Low particulate organic carbon export in the frontal zone of the Southern Ocean (Indian Sector) revealed by 234Th
The water column deficiencies of 234Th were used to estimate the Particulate Organic Carbon (POC) fluxes in the Indian Sector of the Southern Ocean. Samples were collected in January–February 1999 in a frontal zone from 42°S to 47°S and from 60°E to 66°E during the ANTARES 4 cruise. Beta counting wa...
Published in: | Deep Sea Research Part I: Oceanographic Research Papers |
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Main Authors: | , , , , |
Other Authors: | , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2005
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Subjects: | |
Online Access: | https://hal.archives-ouvertes.fr/hal-00280197 https://doi.org/10.1016/j.dsr.2004.07.020 |
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Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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English |
topic |
Thorium-234 POC export Southern Ocean [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
spellingShingle |
Thorium-234 POC export Southern Ocean [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry Coppola, L. Roy-Barman, M. Mulsow, S. Povinec, P. Jeandel, C. Low particulate organic carbon export in the frontal zone of the Southern Ocean (Indian Sector) revealed by 234Th |
topic_facet |
Thorium-234 POC export Southern Ocean [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
description |
The water column deficiencies of 234Th were used to estimate the Particulate Organic Carbon (POC) fluxes in the Indian Sector of the Southern Ocean. Samples were collected in January–February 1999 in a frontal zone from 42°S to 47°S and from 60°E to 66°E during the ANTARES 4 cruise. Beta counting was used to measure the 234Th activities onboard. The 234Th export fluxes were estimated from the 234Th/238U disequilibria using a steady state 234Th model. A non-steady state model gave results close to the steady-state model in the Subtropical Zone and could not be used in the Subantarctic Zone due to a strong vertical mixing event. Small and large particles analysis indicated that the POC/234Th ratios decreased when the particle size increased. From the POC/234Th ratios on the large filtered particles, it appears that the POC export fluxes exported below 100 m were very low (from 0.10 to 2.53 mmolC m−2 d−1) compared to those observed in the Southern Ocean and (Deep Sea Res. II 48 (2001) 4275; Deep Sea Res. II 47 (15–16) (2000) 3451; Deep Sea Res. II 44 (1997) 457) and with a strong zonal variation . It is hypothesized that the low POC export fluxes were related to the low predominance of diatoms, characteristic at the end of a bloom period. In this way, the very low POC export observed in the Subtropical Zone suggests an efficient remineralization process and/or a high bacterial activity. Otherwise, a decoupling between the primary production and the POC export derived from 234Th could also explain the low POC export. |
author2 |
Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS) Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) Géochimie Des Impacts (GEDI) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) IAEA Marine Environment Laboratory Marine Environment Laboratories Monaco (IAEA-MEL) International Atomic Energy Agency Vienna (IAEA) |
format |
Article in Journal/Newspaper |
author |
Coppola, L. Roy-Barman, M. Mulsow, S. Povinec, P. Jeandel, C. |
author_facet |
Coppola, L. Roy-Barman, M. Mulsow, S. Povinec, P. Jeandel, C. |
author_sort |
Coppola, L. |
title |
Low particulate organic carbon export in the frontal zone of the Southern Ocean (Indian Sector) revealed by 234Th |
title_short |
Low particulate organic carbon export in the frontal zone of the Southern Ocean (Indian Sector) revealed by 234Th |
title_full |
Low particulate organic carbon export in the frontal zone of the Southern Ocean (Indian Sector) revealed by 234Th |
title_fullStr |
Low particulate organic carbon export in the frontal zone of the Southern Ocean (Indian Sector) revealed by 234Th |
title_full_unstemmed |
Low particulate organic carbon export in the frontal zone of the Southern Ocean (Indian Sector) revealed by 234Th |
