Ba distribution in surface Southern Ocean sediments and export production estimates
International audience We present excess Ba (Baxs) data (i.e., total Ba corrected for lithogenic Ba) for surface sediments from a north-south transect between the Polar Front Zone and the northern Weddell Gyre in the Atlantic sector and between the Polar Front Zone and the Antarctic continent in the...
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Other Authors: | , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2002
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Online Access: | https://hal.science/hal-00663036 |
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ftunivnantes:oai:HAL:hal-00663036v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
English |
topic |
Geochemistry: Marine geochemistry (4835 4850) Oceanography: Biological and Chemical: Inorganic marine chemistry [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDE.MCG]Environmental Sciences/Global Changes |
spellingShingle |
Geochemistry: Marine geochemistry (4835 4850) Oceanography: Biological and Chemical: Inorganic marine chemistry [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDE.MCG]Environmental Sciences/Global Changes Fagel, Nathalie Dehairs, Frank André, Luc Bareille, Gilles Monnin, Christophe Ba distribution in surface Southern Ocean sediments and export production estimates |
topic_facet |
Geochemistry: Marine geochemistry (4835 4850) Oceanography: Biological and Chemical: Inorganic marine chemistry [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDE.MCG]Environmental Sciences/Global Changes |
description |
International audience We present excess Ba (Baxs) data (i.e., total Ba corrected for lithogenic Ba) for surface sediments from a north-south transect between the Polar Front Zone and the northern Weddell Gyre in the Atlantic sector and between the Polar Front Zone and the Antarctic continent in the Indian sector. Focus is on two different processes that affect excess Ba accumulation in the sediments: sediment redistribution and excess Ba dissolution. The effect of these processes needs to be corrected for in order to convert accumulation rate into vertical rain rate, the flux component that can be linked to export production. In the Southern Ocean a major process affecting Ba accumulation rate is sediment focusing, which is corrected for using excess 230Th. This correction, however, may not always be straightforward because of boundary scavenging effects. A further major process affecting excess Ba accumulation is barite dissolution during exposure at the sediment-water column interface. Export production estimates derived from excess 230Th and barite dissolution corrected Baxs accumulation rates (i.e., excess Ba vertical rain rates) are of the same magnitude but generally larger than export production estimates based on water column proxies (234Th-deficit in the upper water column; particulate excess Ba enrichment in the mesopelagic water column). We believe export production values based on excess Ba vertical rain rate might be overestimated due to inaccurate assessment of the Baxs preservation rate. Barite dissolution has, in general, been taken into account by relating it to exposure time before burial depending on the rate of sediment accumulation. However, the observed decrease of excess Ba content with increasing water column depth (or increasing hydrostatic pressure) illustrates the dependence of barite preservation on degree of saturation in the deep water column in accordance with available thermodynamic data. Therefore correction for barite dissolution would not be appropriate by considering only ... |
author2 |
Argiles, Géochimie et Environnement sédimentaires Université de Liège Analytical and Environmental Chemistry and Earth System Sciences Vrije Universiteit Brussel (VUB) Geology and mineralogy, section of Mineralogy and Petrography Royal Museum for Central Africa Tervuren (RMCA) Geology and Oceanography Department Université de Bordeaux (UB) Laboratoire des Mécanismes et Transfert en Géologie (LMTG) Université Toulouse III - Paul Sabatier (UT3) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP) 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)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Fagel, Nathalie Dehairs, Frank André, Luc Bareille, Gilles Monnin, Christophe |
author_facet |
Fagel, Nathalie Dehairs, Frank André, Luc Bareille, Gilles Monnin, Christophe |
author_sort |
Fagel, Nathalie |
title |
Ba distribution in surface Southern Ocean sediments and export production estimates |
