Utilizando a geoquímica dos corais e bivalves para compreender as condições ambientais na Baía da Ilha Grande

Abstract

This doctoral thesis employs corals and bivalves as biological indicators to assess the impact of marine pollution by metals in Ilha Grande Bay (Rio de Janeiro, Brazil). The research utilizes a multidisciplinary approach, combining field surveys, laboratory experiments, and mass spectrometry techniques to provide data on the dynamics of metal pollution and its consequences for marine organisms in the region. Ilha Grande Bay is one of the most biodiverse areas in Brazil, and despite its ecological importance, the bay is under increasing anthropogenic pressure, with various sources of terrestrial and marine pollution that potentially impact marine habitats. In this work, a novel strategy is employed to investigate how metal pollution varies spatially and temporally in the marine environment, using coral skeletons and bivalve shells as proxies of marine pollution. The objective of this study is to evaluate metal contamination in Ilha Grande Bay. To achieve this, Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Laser Ablation Multi-Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) techniques are used to measure metal concentrations in coral skeletons (Tubastraea tagusensis) and bivalve shells (Perna perna). The work involves a combination of elemental and isotopic analysis of shells and skeletons to assess levels of metal pollution in the marine environment. The goal of this research is to evaluate the anthropogenic input of metals in the bay from the geochemistry of bivalve shells and coral skeletons to characterize changes in seawater chemistry that may have occurred throughout the animals' lives and have been recorded in the skeletal material. The results reveal significant variability in metal concentration among samples from different locations, indicating that the incorporation of metals in bivalve shells and coral skeletons is sensitive to the sampling location. Additionally, the variability of metal concentrations along the skeletons and shells suggests that environmental levels of metal contamination have changed over the animals' lifetimes as a result of anthropogenic input. The results of this research reveal that the levels of metals in Ilha Grande Bay are impacting marine organisms. It is hoped that this work will have implications for improving coastal management in the region by providing valuable information for decision-makers involved in the conservation of marine ecosystems in the region.