Exploring interacting influences on the silicon isotopic composition of the surface ocean: A case study from the Kerguelen Plateau
International audience This study presents six new water column profiles of the silicon isotopic composition (δ30Si) of dissolved silicon (DSi) from the Atlantic and Indian sectors of the Southern Ocean and a variable depth box model of silica cycling in the mixed layer that was constructed to illum...
Published in: | Biogeosciences |
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Main Authors: | , , |
Other Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2014
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Online Access: | https://hal.univ-brest.fr/hal-01025132 https://hal.univ-brest.fr/hal-01025132/document https://hal.univ-brest.fr/hal-01025132/file/bg-11-1371-2014.pdf https://doi.org/10.5194/bg-11-1371-2014 |
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ftunivbrest:oai:HAL:hal-01025132v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Université de Bretagne Occidentale: HAL |
op_collection_id |
ftunivbrest |
language |
English |
topic |
mixed layer numerical model observational method proxy climate record silica silicon Indian Ocean Kerguelen Plateau Southern Ocean ACL bioaccumulation chemical weathering concentration (composition) dissolution growth rate isotopic composition isotopic fractionation marine environment [SDV]Life Sciences [q-bio] [SDE.BE]Environmental Sciences/Biodiversity and Ecology |
spellingShingle |
mixed layer numerical model observational method proxy climate record silica silicon Indian Ocean Kerguelen Plateau Southern Ocean ACL bioaccumulation chemical weathering concentration (composition) dissolution growth rate isotopic composition isotopic fractionation marine environment [SDV]Life Sciences [q-bio] [SDE.BE]Environmental Sciences/Biodiversity and Ecology Coffineau, Nathalie de La Rocha, Christina L Pondaven, Philippe Exploring interacting influences on the silicon isotopic composition of the surface ocean: A case study from the Kerguelen Plateau |
topic_facet |
mixed layer numerical model observational method proxy climate record silica silicon Indian Ocean Kerguelen Plateau Southern Ocean ACL bioaccumulation chemical weathering concentration (composition) dissolution growth rate isotopic composition isotopic fractionation marine environment [SDV]Life Sciences [q-bio] [SDE.BE]Environmental Sciences/Biodiversity and Ecology |
description |
International audience This study presents six new water column profiles of the silicon isotopic composition (δ30Si) of dissolved silicon (DSi) from the Atlantic and Indian sectors of the Southern Ocean and a variable depth box model of silica cycling in the mixed layer that was constructed to illuminate the evolution of surface ocean δ30Si over the full course of a year. In keeping with previous observations, δ30Si values ranged from +1.9 to +2.4‰ in the mixed layer (ML), +1.2 to +1.7‰ in Winter Water (WW), and +0.9 to +1.4‰ in Circumpolar Deep Water (CDW). These data also confirmed the occurrence of diminished values for ML δ30Si at low DSi concentrations in early austral autumn on the Kerguelen Plateau. The box model was used to investigate whether these low, post-growing season values of δ30Si were related to input of DSi to the ML from basalt weathering, biogenic silica dissolution (with or without isotopic fractionation), the onset of winter mixing, or some combination of the three. Basalt weathering and fractionation during biogenic silica dissolution could both lower ML δ30Si below what would be expected from the extent of biological uptake of DSi. However, the key driver of the early autumn decrease in δ30Si appears to be the switch from bloom growth (with net removal of DSi and net accumulation of biogenic silica (BSi) biomass) to steady state growth (when slow but continuing production of BSi prevented significant net increase in DSi concentrations with diffusive input of DSi from WW but not decrease in ML δ30Si towards WW values). Model results also indicated that fractionation during dissolution has only a negligible effect on the δ30Si of BSi exported throughout the course of the year. However, seasonal changes in export efficiency (e.g. favouring the export of bloom BSi versus the export of BSi produced during other times of the year) should strongly influence the δ30Si of BSi accumulating in marine sediments. Finally, the choice for the parameterisation of the mixing between the ML and the WW ... |
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) |
format |
Article in Journal/Newspaper |
author |
Coffineau, Nathalie de La Rocha, Christina L Pondaven, Philippe |
author_facet |
Coffineau, Nathalie de La Rocha, Christina L Pondaven, Philippe |
author_sort |
Coffineau, Nathalie |
title |
Exploring interacting influences on the silicon isotopic composition of the surface ocean: A case study from the Kerguelen Plateau |
title_short |
Exploring interacting influences on the silicon isotopic composition of the surface ocean: A case study from the Kerguelen Plateau |
title_full |
Exploring interacting influences on the silicon isotopic composition of the surface ocean: A case study from the Kerguelen Plateau |
