Wind-Driven Upwelling in the Southern Ocean and the Deglacial Rise in Atmospheric CO2

Publication Type  Journal Article
Year of Publication  2009
Authors  Anderson, R. F.; Ali, S.; Bradtmiller, L. I.; Nielsen, S. H. H.; Fleisher, M. Q.; Anderson, B. E.; Burckle, L. H.
Journal Title  Science
Volume  323
Issue  5920
Pages  1443-1448
Journal Date  Mar 13
ISBN Number  0036-8075
Accession Number  ISI:000264101700031
Key Words  last glacial period; past 50,000 years; climate-change; late pleistocene; pacific sector; carbon-cycle; particle composition; tropical atlantic; north-atlantic; ice cores

Wind-driven upwelling in the ocean around Antarctica helps regulate the exchange of carbon dioxide (CO2) between the deep sea and the atmosphere, as well as the supply of dissolved silicon to the euphotic zone of the Southern Ocean. Diatom productivity south of the Antarctic Polar Front and the subsequent burial of biogenic opal in underlying sediments are limited by this silicon supply. We show that opal burial rates, and thus upwelling, were enhanced during the termination of the last ice age in each sector of the Southern Ocean. In the record with the greatest temporal resolution, we find evidence for two intervals of enhanced upwelling concurrent with the two intervals of rising atmospheric CO2 during deglaciation. These results directly link increased ventilation of deep water to the deglacial rise in atmospheric CO2.


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DOI  DOI 10.1126/science.1167441