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

Gottschalk, Julia and Skinner, Luke C. and Lippold, Jörg and Vogel, Hendrik and Frank, Norbert and Jaccard, Samuel L. and Waelbroeck, Claire (2016) Biological and physical controls in the Southern Ocean on past millennial-scale atmospheric CO2 changes. Nature Communications, 7. p. 11539. ISSN 2041-1723 DOI 10.1038/ncomms11539

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Official URL: http://doi.org/10.1038/ncomms11539

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.

Item Type: Article
Uncontrolled Keywords: 2016AREP; IA70
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
07 - Gold Open Access
Journal or Publication Title: Nature Communications
Volume: 7
Page Range: p. 11539
Identification Number: 10.1038/ncomms11539
Depositing User: Sarah Humbert
Date Deposited: 18 Apr 2017 21:04
Last Modified: 18 Apr 2017 21:04
URI: http://eprints.esc.cam.ac.uk/id/eprint/3938

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