Nitrogen uptake by phytoplankton in the Atlantic sector of the Southern Ocean during late austral summer
International audience As part of the Bonus-GoodHope (BGH) campaign, 15N-labelled nitrate, ammonium and urea uptake measurements were made along the BGH transect from Cape Town to ~60° S in late austral summer, 2008. Our results are categorised according to distinct hydrographic regions defined by o...
Published in: | Biogeosciences |
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Main Authors: | , , , , , , , |
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Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2011
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Online Access: | https://hal.science/hal-00641423 https://hal.science/hal-00641423/document https://hal.science/hal-00641423/file/bg-Joubert-8-2947-2011.pdf https://doi.org/10.5194/bg-8-2947-2011 |
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Open Polar |
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Institut national des sciences de l'Univers: HAL-INSU |
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ftinsu |
language |
English |
topic |
[SDE]Environmental Sciences |
spellingShingle |
[SDE]Environmental Sciences Joubert, W.R. Thomalla, S.J. Waldron, H.N. Lucas, M.I. Boye, Marie Le Moigne, F.A Planchon, Frédéric Speich, Sabrina Nitrogen uptake by phytoplankton in the Atlantic sector of the Southern Ocean during late austral summer |
topic_facet |
[SDE]Environmental Sciences |
description |
International audience As part of the Bonus-GoodHope (BGH) campaign, 15N-labelled nitrate, ammonium and urea uptake measurements were made along the BGH transect from Cape Town to ~60° S in late austral summer, 2008. Our results are categorised according to distinct hydrographic regions defined by oceanic fronts and open ocean zones. High regenerated nitrate uptake rate in the oligotrophic Subtropical Zone (STZ) resulted in low f-ratios (f = 0.2) with nitrogen uptake being dominated by ρurea, which contributed up to 70 % of total nitrogen uptake. Size fractionated chlorophyll data showed that the greatest contribution (>50 %) of picophytoplankton (<2 μm) were found in the STZ, consistent with a community based on regenerated production. The Subantarctic Zone (SAZ) showed the greatest total integrated nitrogen uptake (10.3 mmol m−2 d−1), mainly due to enhanced nutrient supply within an anticyclonic eddy observed in this region. A decrease in the contribution of smaller size classes to the phytoplankton community was observed with increasing latitude, concurrent with a decrease in the contribution of regenerated production. Higher f-ratios observed in the SAZ (f = 0.49), Polar Frontal Zone (f= 0.41) and Antarctic Zone (f = 0.45) relative to the STZ (f = 0.24), indicate a higher contribution of NO3−-uptake relative to total nitrogen and potentially higher export production. High ambient regenerated nutrient concentrations are indicative of active regeneration processes throughout the transect and ascribed to late summer season sampling. Higher depth integrated uptake rates also correspond with higher surface iron concentrations. No clear correlation was observed between carbon export estimates derived from new production and 234Th flux. In addition, export derived from 15N estimates were 2-20 times greater than those based on 234Th flux. Variability in the magnitude of export is likely due to intrinsically different methods, compounded by differences in integration time scales for the two proxies of carbon ... |
author2 |
Council for Scientific and Industrial Research Department of Oceanography Cape Town University of Cape Town Department of Zoology Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Laboratoire de physique des océans (LPO) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Joubert, W.R. Thomalla, S.J. Waldron, H.N. Lucas, M.I. Boye, Marie Le Moigne, F.A Planchon, Frédéric Speich, Sabrina |
author_facet |
Joubert, W.R. Thomalla, S.J. Waldron, H.N. Lucas, M.I. Boye, Marie Le Moigne, F.A Planchon, Frédéric Speich, Sabrina |
author_sort |
Joubert, W.R. |
title |
Nitrogen uptake by phytoplankton in the Atlantic sector of the Southern Ocean during late austral summer |
title_short |
Nitrogen uptake by phytoplankton in the Atlantic sector of the Southern Ocean during late austral summer |
title_full |
Nitrogen uptake by phytoplankton in the Atlantic sector of the Southern Ocean during late austral summer |
title_fullStr |
Nitrogen uptake by phytoplankton in the Atlantic sector of the Southern Ocean during late austral summer |
title_full_unstemmed |
Nitrogen uptake by phytoplankton in the Atlantic sector of the Southern Ocean during late austral summer |
