Changes in ventilation and carbon storage at mid-depths of the equatorial Atlantic during the last glacial-interglacial cycle

• Grant number: 23/17460-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2024
• End date: February 28, 2025
• Field of knowledge: Interdisciplinary Subjects
• Principal Investigator: Cristiano Mazur Chiessi
• Grantee: Jaqueline Teixeira Alves
• Host Institution: Escola de Artes, Ciências e Humanidades (EACH). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 18/15123-4 - Past perspectives on tipping elements of the climate system: the Amazon Rainforest and the Atlantic Meridional Overturning Circulation (PPTEAM), AP.PFPMCG.JP2

Abstract

The Atlantic Meridional Overturning Circulation (AMOC) changes play an important role in the global carbon cycle. During millennial events (referred as Heinrich Stadials) that occurred in the last glacial-interglacial cycle, a reduction in ventilation and an increase in CO2 storage at mid-depths of the Atlantic occurred due to the weakening of the AMOC. These circulation changes, commonly reconstructed by the stable carbon isotope composition (d13C) in epibenthic foraminifera, indicate that rapid and negative excursions of d13C at mid-depths of the Atlantic were attributed to an increase in remineralized nutrients rich in 12C. Comparing different events of negative d13C excursions between reconstructions in the Atlantic may enable a comprehensive understanding of the magnitude of ventilation reduction and carbon accumulation at mid-depths. Despite the existence of mid-depths circulation records of the equatorial and South Atlantic based on d13C analyses, there is a notable scarcity of marine records with adequate temporal resolution to address all millennial-scale events of reduced ventilation during the last glacial-interglacial cycle. This project will address changes in the equatorial Atlantic mid-depth circulation over the last 150,000 years. To do so, temporal series of d13C from epibenthic foraminifera in marine cores collected in the equatorial Atlantic will be generated.