Glacial heterogeneity in Southern Ocean carbon storage abated by fast South Indian deglacial carbon release

Abstract Past changes in ocean 14 C disequilibria have been suggested to reflect the Southern Ocean control on global exogenic carbon cycling. Yet, the volumetric extent of the glacial carbon pool and the deglacial mechanisms contributing to release remineralized carbon, particularly from regions wi...

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Bibliographic Details
Published in:Nature Communications
Main Authors: Gottschalk, Julia, Michel, Elisabeth, Thöle, Lena M., Studer, Anja S., Hasenfratz, Adam P., Schmid, Nicole, Butzin, Martin, Mazaud, Alain, Martínez-García, Alfredo, Szidat, Sönke, Jaccard, Samuel L.
Other Authors: Deutsche Forschungsgemeinschaft, Vetenskapsrådet, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
Format: Article in Journal/Newspaper
Language:English
Published: Springer Science and Business Media LLC 2020
Subjects:
General Physics and Astronomy
General Biochemistry, Genetics and Molecular Biology
General Chemistry
Indian
Kerguelen
Kerguelen Island
Southern Ocean
Online Access:http://dx.doi.org/10.1038/s41467-020-20034-1
http://www.nature.com/articles/s41467-020-20034-1.pdf
http://www.nature.com/articles/s41467-020-20034-1
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Summary:Abstract Past changes in ocean 14 C disequilibria have been suggested to reflect the Southern Ocean control on global exogenic carbon cycling. Yet, the volumetric extent of the glacial carbon pool and the deglacial mechanisms contributing to release remineralized carbon, particularly from regions with enhanced mixing today, remain insufficiently constrained. Here, we reconstruct the deglacial ventilation history of the South Indian upwelling hotspot near Kerguelen Island, using high-resolution 14 C-dating of smaller-than-conventional foraminiferal samples and multi-proxy deep-ocean oxygen estimates. We find marked regional differences in Southern Ocean overturning with distinct South Indian fingerprints on (early de-)glacial atmospheric CO 2 change. The dissipation of this heterogeneity commenced 14.6 kyr ago, signaling the onset of modern-like, strong South Indian Ocean upwelling, likely promoted by rejuvenated Atlantic overturning. Our findings highlight the South Indian Ocean’s capacity to influence atmospheric CO 2 levels and amplify the impacts of inter-hemispheric climate variability on global carbon cycling within centuries and millennia.

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