title_sort |
low particulate organic carbon export in the frontal zone of the southern ocean (indian sector) revealed by 234th |
publisher |
HAL CCSD |
publishDate |
2005 |
url |
https://hal.archives-ouvertes.fr/hal-00280197 https://doi.org/10.1016/j.dsr.2004.07.020 |
geographic |
Southern Ocean Indian |
geographic_facet |
Southern Ocean Indian |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
ISSN: 0967-0637 Deep Sea Research Part I: Oceanographic Research Papers https://hal.archives-ouvertes.fr/hal-00280197 Deep Sea Research Part I: Oceanographic Research Papers, Elsevier, 2005, 52, pp.51-68. ⟨10.1016/j.dsr.2004.07.020⟩ |
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info:eu-repo/semantics/altIdentifier/doi/10.1016/j.dsr.2004.07.020 hal-00280197 https://hal.archives-ouvertes.fr/hal-00280197 doi:10.1016/j.dsr.2004.07.020 |
op_doi |
https://doi.org/10.1016/j.dsr.2004.07.020 |
container_title |
Deep Sea Research Part I: Oceanographic Research Papers |
container_volume |
52 |
container_issue |
1 |
container_start_page |
51 |
op_container_end_page |
68 |
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1766205659902115840 |
spelling |
ftccsdartic:oai:HAL:hal-00280197v1 2023-05-15T18:24:46+02:00 Low particulate organic carbon export in the frontal zone of the Southern Ocean (Indian Sector) revealed by 234Th Coppola, L. Roy-Barman, M. Mulsow, S. Povinec, P. Jeandel, C. Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS) Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) Géochimie Des Impacts (GEDI) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) IAEA Marine Environment Laboratory Marine Environment Laboratories Monaco (IAEA-MEL) International Atomic Energy Agency Vienna (IAEA) 2005 https://hal.archives-ouvertes.fr/hal-00280197 https://doi.org/10.1016/j.dsr.2004.07.020 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.dsr.2004.07.020 hal-00280197 https://hal.archives-ouvertes.fr/hal-00280197 doi:10.1016/j.dsr.2004.07.020 ISSN: 0967-0637 Deep Sea Research Part I: Oceanographic Research Papers https://hal.archives-ouvertes.fr/hal-00280197 Deep Sea Research Part I: Oceanographic Research Papers, Elsevier, 2005, 52, pp.51-68. ⟨10.1016/j.dsr.2004.07.020⟩ Thorium-234 POC export Southern Ocean [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry info:eu-repo/semantics/article Journal articles 2005 ftccsdartic https://doi.org/10.1016/j.dsr.2004.07.020 2021-12-19T04:13:17Z The water column deficiencies of 234Th were used to estimate the Particulate Organic Carbon (POC) fluxes in the Indian Sector of the Southern Ocean. Samples were collected in January–February 1999 in a frontal zone from 42°S to 47°S and from 60°E to 66°E during the ANTARES 4 cruise. Beta counting was used to measure the 234Th activities onboard. The 234Th export fluxes were estimated from the 234Th/238U disequilibria using a steady state 234Th model. A non-steady state model gave results close to the steady-state model in the Subtropical Zone and could not be used in the Subantarctic Zone due to a strong vertical mixing event. Small and large particles analysis indicated that the POC/234Th ratios decreased when the particle size increased. From the POC/234Th ratios on the large filtered particles, it appears that the POC export fluxes exported below 100 m were very low (from 0.10 to 2.53 mmolC m−2 d−1) compared to those observed in the Southern Ocean and (Deep Sea Res. II 48 (2001) 4275; Deep Sea Res. II 47 (15–16) (2000) 3451; Deep Sea Res. II 44 (1997) 457) and with a strong zonal variation . It is hypothesized that the low POC export fluxes were related to the low predominance of diatoms, characteristic at the end of a bloom period. In this way, the very low POC export observed in the Subtropical Zone suggests an efficient remineralization process and/or a high bacterial activity. Otherwise, a decoupling between the primary production and the POC export derived from 234Th could also explain the low POC export. Article in Journal/Newspaper Southern Ocean Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Southern Ocean Indian Deep Sea Research Part I: Oceanographic Research Papers 52 1 51 68 |