The silicon isotopic composition of surface waters in the Atlantic and Indian sectors of the Southern Ocean
International audience We report here the silicon isotopic composition (d30Si) of dissolved silicon (DSi) from 42 surface water samples from the Drake Passage, the Weddell Gyre, other areas south of the Southern Boundary of the Antarctic Circumpolar Current (ACC), and the ACC near the Kerguelen Plat...
Published in: | Geochimica et Cosmochimica Acta |
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ftunivbrest:oai:HAL:hal-00660777v1 2024-04-28T08:00:31+00:00 The silicon isotopic composition of surface waters in the Atlantic and Indian sectors of the Southern Ocean de La Rocha, Christina, L. Bescont, Pierre Croguennoc, Alice Ponzevera, Emmanuel 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) Unité Géosciences Marines (GM) Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) LEFE-CYBER (project SIMS) 2011 https://hal.univ-brest.fr/hal-00660777 https://doi.org/10.1016/j.gca.2011.06.028 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.gca.2011.06.028 hal-00660777 https://hal.univ-brest.fr/hal-00660777 doi:10.1016/j.gca.2011.06.028 ISSN: 0016-7037 EISSN: 0016-7037 Geochimica et Cosmochimica Acta https://hal.univ-brest.fr/hal-00660777 Geochimica et Cosmochimica Acta, 2011, 75, pp.5283-5295. ⟨10.1016/j.gca.2011.06.028⟩ silicon isotopes Southern Ocean [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/article Journal articles 2011 ftunivbrest https://doi.org/10.1016/j.gca.2011.06.028 2024-04-10T23:44:46Z International audience We report here the silicon isotopic composition (d30Si) of dissolved silicon (DSi) from 42 surface water samples from the Drake Passage, the Weddell Gyre, other areas south of the Southern Boundary of the Antarctic Circumpolar Current (ACC), and the ACC near the Kerguelen Plateau, taken between the beginning of February and the end of March 2007. From the beginning to end of the cruise (ANTXXIII/9), DSi diminished in the Antarctic by 50 umol L-1 while concentrations of nitrate + nitrite and phosphate showed no net decline, indicating that the high seasonal Si/N removal ratios well known for the Southern Ocean may be more related to the strength of the silicate pump in the Southern Ocean than to the instantaneous Si/N uptake ratio of diatoms. The d30Si of DSi in samples containing more than 20 lM DSi were strongly negatively correlated to DSi concentrations, supporting the use of d30Si as a proxy for DSi removal. The "open system" fractionation observed, e = -1.2 ± 0.11&, agrees well with results from previous work in other areas, and the estimate of the initial d30Si of DSi of +1.4& is not far off observations of the d30Si of DSi in Winter Water (WW) in this area. Results were used to model DSi draw down in the past from the d30Si of sediment cores, although isotopic fractionation during silica dissolution appeared to influence the d30Si of some surface water samples, inviting further study of this phenomenon. Article in Journal/Newspaper Antarc* Antarctic Drake Passage Southern Ocean Université de Bretagne Occidentale: HAL Geochimica et Cosmochimica Acta 75 18 5283 5295 |
institution |
Open Polar |
collection |
Université de Bretagne Occidentale: HAL |
op_collection_id |
ftunivbrest |
language |
English |
topic |
silicon isotopes Southern Ocean [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
silicon isotopes Southern Ocean [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography de La Rocha, Christina, L. Bescont, Pierre Croguennoc, Alice Ponzevera, Emmanuel The silicon isotopic composition of surface waters in the Atlantic and Indian sectors of the Southern Ocean |
topic_facet |
silicon isotopes Southern Ocean [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
International audience We report here the silicon isotopic composition (d30Si) of dissolved silicon (DSi) from 42 surface water samples from the Drake Passage, the Weddell Gyre, other areas south of the Southern Boundary of the Antarctic Circumpolar Current (ACC), and the ACC near the Kerguelen Plateau, taken between the beginning of February and the end of March 2007. From the beginning to end of the cruise (ANTXXIII/9), DSi diminished in the Antarctic by 50 umol L-1 while concentrations of nitrate + nitrite and phosphate showed no net decline, indicating that the high seasonal Si/N removal ratios well known for the Southern Ocean may be more related to the strength of the silicate pump in the Southern Ocean than to the instantaneous Si/N uptake ratio of diatoms. The d30Si of DSi in samples containing more than 20 lM DSi were strongly negatively correlated to DSi concentrations, supporting the use of d30Si as a proxy for DSi removal. The "open system" fractionation observed, e = -1.2 ± 0.11&, agrees well with results from previous work in other areas, and the estimate of the initial d30Si of DSi of +1.4& is not far off observations of the d30Si of DSi in Winter Water (WW) in this area. Results were used to model DSi draw down in the past from the d30Si of sediment cores, although isotopic fractionation during silica dissolution appeared to influence the d30Si of some surface water samples, inviting further study of this phenomenon. |
author2 |
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) Unité Géosciences Marines (GM) Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) LEFE-CYBER (project SIMS) |
format |
Article in Journal/Newspaper |
author |
de La Rocha, Christina, L. Bescont, Pierre Croguennoc, Alice Ponzevera, Emmanuel |
author_facet |
de La Rocha, Christina, L. Bescont, Pierre Croguennoc, Alice Ponzevera, Emmanuel |
author_sort |
de La Rocha, Christina, L. |
title |
The silicon isotopic composition of surface waters in the Atlantic and Indian sectors of the Southern Ocean |
title_short |
The silicon isotopic composition of surface waters in the Atlantic and Indian sectors of the Southern Ocean |
title_full |
The silicon isotopic composition of surface waters in the Atlantic and Indian sectors of the Southern Ocean |
title_fullStr |
The silicon isotopic composition of surface waters in the Atlantic and Indian sectors of the Southern Ocean |
title_full_unstemmed |
The silicon isotopic composition of surface waters in the Atlantic and Indian sectors of the Southern Ocean |
title_sort |
silicon isotopic composition of surface waters in the atlantic and indian sectors of the southern ocean |
publisher |
HAL CCSD |
publishDate |
2011 |
url |
https://hal.univ-brest.fr/hal-00660777 https://doi.org/10.1016/j.gca.2011.06.028 |
genre |
Antarc* Antarctic Drake Passage Southern Ocean |
genre_facet |
Antarc* Antarctic Drake Passage Southern Ocean |
op_source |
ISSN: 0016-7037 EISSN: 0016-7037 Geochimica et Cosmochimica Acta https://hal.univ-brest.fr/hal-00660777 Geochimica et Cosmochimica Acta, 2011, 75, pp.5283-5295. ⟨10.1016/j.gca.2011.06.028⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.gca.2011.06.028 hal-00660777 https://hal.univ-brest.fr/hal-00660777 doi:10.1016/j.gca.2011.06.028 |
op_doi |
https://doi.org/10.1016/j.gca.2011.06.028 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
75 |
container_issue |
18 |
container_start_page |
5283 |
op_container_end_page |
5295 |
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