Radiocarbon evidence for alternating northern and southern sources of ventilation of the deep Atlantic carbon pool during the last deglaciation

Recent theories for glacial–interglacial climate transitions call on millennial climate perturbations that purged the deep sea of sequestered carbon dioxide via a “bipolar ventilation seesaw.” However, the viability of this hypothesis has been contested, and robust evidence in its support is lacking...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2014-04, Vol.111 (15), p.5480-5484
Main Authors: Skinner, Luke C., Waelbroeck, Claire, Scrivner, Adam E., Fallon, Stewart J.
Format: Article
Language:English
Subjects:
Antarctic Regions
Atlantic Ocean
Atmosphere - chemistry
Atmospheric circulation
Atmospherics
Carbon cycle
Carbon dioxide
Carbon Dioxide - analysis
Carbon Radioisotopes - analysis
Climate change
Continental interfaces, environment
Deep water
Geography
Glaciers
History, Ancient
Ice Cover
Ocean, Atmosphere
Oceans
Paleoclimatology
Physical Sciences
Radiocarbon
Radiocarbon dating
Sciences of the Universe
Seawater - chemistry
Telluric lines
Upwelling water
Ventilation systems
Water Movements
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Summary:Recent theories for glacial–interglacial climate transitions call on millennial climate perturbations that purged the deep sea of sequestered carbon dioxide via a “bipolar ventilation seesaw.” However, the viability of this hypothesis has been contested, and robust evidence in its support is lacking. Here we present a record of North Atlantic deep-water radiocarbon ventilation, which we compare with similar data from the Southern Ocean. A striking coherence in ventilation changes is found, with extremely high ventilation ages prevailing across the deep Atlantic during the last glacial period. The data also reveal two reversals in the ventilation gradient between the deep North Atlantic and Southern Ocean during Heinrich Stadial 1 and the Younger Dryas. These coincided with periods of sustained atmospheric CO ₂ rise and appear to have been driven by enhanced ocean–atmosphere exchange, primarily in the Southern Ocean. These results confirm the operation of a bipolar ventilation seesaw during deglaciation and underline the contribution of abrupt regional climate anomalies to longer-term global climate transitions.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1400668111