Two centuries of sea surface temperature reconstruction in the western South Atlantic using shallow-water corals

• Grant number: 25/05223-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2025
• End date: May 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Geological Oceanography
• Principal Investigator: Leticia Maria Cavole
• Grantee: Giulia Anni Ferrazzano
• 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

Understanding the climatic dynamics in the western South Atlantic is crucial for anticipating future trends and assessing their socio-environmental impacts. Elements of the climate system, such as the Atlantic Meridional Overturning Circulation (AMOC), the Intertropical Convergence Zone (ITCZ), and the South Atlantic Convergence Zone (SACZ), play a crucial role in the distribution of heat and precipitation in Brazil. However, their interactions are still not fully understood. Furthermore, the scarcity of data prior to the satellite era makes it difficult to reconstruct long-term climate variations. This undergraduate research project aims to analyze the climatic variability of the last 200 years using isotopic data from the exoskeleton of a Siderastrea spp. coral colony, collected in Armação de Búzios, Rio de Janeiro. The study will investigate how the AMOC, ITCZ, and SACZ influenced regional climate over this period. The central hypothesis is that the isotopic composition of corals can provide a detailed record of past environmental conditions. To achieve this, the stable oxygen isotope composition (delta 18O) in the density bands of a coral core will be analyzed using isotope ratio mass spectrometry, allowing the reconstruction of seasonal and annual fluctuations in sea surface temperature. By providing new data on the climatic variability of the South Atlantic, this study will contribute to a more comprehensive understanding of the interactions between the oceanic and atmospheric systems, aiding in the construction of future scenarios and the improvement of climate models.