in the ocean carbon dioxide (CO2) sink, driving the transfer of carbon from the atmosphere to the deep ocean. A mechanistic understanding of the ecological drivers of particulate organic carbon (POC) flux is key both to the assessment of the magnitude of the ocean CO2 sink and for accurate predictions as to how this will change with changing climate. This is particularly important in the Southern Ocean, a key region for the uptake of CO2 and the supply of nutrients to the global thermocline. In this study we examine sediment-trap-derived particle fluxes and stable isotope signatures of carbon (C), nitrogen (N), and biogenic silica (BSi) at a study site in the biologically productive waters of the northern Scotia Sea in the Southern Ocean. Both deep (2000 m) and shallow (400 m) sediment traps exhibited two main peaks in POC, particulate N, and BSi flux: one in austral spring and one in summer, reflecting periods of high surface productivity. Particulate fluxes and isotopic compositions were similar in both deep and shallow sediment traps, highlighting that most remineralisation occurred in the upper 400 m of the water column. Differences in the seasonal cycles of isotopic compositions of C, N, and Si provide insights into the degree of coupling of these key nutrients. We measured increasing isotopic enrichment of POC and BSi in spring, consistent with fractionation during biological uptake. Since we observed isotopically light particulate material in the traps in summer, we suggest physically mediated replenishment of lighter isotopes of key nutrients from depth, enabling the full expression of the isotopic fractionation associated with biological uptake. The change in the nutrient and remineralisation regimes, indicated by the different isotopic compositions of the spring and summer productive periods, suggests a change in the source region of material reaching the traps and associated shifts in phytoplankton community structure. This, ... Article in Journal/Newspaper Scotia Sea Southern Ocean University of Bristol: Bristol Research Austral Scotia Sea Southern Ocean Biogeosciences 20 16 3573 3591 |
institution |
Open Polar |
collection |
University of Bristol: Bristol Research |
op_collection_id |
ftubristolcris |
language |
English |
description |
The biological carbon pump is responsible for much of the decadal variability in the ocean carbon dioxide (CO2) sink, driving the transfer of carbon from the atmosphere to the deep ocean. A mechanistic understanding of the ecological drivers of particulate organic carbon (POC) flux is key both to the assessment of the magnitude of the ocean CO2 sink and for accurate predictions as to how this will change with changing climate. This is particularly important in the Southern Ocean, a key region for the uptake of CO2 and the supply of nutrients to the global thermocline. In this study we examine sediment-trap-derived particle fluxes and stable isotope signatures of carbon (C), nitrogen (N), and biogenic silica (BSi) at a study site in the biologically productive waters of the northern Scotia Sea in the Southern Ocean. Both deep (2000 m) and shallow (400 m) sediment traps exhibited two main peaks in POC, particulate N, and BSi flux: one in austral spring and one in summer, reflecting periods of high surface productivity. Particulate fluxes and isotopic compositions were similar in both deep and shallow sediment traps, highlighting that most remineralisation occurred in the upper 400 m of the water column. Differences in the seasonal cycles of isotopic compositions of C, N, and Si provide insights into the degree of coupling of these key nutrients. We measured increasing isotopic enrichment of POC and BSi in spring, consistent with fractionation during biological uptake. Since we observed isotopically light particulate material in the traps in summer, we suggest physically mediated replenishment of lighter isotopes of key nutrients from depth, enabling the full expression of the isotopic fractionation associated with biological uptake. The change in the nutrient and remineralisation regimes, indicated by the different isotopic compositions of the spring and summer productive periods, suggests a change in the source region of material reaching the traps and associated shifts in phytoplankton community structure. This, ... |
format |
Article in Journal/Newspaper |
author |
Belcher, Anna Henley, Sian f. Hendry, Katharine Wootton, Marianne Friberg, Lisa Dallman, Ursula Wang, Tong Coath, Christopher Manno, Clara |
spellingShingle |
Belcher, Anna Henley, Sian f. Hendry, Katharine Wootton, Marianne Friberg, Lisa Dallman, Ursula Wang, Tong Coath, Christopher Manno, Clara Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean:a stable isotope approach |
author_facet |
Belcher, Anna Henley, Sian f. Hendry, Katharine Wootton, Marianne Friberg, Lisa Dallman, Ursula Wang, Tong Coath, Christopher Manno, Clara |
author_sort |
Belcher, Anna |
title |
Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean:a stable isotope approach |
title_short |
Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean:a stable isotope approach |
title_full |
Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean:a stable isotope approach |
title_fullStr |
Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean:a stable isotope approach |
title_full_unstemmed |
Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean:a stable isotope approach |
title_sort |
seasonal cycles of biogeochemical fluxes in the scotia sea, southern ocean:a stable isotope approach |
publishDate |
2023 |
url |
https://hdl.handle.net/1983/545d30dd-a5ab-4d53-9be5-6373cf9edc65 https://research-information.bris.ac.uk/en/publications/545d30dd-a5ab-4d53-9be5-6373cf9edc65 https://doi.org/10.5194/bg-20-3573-2023 https://bg.copernicus.org/articles/20/3573/2023/ |
geographic |
Austral Scotia Sea Southern Ocean |
geographic_facet |
Austral Scotia Sea Southern Ocean |
genre |
Scotia Sea Southern Ocean |
genre_facet |
Scotia Sea Southern Ocean |
op_source |
Belcher , A , Henley , S F , Hendry , K , Wootton , M , Friberg , L , Dallman , U , Wang , T , Coath , C & Manno , C 2023 , ' Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean : a stable isotope approach ' , Biogeosciences , vol. 20 , no. 16 , pp. 3573-3591 . https://doi.org/10.5194/bg-20-3573-2023 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/bg-20-3573-2023 |
container_title |
Biogeosciences |
container_volume |
20 |
container_issue |
16 |
container_start_page |
3573 |
op_container_end_page |
3591 |
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1787428452912070656 |