Biological production in the Bellingshausen Sea from oxygen-to-argon ratios and oxygen triple isotopes
We present estimates of mixed-layer net community oxygen production (N) and gross oxygen production (G) of the Bellingshausen Sea in March and April 2007. N was derived from oxygen-to-argon (O2/Ar) ratios; G was derived using the dual-delta method from triple oxygen isotope measurements. In addition...
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Copernicus Publications on behalf of the European Geosciences Union
2013
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Online Access: | http://nora.nerc.ac.uk/id/eprint/501262/ https://nora.nerc.ac.uk/id/eprint/501262/1/bg-10-2273-2013.pdf https://doi.org/10.5194/bg-10-2273-2013 |
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ftnerc:oai:nora.nerc.ac.uk:501262 2023-05-15T15:41:23+02:00 Biological production in the Bellingshausen Sea from oxygen-to-argon ratios and oxygen triple isotopes Castro-Morales, K. Cassar, N. Shoosmith, D.R. Kaiser, J. 2013-04-05 text http://nora.nerc.ac.uk/id/eprint/501262/ https://nora.nerc.ac.uk/id/eprint/501262/1/bg-10-2273-2013.pdf https://doi.org/10.5194/bg-10-2273-2013 en eng Copernicus Publications on behalf of the European Geosciences Union https://nora.nerc.ac.uk/id/eprint/501262/1/bg-10-2273-2013.pdf Castro-Morales, K.; Cassar, N.; Shoosmith, D.R.; Kaiser, J. 2013 Biological production in the Bellingshausen Sea from oxygen-to-argon ratios and oxygen triple isotopes. Biogeosciences, 10 (4). 2273-2291. https://doi.org/10.5194/bg-10-2273-2013 <https://doi.org/10.5194/bg-10-2273-2013> Publication - Article PeerReviewed 2013 ftnerc https://doi.org/10.5194/bg-10-2273-2013 2023-02-04T19:36:40Z We present estimates of mixed-layer net community oxygen production (N) and gross oxygen production (G) of the Bellingshausen Sea in March and April 2007. N was derived from oxygen-to-argon (O2/Ar) ratios; G was derived using the dual-delta method from triple oxygen isotope measurements. In addition, O2 profiles were collected at 253 CTD stations. N is often approximated by the biological oxygen air–sea exchange flux (Fbio based on the O2/Ar supersaturation, assuming that significant horizontal or vertical fluxes are absent. Here we show that the effect of vertical fluxes alone can account for Fbio values < 0 in large parts of the Bellingshausen Sea towards the end of the productive season, which could otherwise be mistaken to represent net heterotrophy. Thus, improved estimates of mixed-layer N can be derived from the sum of Fbio, Fe (entrainment from the upper thermocline during mixed-layer deepening) and Fv (diapycnal eddy diffusion across the base of the mixed layer). In the winter sea ice zone (WSIZ), the corresponding correction results in a small change of Fbio = (30 ± 17) mmol m−2 d−1 to N = (34 ± 17) mmol m−2 d−1. However, in the permanent open ocean zone (POOZ), the original Fbio value of (−17 ± 10) mmol m−2 d−1 gives a corrected value for N of (−2 ± 18) mmol m−2 d−1. We hypothesize that in the WSIZ, enhanced water column stability due to the release of freshwater and nutrients from sea ice melt may account for the higher N value. These results stress the importance of accounting for physical biases when estimating mixed-layer marine productivity from in situ O2/Ar ratios. Article in Journal/Newspaper Bellingshausen Sea Sea ice Natural Environment Research Council: NERC Open Research Archive Bellingshausen Sea Biogeosciences 10 4 2273 2291 |
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Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
