ANALYSIS OF THE PRESENCE AND EFFECTS OF PLASTIC POLLUTION ON AQUATIC ORGANISMS
Plastic pollution; Aquatic ecosystems; Microplastic; Fish health; Food security.
The increase in plastic production and consumption in recent decades has been accompanied by a proportional increase in its disposal and accumulation in the environment, especially in its potentially most polluting form, the microplastic (particles <5mm). The presence of this emerging contaminant in the environment leads to its interaction with organisms, which can generate multiple effects on ecosystem and human health. The scientific community has invested great efforts to better understand such effects. However, some aspects are still unclear, while others are under-explored, especially at broader ecological scales that involve ecosystem approaches and at several levels of biological organization simultaneously. Studies in this context offer necessary advances to broaden the understanding of this global threat. Therefore, this thesis is organized in three chapters that investigate the contamination by plastic in aquatic organisms, using fish as model organisms, and that evaluate the possible effects of this contamination in physiological, functional and ecological aspects. Additionally, we will address the issue of food security, related to human consumption of marine species potentially contaminated with microplastic. In the first chapter, we tested whether exposure to microplastic can affect the health and performance of freshwater fishes, evaluating biological factors from molecular to organismal level. In the second chapter, we tested, through an in-situ experiment, whether the presence of plastic in the environment influences the herbivory pressure of reef fishes, and consequently their ecosystem function. And in the third chapter, we seek to estimate the degree of contamination of commercially relevant species in RN in order to point out the ecological and socioeconomic impacts of plastic pollution. With this thesis, we hope to contribute to the construction of a broader and more solid base regarding the impacts of plastic and microplastic on aquatic organisms and ecosystems.