Response of the deep tropical South Atlantic to changes in the Atlantic meridional overturning circulation: an isotopic approach

Abstract

The Atlantic Meridional Overturning Circulation (AMOC) plays a fundamental role in the oceanography and climate of the Atlantic realm. Atmosphere-ocean general circulation models have predicted a weakening in the AMOC strength for the coming decades. Conceptual and numerical models suggest that abrupt climate change in late Quaternary should produce marked changes in deep water mass geometry on the western South Atlantic. Nevertheless, the verification of this hypothesis wasn't possible so far due to the lack of adequate paleoceanographic records. Therefore, a comprehensive understanding of the response of the western South Atlantic to changes in AMOC is a key issue. Here, we will produce and use stable oxygen and carbon isotopic data from selected species of epibenthic foraminifera from a suite of three carefully selected sediment cores from the tropical western South Atlantic to: i) reconstruct the western tropical South Atlantic deep water mass geometry since the Marine Isotope Stage 3, and ii) verify the presence/absence of a relationship between deepwater mass geometry and changes in intensity of the AMOC on millennial timescales. (AU)