We present estimates of mixed-layer net community oxygen production (N) and gross oxygen production (G) of the Bellingshausen Sea in March and April 2007. N was derived from oxygen-to-argon (O2/Ar) ratios; G was derived using the dual-delta method from triple oxygen isotope measurements. In addition, O2 profiles were collected at 253 CTD stations. N is often approximated by the biological oxygen air–sea exchange flux (Fbio based on the O2/Ar supersaturation, assuming that significant horizontal or vertical fluxes are absent. Here we show that the effect of vertical fluxes alone can account for Fbio values < 0 in large parts of the Bellingshausen Sea towards the end of the productive season, which could otherwise be mistaken to represent net heterotrophy. Thus, improved estimates of mixed-layer N can be derived from the sum of Fbio, Fe (entrainment from the upper thermocline during mixed-layer deepening) and Fv (diapycnal eddy diffusion across the base of the mixed layer). In the winter sea ice zone (WSIZ), the corresponding correction results in a small change of Fbio = (30 ± 17) mmol m−2 d−1 to N = (34 ± 17) mmol m−2 d−1. However, in the permanent open ocean zone (POOZ), the original Fbio value of (−17 ± 10) mmol m−2 d−1 gives a corrected value for N of (−2 ± 18) mmol m−2 d−1. We hypothesize that in the WSIZ, enhanced water column stability due to the release of freshwater and nutrients from sea ice melt may account for the higher N value. These results stress the importance of accounting for physical biases when estimating mixed-layer marine productivity from in situ O2/Ar ratios. |
format |
Article in Journal/Newspaper |
author |
Castro-Morales, K. Cassar, N. Shoosmith, D.R. Kaiser, J. |
spellingShingle |
Castro-Morales, K. Cassar, N. Shoosmith, D.R. Kaiser, J. Biological production in the Bellingshausen Sea from oxygen-to-argon ratios and oxygen triple isotopes |
author_facet |
Castro-Morales, K. Cassar, N. Shoosmith, D.R. Kaiser, J. |
author_sort |
Castro-Morales, K. |
title |
Biological production in the Bellingshausen Sea from oxygen-to-argon ratios and oxygen triple isotopes |
title_short |
Biological production in the Bellingshausen Sea from oxygen-to-argon ratios and oxygen triple isotopes |
title_full |
Biological production in the Bellingshausen Sea from oxygen-to-argon ratios and oxygen triple isotopes |
title_fullStr |
Biological production in the Bellingshausen Sea from oxygen-to-argon ratios and oxygen triple isotopes |
title_full_unstemmed |
Biological production in the Bellingshausen Sea from oxygen-to-argon ratios and oxygen triple isotopes |
title_sort |
biological production in the bellingshausen sea from oxygen-to-argon ratios and oxygen triple isotopes |
publisher |
Copernicus Publications on behalf of the European Geosciences Union |
publishDate |
2013 |
url |
http://nora.nerc.ac.uk/id/eprint/501262/ https://nora.nerc.ac.uk/id/eprint/501262/1/bg-10-2273-2013.pdf https://doi.org/10.5194/bg-10-2273-2013 |
geographic |
Bellingshausen Sea |
geographic_facet |
Bellingshausen Sea |
genre |
Bellingshausen Sea Sea ice |
genre_facet |
Bellingshausen Sea Sea ice |
op_relation |
https://nora.nerc.ac.uk/id/eprint/501262/1/bg-10-2273-2013.pdf Castro-Morales, K.; Cassar, N.; Shoosmith, D.R.; Kaiser, J. 2013 Biological production in the Bellingshausen Sea from oxygen-to-argon ratios and oxygen triple isotopes. Biogeosciences, 10 (4). 2273-2291. https://doi.org/10.5194/bg-10-2273-2013 <https://doi.org/10.5194/bg-10-2273-2013> |
op_doi |
https://doi.org/10.5194/bg-10-2273-2013 |
container_title |
Biogeosciences |
container_volume |
10 |
container_issue |
4 |
container_start_page |
2273 |
op_container_end_page |
2291 |
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1766374279045185536 |