Changes in environmental conditions (temperature and [CO3 2-]) of the surface and intermediate waters of the southeastern Brazilian continental margin in the last two millennia based on the geochemical composition of foraminifera tests

• Grant number: 24/04249-8
• Support Opportunities: Scholarships in Brazil - Master
• Start date: December 01, 2024
• End date: November 30, 2026
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Geological Oceanography
• Principal Investigator: Renata Hanae Nagai
• Grantee: Julia dos Reis de França
• 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

Human activities since the Industrial Revolution have rapidly increased atmospheric carbon dioxide levels, causing surface ocean acidification and ocean warming. In the last decade, advancements in the development of ocean climate models have improved our ability to predict the impacts of climate change on the global ocean. However, the short period covered by direct observational records hinders our ability to determine the relative contributions of internal variability, natural forcing, and anthropogenic forcing to climate change. The Common Era, the last 2,000 years, plays a crucial role in understanding natural climate variations. Despite the importance of the Southwest Atlantic in inter-hemispheric heat transfer, there are currently no reconstructions of paleotemperature from this ocean basin in global Common Era databases. In this context, the aim of this research proposal is to reconstruct the paleotemperature and carbonate system conditions of the surface and intermediate waters of the southeastern Brazilian continental margin during the Common Era. To achieve this, data on Element/Ca ratio and isotopic composition in planktonic and benthic foraminifera tests from two marine sediment cores collected on the upper slope (861-1 and 2; 26°24.466'S, 45°38.855'W, depth: 1077 m) will be used to estimate variations in paleotemperature and carbonate system conditions of the study area's surface and intermediate waters. This research proposal is linked to the Thematic Project "The Santos Bifurcation: present and past - SANBIF" (FAPESP process 20/14356-5).