Bottom water oxygenation changes in the southwestern Indian Ocean as an indicator for enhanced respired carbon storage since the last glacial inception

Amsler, Eri; Thöle, Lena Mareike; Stimac, Ingrid; Geibert, Walter; Ikehara, Minoru; Kuhn, Gerhard; Esper, Oliver; Jaccard, Samuel Laurent (2022). Bottom water oxygenation changes in the southwestern Indian Ocean as an indicator for enhanced respired carbon storage since the last glacial inception. Climate of the past, 18(8), pp. 1797-1813. Copernicus Publications 10.5194/cp-18-1797-2022

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We present downcore records of redox-sensitive authigenic uranium (U) and manganese (Mn) concentrations based on five marine sediment cores spanning a meridional transect encompassing the Subantarctic and Antarctic zones in the southwestern Indian Ocean covering the last glacial cycle. These records signal lower bottom water oxygenation during glacial climate intervals and generally higher oxygenation during warm periods, consistent with climaterelated changes in deep-ocean remineralized carbon storage. Regional changes in the export of siliceous phytoplankton to the deep sea may have entailed a secondary influence on oxygen levels at the water–sediment interface, especially
in the Subantarctic Zone. The rapid reoxygenation during the deglaciation is in line with increased ventilation and enhanced upwelling after the Last Glacial Maximum (LGM), which in combination conspired to transfer previously sequestered remineralized carbon to the surface ocean and the atmosphere, contributing to propel the Earth’s climate out of the last ice age. These records highlight the still insufficiently documented role that the Southern Indian Ocean played in the air–sea partitioning of CO2 on glacial–interglacial timescales.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geological Sciences
13 Central Units > Administrative Director's Office > University Library of Bern > Libraries > Medicine and Natural Sciences Section > Exact Sciences

UniBE Contributor:

Amsler, Eri; Thöle, Lena and Jaccard, Samuel

Subjects:

500 Science > 550 Earth sciences & geology
000 Computer science, knowledge & systems > 020 Library & information sciences

ISSN:

1814-9332

Publisher:

Copernicus Publications

Funders:

[4] Swiss National Science Foundation

Language:

English

Submitter:

Helen Eri Amsler

Date Deposited:

12 Aug 2022 09:44

Last Modified:

12 Aug 2022 09:44

Publisher DOI:

10.5194/cp-18-1797-2022

BORIS DOI:

10.48350/171563

URI:

https://boris.unibe.ch/id/eprint/171563

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