The role of the Atlantic Meridional Overturning Circulation in carbon accumulation at intermediate depths of the equatorial Atlantic during the Heinrich Stadial 1

Abstract

The global climate changes that occurred during the last glacial termination were accompanied by significant shifts in the Atlantic Meridional Overturning Circulation (AMOC). During the millennial-scale events of the last glacial termination, e.g., Heinrich Stadial 1 (HS1), CO2 accumulation at intermediate depths of the Atlantic was observed as a result of the weakening of the AMOC. These changes in circulation and the carbon cycle, commonly reconstructed through the stable carbon isotope (¿13C) composition in epibenthic foraminifera, show rapid and negative ¿13C excursions at intermediate depths of the Atlantic, which have been attributed to an increase in 12C concentration at these depths. Despite the existence of studies addressing circulation at intermediate depths in the equatorial and South Atlantic based on ¿13C analyses, there is a notable scarcity of marine records with sufficient temporal resolution to identify the internal structure of ¿13C records during the millennial event HS1. This project will investigate changes in circulation and carbon accumulation at intermediate depth in the Atlantic between ca. 29-14 thousand years ago, focusing on HS1. The time series of ¿13C in epibenthic foraminifera will be generated from a marine sediment core recovered in the equatorial Atlantic. The obtained results will be compared with other Atlantic paleocirculation records for a deeper understanding of changes in carbon accumulation at intermediate depths.