Climate-Floodplain Interactions in the Amazon Basin Revealed by Organic Geochemical Proxies

• Grant number: 25/09149-4
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: November 09, 2025
• End date: May 08, 2026
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Dailson José Bertassoli Junior
• Grantee: Dayane Batista Melo
• 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: 23/15362-7 - The distribution of seasonally flooded areas in lowland Amazonia during the Holocene, BP.DR

Abstract

Changes in Amazonian hydrology and vegetation have significant impacts on the global geochemical and hydrological cycles. In particular, the vast Amazon floodplains act as major sources of atmospheric methane (CH¿), meaning that changes in their extent can significantly affect the global CH4 budget. This internship proposal aims to analyze two marine sediment cores collected offshore the Amazon River to reconstruct the catchment-integrated climate and environmental changes of lowland Amazonia over the last 220,000 years, expanding past studies to the Middle Pleistocene. The proposed approach includes: (i) analyzing the isotopic composition (¿D and ¿13C) of molecular biomarkers to reconstruct changes in precipitation and vegetation of the Amazon Drainage Basin; and (ii) assessing the abundance and relative concentration of soil-sourced Bacteriohopanepolyols (BHPs), a proxy used to reconstruct variations in the extent of terrestrial wetlands. The results will contribute to refining the interpretations of the region's environmental evolution and its potential critical role in the global CH4 budget. (AU)