Ocean Science

North Versus South

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Science  25 Apr 2008:
Vol. 320, Issue 5875, pp. 427
DOI: 10.1126/science.320.5875.427c

The Atlantic meridional overturning circulation (AMOC) transports shallow, warm water to the north and deeper, cold water to the south. The strength of this circulation, and in particular the amount of heat it transports northward, is thought to have a major influence on climate. Presently, much of the northward surface flow of the AMOC originates as nutrient-rich water from intermediate depths in the South Atlantic, and it has been suggested that those southern waters penetrated less into the north during past cold intervals when the AMOC was weaker. Came et al. present a record of the nutrient content of the northward flow of the AMOC over the past 23,000 years, preserved by benthic foraminifera in a sediment core recovered from near Florida, in order to determine how the contribution of southern water varied since the beginning of the last deglaciation. Their data allow them to document in more detail the changes in ocean circulation during the transition from glacial to interglacial conditions, and to illustrate how North Atlantic deep water formation, Antarctic intermediate water production, and North Atlantic climate were linked over that time period. — HJS

Paleoceanography 23, PA1217 (2008).

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