Changes in precipitation over equatorial, tropical and subtropical South America under a collapsed Atlantic Meridional Overturning Circulation

• Grant number: 24/01641-4
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: April 30, 2024
• End date: April 29, 2025
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Cristiano Mazur Chiessi
• Grantee: Luiza dos Santos Amancio
• Supervisor: Enno Schefuß
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: University of Bremen, Germany
• Associated to the scholarship: 23/04804-9 - Changes in precipitation over equatorial, tropical and subtropical South America under a collapsed Atlantic meridional overturning circulation, BP.DR

Abstract

Precipitation is arguably one of the main controlling factors of life on Earth, changes in its patterns can lead to social disruption and massive economic loss. Recent findings point to a possible human-driven collapse of the Atlantic Meridional Overturning Circulation (AMOC). Knowing the effects of such a collapse is crucial for decision-makers to build an efficient adaptation strategy. The PhD project linked to this proposal aims to determine the consequences of AMOC's collapse over South American precipitation, a strongly debated and timely subject: while some pieces of evidence point to a widespread increase in tropical South American precipitation to the south of the equator during a collapsed circulation, others suggest that the increase is restricted to specific parts of the continent. Applying state-of-the-art proxies (i.e., hydrogen isotopes of leaf waxes, oxygen isotopes of surface seawater obtained via oxygen isotopes of foraminiferal carbonate) to a suite of marine sediment cores collected off eastern equatorial, tropical and subtropical South America, the region's precipitation changes over the past 20,000 years will be reconstructed, including the main two periods of weaker/collapsed AMOC. The research internship regards the execution of hydrogen isotopes (´D) analysis at the University of Bremen under the supervision of Dr. Enno Schefuß, a world-leading researcher on precipitation reconstruction using lipid biomarkers. Half of the marine sediment cores to be analyzed are stored in Germany: GeoB cores in the same institution of the internship and M78/1-235-1 at Heidelberg University. For the other half, M125 cores were sampled at Fluminense Federal University (Brazil), and a request to sample core CDH5 will be made to the Woods Hole Oceanographic Institution (USA).