Deepwater Variability During the Holocene


OCCI Project Funded: 2003

Proposed Research

Our goal is to generate several complementary lines of evidence that deepwater varied on centennial-millennial time scales in the Holocene and to document its regional effects. To do this, we will generate well-dated, detailed records of foraminiferal d18O and Mg/Ca to reconstruct temperature and salinity anomalies in surface, thermocline, and intermediate-depth sediment cores from the subpolar North Atlantic and the western tropical and subtropical Atlantic. Based on observational and modeling studies, we expect that reductions in North Atlantic Deep Water (NADW) will be expressed as positive temperature and salinity anomalies in tropical and subtropical cores shallower than ~1200 m. NADW variations will be expressed as nutrient anomalies (estimated from benthic foraminiferal d 13C and Cd/Ca) in deeper cores. Linking the deepwater records to surface temperature and salinity records from the subpolar North Atlantic will help us understand the mechanisms driving deepwater variability. Surface records from the lower latitudes will be used to evaluate the potential impact of deepwater variability on low-latitude climate.