The dynamics of the Santos bifurcation during the last glacial maximum: exploring its relations to the Atlantic meridional circulation

• Grant number: 24/07120-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: October 01, 2024
• End date: June 30, 2028
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Geological Oceanography
• Principal Investigator: Renata Hanae Nagai
• Grantee: Ítalo Martins Paladino
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 20/14356-5 - The Santos Bifurcation: present and past, AP.TEM

Abstract

The Santos Bifurcation (BF) is a feature of the oceanic circulation of the Southwest Atlantic where the transport of Antarctic Intermediate Water (AIA) divides to the north and south. Recent studies suggest that changes in AIA transport over the last 25 thousand years have significantly impacted long-scale circulation, particularly associated with the Atlantic Meridional Overturning Circulation (AMOC). However, there is still no consensus on AMOC's relationship with AIA in this period; Nor is it known what role changes in the position and intensity of the BF have on the transport of the AIA to the north. Therefore, to better understand the relationship between these mechanisms, this project aims to reconstruct variations in the intensity and position of BF over the last 25 thousand years and evaluate their relationship with variations in AMOC and AIA transport, as well as potential associated factors of these changes. For this purpose, grain size proxies (classifiable silt and end members) and elementary ratios will be used in two marine cores, collected in the São Paulo Embayment. The results obtained helped to elucidate fundamental issues in understanding the BF patterns, and their relationship with the latitudinal distribution of the AIA and the AMOC. (AU)