Resumen de Influences of toxicants on freshwater biofilms and fish: from experimental approaches to statistical models
The main aims of this thesis are: i) to evaluate arsenic toxicity in two major, interacting components of the freshwater ecosystem, biofilm and fish, to provide information on environmentally realistic exposures and on biotic interactions, such as nutrient cycling that modulate toxicity; and ii) to rank predictors of toxicity to fish and quantify the differences in sensitivity among fish species. Our results highlight the interest and application of incorporating some of the complexity of natural systems in ecotoxicology and highlights that the current criterion continuous concentration for arsenic should be updated. We examined the factors that best predict toxicity in a set of widespread fishes using the random forest technique and assessed the importance of differential sensitivity among fish species using analyses of covariance. Our result indicates that caution should be exercised when extrapolating toxicological results since fish species differ in sensitivity and respond differently to different chemicals.
