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Biological and physical controls in the Southern Ocean on past millennial-scale atmospheric CO2 changes

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Gottschalk Julia, Skinner Luke C., Lippold Jörg, Vogel Hendrik, Frank Norbert, Jaccard Samuel L., Waelbroeck Claire,
Project SeaO2 - Past changes in Southern Ocean overturning circulation - implications for the partitioning of carbon and oxygen between the ocean and the atmosphere
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Original article (peer-reviewed)

Journal Nature Communications
Volume (Issue) 7(11539)
Page(s) 1 - 11
Title of proceedings Nature Communications
DOI 10.1038/ncomms11539

Open Access

Abstract

Millennial-scale climate changes during the last glacial period and deglaciation were accompanied by rapid changes in atmospheric CO2 that remain unexplained. While the role of the Southern Ocean as a ’control valve’ on ocean–atmosphere CO2 exchange has been emphasized, the exact nature of this role, in particular the relative contributions of physical (for example, ocean dynamics and air–sea gas exchange) versus biological processes (for example, export productivity), remains poorly constrained. Here we combine reconstructions of bottom-water [O2], export production and 14C ventilation ages in the sub-Antarctic Atlantic, and show that atmospheric CO2 pulses during the last glacial- and deglacial periods were consistently accompanied by decreases in the biological export of carbon and increases in deep-ocean ventilation via southern-sourced water masses. These findings demonstrate how the Southern Ocean’s ’organic carbon pump’ has exerted a tight control on atmospheric CO2, and thus global climate, specifically via a synergy of both physical and biological processes.
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