Orbital-scale variability of heat content in the South Atlantic Subtropical Gyre: assessing seawater temperature via Mg/Ca analysis

• Grant number: 23/14028-6
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: February 08, 2024
• End date: February 07, 2025
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Cristiano Mazur Chiessi
• Grantee: Marcus Vinicius Lermen Kochhann
• Supervisor: Andre Bahr
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Heidelberg University, Germany
• Associated to the scholarship: 21/02877-3 - Paleoceanographic evolution of the South Atlantic subtropical gyre over the past 800,000 years based on a multi-proxy approach, BP.DR

Abstract

Terminations (i.e., transitions from glacial to interglacial periods) and interglacial periods are key intervals to understand climate dynamics under increasing and high atmospheric CO2 concentrations, such as Earth's present and future climates. Due to its intrinsic relationship with the Atlantic Meridional Overturning Circulation and its prominent role in controlling energy distribution and upper ocean buoyancy, the South Atlantic Subtropical Gyre (SASG) is a key, yet poorly understood, feature of the climate system. The analyses done in the home institution during the first part of the PhD project are already revealing promising data that will provide a significant improvement in understanding important features of the SASG. Nevertheless, an essential part of the foreseen results was planned to be carried out abroad once there are no laboratories with the needed analysis routinely available in Brazil. This research internship proposal aims to reconstruct the SASG northern boundary heat content variability, specifically within the thermocline, on orbital-scale over the last ~800,000 years based on magnesium to calcium ratio analysis. Analyses will be carried out at the Institute of Earth Sciences from Heidelberg University (Germany) on the deep-dwelling planktonic foraminiferal species Globorotalia truncatulinoides (dextral) collected from two marine sediment cores retrieved in the western South Atlantic, near the SASG northern boundary. (AU)