title_sort |
nitrogen uptake by phytoplankton in the atlantic sector of the southern ocean during late austral summer |
publisher |
HAL CCSD |
publishDate |
2011 |
url |
https://hal.science/hal-00641423 https://hal.science/hal-00641423/document https://hal.science/hal-00641423/file/bg-Joubert-8-2947-2011.pdf https://doi.org/10.5194/bg-8-2947-2011 |
geographic |
Antarctic Austral Southern Ocean |
geographic_facet |
Antarctic Austral Southern Ocean |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.science/hal-00641423 Biogeosciences, 2011, 85, pp.2947-2959. ⟨10.5194/bg-8-2947-2011⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-8-2947-2011 hal-00641423 https://hal.science/hal-00641423 https://hal.science/hal-00641423/document https://hal.science/hal-00641423/file/bg-Joubert-8-2947-2011.pdf doi:10.5194/bg-8-2947-2011 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.5194/bg-8-2947-2011 |
container_title |
Biogeosciences |
container_volume |
8 |
container_issue |
10 |
container_start_page |
2947 |
op_container_end_page |
2959 |
_version_ |
1790602972392062976 |
spelling |
ftinsu:oai:HAL:hal-00641423v1 2024-02-11T09:56:25+01:00 Nitrogen uptake by phytoplankton in the Atlantic sector of the Southern Ocean during late austral summer Joubert, W.R. Thomalla, S.J. Waldron, H.N. Lucas, M.I. Boye, Marie Le Moigne, F.A Planchon, Frédéric Speich, Sabrina Council for Scientific and Industrial Research Department of Oceanography Cape Town University of Cape Town Department of Zoology Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Laboratoire de physique des océans (LPO) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) 2011-10-21 https://hal.science/hal-00641423 https://hal.science/hal-00641423/document https://hal.science/hal-00641423/file/bg-Joubert-8-2947-2011.pdf https://doi.org/10.5194/bg-8-2947-2011 en eng HAL CCSD European Geosciences Union info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-8-2947-2011 hal-00641423 https://hal.science/hal-00641423 https://hal.science/hal-00641423/document https://hal.science/hal-00641423/file/bg-Joubert-8-2947-2011.pdf doi:10.5194/bg-8-2947-2011 info:eu-repo/semantics/OpenAccess ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.science/hal-00641423 Biogeosciences, 2011, 85, pp.2947-2959. ⟨10.5194/bg-8-2947-2011⟩ [SDE]Environmental Sciences info:eu-repo/semantics/article Journal articles 2011 ftinsu https://doi.org/10.5194/bg-8-2947-2011 2024-01-24T17:23:53Z International audience As part of the Bonus-GoodHope (BGH) campaign, 15N-labelled nitrate, ammonium and urea uptake measurements were made along the BGH transect from Cape Town to ~60° S in late austral summer, 2008. Our results are categorised according to distinct hydrographic regions defined by oceanic fronts and open ocean zones. High regenerated nitrate uptake rate in the oligotrophic Subtropical Zone (STZ) resulted in low f-ratios (f = 0.2) with nitrogen uptake being dominated by ρurea, which contributed up to 70 % of total nitrogen uptake. Size fractionated chlorophyll data showed that the greatest contribution (>50 %) of picophytoplankton (<2 μm) were found in the STZ, consistent with a community based on regenerated production. The Subantarctic Zone (SAZ) showed the greatest total integrated nitrogen uptake (10.3 mmol m−2 d−1), mainly due to enhanced nutrient supply within an anticyclonic eddy observed in this region. A decrease in the contribution of smaller size classes to the phytoplankton community was observed with increasing latitude, concurrent with a decrease in the contribution of regenerated production. Higher f-ratios observed in the SAZ (f = 0.49), Polar Frontal Zone (f= 0.41) and Antarctic Zone (f = 0.45) relative to the STZ (f = 0.24), indicate a higher contribution of NO3−-uptake relative to total nitrogen and potentially higher export production. High ambient regenerated nutrient concentrations are indicative of active regeneration processes throughout the transect and ascribed to late summer season sampling. Higher depth integrated uptake rates also correspond with higher surface iron concentrations. No clear correlation was observed between carbon export estimates derived from new production and 234Th flux. In addition, export derived from 15N estimates were 2-20 times greater than those based on 234Th flux. Variability in the magnitude of export is likely due to intrinsically different methods, compounded by differences in integration time scales for the two proxies of carbon ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Institut national des sciences de l'Univers: HAL-INSU Antarctic Austral Southern Ocean Biogeosciences 8 10 2947 2959 |