Research Article

The Southern Ocean's Role in Carbon Exchange During the Last Deglaciation

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Science  15 Dec 2011:
DOI: 10.1126/science.1208163


Changes in the upwelling and degassing of carbon from the Southern Ocean are one of the leading hypotheses for the cause of glacial-interglacial changes in atmospheric CO2. We present a 25,000-year-long Southern Ocean radiocarbon record reconstructed from deep-sea corals, which shows radiocarbon-depleted waters during the glacial period and through the early deglaciation. This depletion and associated deep stratification disappeared by ~ 14.6 ka (thousand years ago) consistent with the transfer of carbon from the deep ocean to the surface ocean and atmosphere via a Southern Ocean ventilation event. Given this evidence for carbon exchange in the Southern Ocean, we show that existing deep-ocean radiocarbon records from the glacial period are sufficiently depleted to explain the ~190‰ drop in atmospheric radiocarbon between ~17 and 14.5 ka.