Analysis of particulate organic matter fractions and organo-mineral associations using Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) in mangrove soils impacted by oil spills.

• Grant number: 25/11199-0
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: October 01, 2025
• End date: January 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Principal Investigator: Diego Barcellos
• Grantee: Juliana Sedmak de Souza
• Supervisor: Xose Lois Otero Perez
• Host Institution: Instituto de Ciências Ambientais, Químicas e Farmacêuticas (ICAQF). Universidade Federal de São Paulo (UNIFESP). Campus Diadema. Diadema , SP, Brazil
• Institution abroad: Universidade de Santiago de Compostela, Vida (USC), Spain
• Associated to the scholarship: 24/04610-2 - Carbon stocks and functional groups of soil organic matter in mangrove impacted by oil spill (Bertioga-SP), BP.IC

Abstract

Mangroves are important coastal ecosystems for global climate balance, mainly due to their high capacity to sequester and store organic carbon in soils. However, they are subject to natural and anthropogenic threats, such as oil spills, which can significantly compromise their ecological functions. One of the largest incidents recorded in Brazil occurred in 1983 in the Bertioga Channel (SP), when approximately 2,500 tons of oil were spilled, affecting large mangrove areas. In this context, the present project aims to analyze the impacts of this incident on the soil organic matter in mangroves impacted and not impacted by oil. To do this, two techniques will be employed, Fourier Transform Infrared Spectroscopy (FTIR), applied both to bulk samples and to fractions extracted by physical soil fractionation to obtain detailed information about chemical composition, and Thermogravimetric Analysis (TGA), applied to the fractions to evaluate the thermal stability of soil organic matter. Physical fractionation will allow differentiation between particulate organic carbon (POM: Particulate Organic Matter) and mineral-associated organic carbon (MAOM: Mineral Associated Organic Matter), which is more stable, thus contributing to the understanding of carbon stabilization processes in mangroves. Soil samples will be collected at different depths (0-5, 5-15, 15-30, 30-50, 50-100, 100-200 cm) in oil-impacted and non-impacted mangrove areas of the Bertioga Channel, aiming to identify changes in functional groups and thermal stability of mangrove soil organic matter. The combination of FTIR and TGA techniques will allow a detailed assessment of the quality and stability of organic matter, contributing to the understanding of the effects of anthropogenic impacts on soil carbon stocks in mangroves.