Glacial-interglacial dust and export production records from the Southern Indian Ocean
We present 230 Th-normalized dust and export production fluxes for two contrasted marine sediment cores spanning the Antarctic Polar Front, close to the Kerguelen Plateau in the Southern Indian Ocean, covering the last glacial cycle. We report glacial lithogenic fluxes comparable to the South Atlant...
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ftpubman:oai:pure.mpg.de:item_3215621 2023-08-27T04:06:13+02:00 Glacial-interglacial dust and export production records from the Southern Indian Ocean Thole, L. Amsler, H. Moretti, S. Auderset, A. Gilgannon, J. Lippold, J. Vogel, H. Crosta, X. Mazaud, A. Michel, E. Martinez-Garcia, A. Jaccard, S. 2019 http://hdl.handle.net/21.11116/0000-0005-F0B9-B unknown info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2019.115716 http://hdl.handle.net/21.11116/0000-0005-F0B9-B Earth and Planetary Science Letters info:eu-repo/semantics/article 2019 ftpubman https://doi.org/10.1016/j.epsl.2019.115716 2023-08-02T00:15:17Z We present 230 Th-normalized dust and export production fluxes for two contrasted marine sediment cores spanning the Antarctic Polar Front, close to the Kerguelen Plateau in the Southern Indian Ocean, covering the last glacial cycle. We report glacial lithogenic fluxes comparable to the South Atlantic and higher than in the South Pacific sectors of the Southern Ocean. Structural and temporal discrepancies with dust reconstructions from Antarctic ice cores and the Atlantic and Pacific sectors of the Subantarctic Zone (SAZ) point towards Southern Africa and/or the Kerguelen Plateau as an additional source of lithogenic material to the Southern Indian Ocean during the last ice age. In the SAZ, export production proxies respond to iron (Fe) fertilization with total organic carbon (TOC) fluxes as high as those previously reported from the Atlantic sector of the Southern Ocean. However, the correlation between export production and dust proxies is weaker than in the other sectors, and shows a muted response of export production during peak glacials. We hypothesize that this muted response may be related to macronutrient (co-)limitation imposed on phytoplankton growth possibly induced by a northward displacement of wind-driven upwelling and/or the polar frontal system during peak glacials. The Antarctic Zone (AZ) record depicts the typical pattern of enhanced export production during interglacials and comparatively low productivity during glacials suggesting a decrease in the supply of macronutrients to the AZ surface during ice ages compared to warm periods, as previously proposed. However, a muted response of opal fluxes during marine isotope stage (MIS) 5e argues for a southward migration of the frontal system during warmer MIS 5e, possibly causing silicic acid (co-)limitation at this site. These results illustrate the important role of Fe fertilization and changes in wind-driven upwelling intensities in modulating the strength and efficiency of the biological carbon pump in the Southern Ocean, but also highlight ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Max Planck Society: MPG.PuRe Antarctic Indian Kerguelen Pacific Southern Ocean The Antarctic Earth and Planetary Science Letters 525 115716 |
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Open Polar |
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Max Planck Society: MPG.PuRe |
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ftpubman |
language |
unknown |
description |
We present 230 Th-normalized dust and export production fluxes for two contrasted marine sediment cores spanning the Antarctic Polar Front, close to the Kerguelen Plateau in the Southern Indian Ocean, covering the last glacial cycle. We report glacial lithogenic fluxes comparable to the South Atlantic and higher than in the South Pacific sectors of the Southern Ocean. Structural and temporal discrepancies with dust reconstructions from Antarctic ice cores and the Atlantic and Pacific sectors of the Subantarctic Zone (SAZ) point towards Southern Africa and/or the Kerguelen Plateau as an additional source of lithogenic material to the Southern Indian Ocean during the last ice age. In the SAZ, export production proxies respond to iron (Fe) fertilization with total organic carbon (TOC) fluxes as high as those previously reported from the Atlantic sector of the Southern Ocean. However, the correlation between export production and dust proxies is weaker than in the other sectors, and shows a muted response of export production during peak glacials. We hypothesize that this muted response may be related to macronutrient (co-)limitation imposed on phytoplankton growth possibly induced by a northward displacement of wind-driven upwelling and/or the polar frontal system during peak glacials. The Antarctic Zone (AZ) record depicts the typical pattern of enhanced export production during interglacials and comparatively low productivity during glacials suggesting a decrease in the supply of macronutrients to the AZ surface during ice ages compared to warm periods, as previously proposed. However, a muted response of opal fluxes during marine isotope stage (MIS) 5e argues for a southward migration of the frontal system during warmer MIS 5e, possibly causing silicic acid (co-)limitation at this site. These results illustrate the important role of Fe fertilization and changes in wind-driven upwelling intensities in modulating the strength and efficiency of the biological carbon pump in the Southern Ocean, but also highlight ... |
format |
Article in Journal/Newspaper |
author |
Thole, L. Amsler, H. Moretti, S. Auderset, A. Gilgannon, J. Lippold, J. Vogel, H. Crosta, X. Mazaud, A. Michel, E. Martinez-Garcia, A. Jaccard, S. |
spellingShingle |
Thole, L. Amsler, H. Moretti, S. Auderset, A. Gilgannon, J. Lippold, J. Vogel, H. Crosta, X. Mazaud, A. Michel, E. Martinez-Garcia, A. Jaccard, S. Glacial-interglacial dust and export production records from the Southern Indian Ocean |
author_facet |
Thole, L. Amsler, H. Moretti, S. Auderset, A. Gilgannon, J. Lippold, J. Vogel, H. Crosta, X. Mazaud, A. Michel, E. Martinez-Garcia, A. Jaccard, S. |
author_sort |
Thole, L. |
title |
Glacial-interglacial dust and export production records from the Southern Indian Ocean |
title_short |
Glacial-interglacial dust and export production records from the Southern Indian Ocean |
title_full |
Glacial-interglacial dust and export production records from the Southern Indian Ocean |
title_fullStr |
Glacial-interglacial dust and export production records from the Southern Indian Ocean |
title_full_unstemmed |
Glacial-interglacial dust and export production records from the Southern Indian Ocean |
title_sort |
glacial-interglacial dust and export production records from the southern indian ocean |
publishDate |
2019 |
url |
http://hdl.handle.net/21.11116/0000-0005-F0B9-B |
geographic |
Antarctic Indian Kerguelen Pacific Southern Ocean The Antarctic |
geographic_facet |
Antarctic Indian Kerguelen Pacific Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
Earth and Planetary Science Letters |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2019.115716 http://hdl.handle.net/21.11116/0000-0005-F0B9-B |
op_doi |
https://doi.org/10.1016/j.epsl.2019.115716 |
container_title |
Earth and Planetary Science Letters |
container_volume |
525 |
container_start_page |
115716 |
_version_ |
1775347025040113664 |