title_fullStr |
Exploring interacting influences on the silicon isotopic composition of the surface ocean: A case study from the Kerguelen Plateau |
title_full_unstemmed |
Exploring interacting influences on the silicon isotopic composition of the surface ocean: A case study from the Kerguelen Plateau |
title_sort |
exploring interacting influences on the silicon isotopic composition of the surface ocean: a case study from the kerguelen plateau |
publisher |
HAL CCSD |
publishDate |
2014 |
url |
https://hal.univ-brest.fr/hal-01025132 https://hal.univ-brest.fr/hal-01025132/document https://hal.univ-brest.fr/hal-01025132/file/bg-11-1371-2014.pdf https://doi.org/10.5194/bg-11-1371-2014 |
geographic |
Southern Ocean Austral Kerguelen Indian |
geographic_facet |
Southern Ocean Austral Kerguelen Indian |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.univ-brest.fr/hal-01025132 Biogeosciences, 2014, 11 (5), pp.1371-1391. ⟨10.5194/bg-11-1371-2014⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-11-1371-2014 hal-01025132 https://hal.univ-brest.fr/hal-01025132 https://hal.univ-brest.fr/hal-01025132/document https://hal.univ-brest.fr/hal-01025132/file/bg-11-1371-2014.pdf doi:10.5194/bg-11-1371-2014 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.5194/bg-11-1371-2014 |
container_title |
Biogeosciences |
container_volume |
11 |
container_issue |
5 |
container_start_page |
1371 |
op_container_end_page |
1391 |
_version_ |
1790608472046305280 |
spelling |
ftunivbrest:oai:HAL:hal-01025132v1 2024-02-11T10:08:51+01:00 Exploring interacting influences on the silicon isotopic composition of the surface ocean: A case study from the Kerguelen Plateau Coffineau, Nathalie de La Rocha, Christina L Pondaven, Philippe 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) 2014-03-12 https://hal.univ-brest.fr/hal-01025132 https://hal.univ-brest.fr/hal-01025132/document https://hal.univ-brest.fr/hal-01025132/file/bg-11-1371-2014.pdf https://doi.org/10.5194/bg-11-1371-2014 en eng HAL CCSD European Geosciences Union info:eu-repo/semantics/altIdentifier/doi/10.5194/bg-11-1371-2014 hal-01025132 https://hal.univ-brest.fr/hal-01025132 https://hal.univ-brest.fr/hal-01025132/document https://hal.univ-brest.fr/hal-01025132/file/bg-11-1371-2014.pdf doi:10.5194/bg-11-1371-2014 info:eu-repo/semantics/OpenAccess ISSN: 1726-4170 EISSN: 1726-4189 Biogeosciences https://hal.univ-brest.fr/hal-01025132 Biogeosciences, 2014, 11 (5), pp.1371-1391. ⟨10.5194/bg-11-1371-2014⟩ mixed layer numerical model observational method proxy climate record silica silicon Indian Ocean Kerguelen Plateau Southern Ocean ACL bioaccumulation chemical weathering concentration (composition) dissolution growth rate isotopic composition isotopic fractionation marine environment [SDV]Life Sciences [q-bio] [SDE.BE]Environmental Sciences/Biodiversity and Ecology info:eu-repo/semantics/article Journal articles 2014 ftunivbrest https://doi.org/10.5194/bg-11-1371-2014 2024-01-23T23:42:19Z International audience This study presents six new water column profiles of the silicon isotopic composition (δ30Si) of dissolved silicon (DSi) from the Atlantic and Indian sectors of the Southern Ocean and a variable depth box model of silica cycling in the mixed layer that was constructed to illuminate the evolution of surface ocean δ30Si over the full course of a year. In keeping with previous observations, δ30Si values ranged from +1.9 to +2.4‰ in the mixed layer (ML), +1.2 to +1.7‰ in Winter Water (WW), and +0.9 to +1.4‰ in Circumpolar Deep Water (CDW). These data also confirmed the occurrence of diminished values for ML δ30Si at low DSi concentrations in early austral autumn on the Kerguelen Plateau. The box model was used to investigate whether these low, post-growing season values of δ30Si were related to input of DSi to the ML from basalt weathering, biogenic silica dissolution (with or without isotopic fractionation), the onset of winter mixing, or some combination of the three. Basalt weathering and fractionation during biogenic silica dissolution could both lower ML δ30Si below what would be expected from the extent of biological uptake of DSi. However, the key driver of the early autumn decrease in δ30Si appears to be the switch from bloom growth (with net removal of DSi and net accumulation of biogenic silica (BSi) biomass) to steady state growth (when slow but continuing production of BSi prevented significant net increase in DSi concentrations with diffusive input of DSi from WW but not decrease in ML δ30Si towards WW values). Model results also indicated that fractionation during dissolution has only a negligible effect on the δ30Si of BSi exported throughout the course of the year. However, seasonal changes in export efficiency (e.g. favouring the export of bloom BSi versus the export of BSi produced during other times of the year) should strongly influence the δ30Si of BSi accumulating in marine sediments. Finally, the choice for the parameterisation of the mixing between the ML and the WW ... Article in Journal/Newspaper Southern Ocean Université de Bretagne Occidentale: HAL Southern Ocean Austral Kerguelen Indian Biogeosciences 11 5 1371 1391 |