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

Type Article
Date 2020-12
Language English
Author(s) Gottschalk Julia1, 2, Michel Elisabeth3, Thöle Lena M.1, 4, Studer Anja S.5, 6, Hasenfratz Adam P.1, 7, Schmid Nicole1, Butzin Martin8, Mazaud Alain3, Martínez-García Alfredo5, Szidat Sönke9, Jaccard Samuel L.1
Affiliation(s) 1 : Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland
2 : Lamont-Doherty Earth Observatory, Columbia University of the City of New York, Palisades, NY, USA
3 : Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL, CNRS-CEA-UVSQ, Université de Paris-Saclay, Gif-sur-Yvette, France
4 : Department of Earth Sciences, Marine Palynology and Paleoceanography, Utrecht University, Utrecht, Netherlands
5 : Max Planck Institute for Chemistry, Climate Geochemistry Department, Mainz, Germany
6 : Department of Environmental Sciences, University of Basel, Basel, Switzerland
7 : Geological Institute, Department of Earth Sciences, ETH Zurich, Zurich, Switzerland
8 : Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung, Bremerhaven, Germany
9 : Department of Chemistry and Biochemistry and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
Source Nature Communications (2041-1723) (Springer Science and Business Media LLC), 2020-12 , Vol. 11 , N. 1 , P. 6192 (14p.)
DOI 10.1038/s41467-020-20034-1
Abstract

Past changes in ocean 14C 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 14C-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 CO2 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 CO2 levels and amplify the impacts of inter-hemispheric climate variability on global carbon cycling within centuries and millennia.

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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. (2020). Glacial heterogeneity in Southern Ocean carbon storage abated by fast South Indian deglacial carbon release. Nature Communications, 11(1), 6192 (14p.). Publisher's official version : https://doi.org/10.1038/s41467-020-20034-1 , Open Access version : https://archimer.ifremer.fr/doc/00662/77418/