Exploring interacting influences on the silicon isotopic composition of the surface ocean: a case study from the Kerguelen Plateau
This study presents six new water column profiles of the silicon isotopic composition (delta Si-30) 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 evoluti...
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fttriple:oai:gotriple.eu:10670/1.ntcukr 2023-05-15T18:25:56+02:00 Exploring interacting influences on the silicon isotopic composition of the surface ocean: a case study from the Kerguelen Plateau Coffineau, N. De La Rocha, C. L. Pondaven, Philippe 2014-01-01 https://doi.org/10.5194/bg-11-1371-2014 https://archimer.ifremer.fr/doc/00260/37171/35691.pdf https://archimer.ifremer.fr/doc/00260/37171/ en eng Copernicus Gesellschaft Mbh doi:10.5194/bg-11-1371-2014 10670/1.ntcukr https://archimer.ifremer.fr/doc/00260/37171/35691.pdf https://archimer.ifremer.fr/doc/00260/37171/ lic_creative-commons other Archimer, archive institutionnelle de l'Ifremer Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2014 , Vol. 11 , N. 5 , P. 1371-1391 anthro-se envir Text https://vocabularies.coar-repositories.org/resource_types/c_18cf/ 2014 fttriple https://doi.org/10.5194/bg-11-1371-2014 2023-01-22T18:24:12Z This study presents six new water column profiles of the silicon isotopic composition (delta Si-30) 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 delta Si-30 over the full course of a year. In keeping with previous observations, delta Si-30 values ranged from +1.9 to +2.4% in the mixed layer (ML), +1.2 to +1.7 parts per thousand in Winter Water (WW), and +0.9 to +1.4 parts per thousand in Circumpolar Deep Water (CDW). These data also confirmed the occurrence of diminished values for ML delta Si-30 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 delta Si-30 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 delta Si-30 below what would be expected from the extent of biological uptake of DSi. However, the key driver of the early autumn decrease in delta Si-30 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 delta Si-30 towards WW values). Model results also indicated that fractionation during dissolution has only a negligible effect on the delta Si-30 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 delta Si-30 of BSi accumulating in marine sediments. Finally, the ... Text Southern Ocean Unknown Austral Indian Kerguelen Southern Ocean Biogeosciences 11 5 1371 1391 |
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anthro-se envir Coffineau, N. De La Rocha, C. L. Pondaven, Philippe Exploring interacting influences on the silicon isotopic composition of the surface ocean: a case study from the Kerguelen Plateau |
topic_facet |
anthro-se envir |
description |
This study presents six new water column profiles of the silicon isotopic composition (delta Si-30) 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 delta Si-30 over the full course of a year. In keeping with previous observations, delta Si-30 values ranged from +1.9 to +2.4% in the mixed layer (ML), +1.2 to +1.7 parts per thousand in Winter Water (WW), and +0.9 to +1.4 parts per thousand in Circumpolar Deep Water (CDW). These data also confirmed the occurrence of diminished values for ML delta Si-30 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 delta Si-30 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 delta Si-30 below what would be expected from the extent of biological uptake of DSi. However, the key driver of the early autumn decrease in delta Si-30 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 delta Si-30 towards WW values). Model results also indicated that fractionation during dissolution has only a negligible effect on the delta Si-30 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 delta Si-30 of BSi accumulating in marine sediments. Finally, the ... |
format |
Text |
author |
Coffineau, N. De La Rocha, C. L. Pondaven, Philippe |
author_facet |
Coffineau, N. De La Rocha, C. L. Pondaven, Philippe |
author_sort |
Coffineau, N. |
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 |
Copernicus Gesellschaft Mbh |
publishDate |
2014 |
url |
https://doi.org/10.5194/bg-11-1371-2014 https://archimer.ifremer.fr/doc/00260/37171/35691.pdf https://archimer.ifremer.fr/doc/00260/37171/ |
geographic |
Austral Indian Kerguelen Southern Ocean |
geographic_facet |
Austral Indian Kerguelen Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Archimer, archive institutionnelle de l'Ifremer Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2014 , Vol. 11 , N. 5 , P. 1371-1391 |
op_relation |
doi:10.5194/bg-11-1371-2014 10670/1.ntcukr https://archimer.ifremer.fr/doc/00260/37171/35691.pdf https://archimer.ifremer.fr/doc/00260/37171/ |
op_rights |
lic_creative-commons other |
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 |
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1766207668961148928 |