title_short |
Ba distribution in surface Southern Ocean sediments and export production estimates |
title_full |
Ba distribution in surface Southern Ocean sediments and export production estimates |
title_fullStr |
Ba distribution in surface Southern Ocean sediments and export production estimates |
title_full_unstemmed |
Ba distribution in surface Southern Ocean sediments and export production estimates |
title_sort |
ba distribution in surface southern ocean sediments and export production estimates |
publisher |
HAL CCSD |
publishDate |
2002 |
url |
https://hal.science/hal-00663036 |
geographic |
Antarctic Southern Ocean The Antarctic Indian Weddell |
geographic_facet |
Antarctic Southern Ocean The Antarctic Indian Weddell |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
ISSN: 0883-8305 Paleoceanography https://hal.science/hal-00663036 Paleoceanography, 2002, 17, pp.1-1 |
op_relation |
hal-00663036 https://hal.science/hal-00663036 BIBCODE: 2002PalOc.17b.1F |
_version_ |
1766266555160592384 |
spelling |
ftunivnantes:oai:HAL:hal-00663036v1 2023-05-15T13:58:19+02:00 Ba distribution in surface Southern Ocean sediments and export production estimates Fagel, Nathalie Dehairs, Frank André, Luc Bareille, Gilles Monnin, Christophe Argiles, Géochimie et Environnement sédimentaires Université de Liège Analytical and Environmental Chemistry and Earth System Sciences Vrije Universiteit Brussel (VUB) Geology and mineralogy, section of Mineralogy and Petrography Royal Museum for Central Africa Tervuren (RMCA) Geology and Oceanography Department Université de Bordeaux (UB) Laboratoire des Mécanismes et Transfert en Géologie (LMTG) Université Toulouse III - Paul Sabatier (UT3) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP) 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)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS) 2002-03 https://hal.science/hal-00663036 en eng HAL CCSD American Geophysical Union hal-00663036 https://hal.science/hal-00663036 BIBCODE: 2002PalOc.17b.1F ISSN: 0883-8305 Paleoceanography https://hal.science/hal-00663036 Paleoceanography, 2002, 17, pp.1-1 Geochemistry: Marine geochemistry (4835 4850) Oceanography: Biological and Chemical: Inorganic marine chemistry [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [SDE.MCG]Environmental Sciences/Global Changes info:eu-repo/semantics/article Journal articles 2002 ftunivnantes 2023-02-22T00:13:57Z International audience We present excess Ba (Baxs) data (i.e., total Ba corrected for lithogenic Ba) for surface sediments from a north-south transect between the Polar Front Zone and the northern Weddell Gyre in the Atlantic sector and between the Polar Front Zone and the Antarctic continent in the Indian sector. Focus is on two different processes that affect excess Ba accumulation in the sediments: sediment redistribution and excess Ba dissolution. The effect of these processes needs to be corrected for in order to convert accumulation rate into vertical rain rate, the flux component that can be linked to export production. In the Southern Ocean a major process affecting Ba accumulation rate is sediment focusing, which is corrected for using excess 230Th. This correction, however, may not always be straightforward because of boundary scavenging effects. A further major process affecting excess Ba accumulation is barite dissolution during exposure at the sediment-water column interface. Export production estimates derived from excess 230Th and barite dissolution corrected Baxs accumulation rates (i.e., excess Ba vertical rain rates) are of the same magnitude but generally larger than export production estimates based on water column proxies (234Th-deficit in the upper water column; particulate excess Ba enrichment in the mesopelagic water column). We believe export production values based on excess Ba vertical rain rate might be overestimated due to inaccurate assessment of the Baxs preservation rate. Barite dissolution has, in general, been taken into account by relating it to exposure time before burial depending on the rate of sediment accumulation. However, the observed decrease of excess Ba content with increasing water column depth (or increasing hydrostatic pressure) illustrates the dependence of barite preservation on degree of saturation in the deep water column in accordance with available thermodynamic data. Therefore correction for barite dissolution would not be appropriate by considering only ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Université de Nantes: HAL-UNIV-NANTES Antarctic Southern Ocean The Antarctic Indian Weddell |