Productivity- and ocean circulation changes in the sub-Antarctic Atlantic during the last deglaciation and Marine Isotope Stage 3

• Main Authors: Gottschalk, Julia, Skinner, Luke C, Lippold, Jörg, Jaccard, Samuel L, Vogel, Hendrik, Frank, Norbert, Waelbroeck, Claire
• Format: Other/Unknown Material
• Language: English
• Published: PANGAEA 2015
• Subjects: Antarc*; Antarctic; Southern Ocean
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.845078; https://doi.org/10.1594/PANGAEA.845078

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.