Ecotoxicological study of agrochemicals' effects on plankton community structure and function

Abstract

Currently, agrochemicals legal thresholds are mainly based on laboratory toxicity test to assess toxicant exposure effect based on single species test and single compound, However, two main shortcomings are associated with this approach: a) the extrapolation of the effect based on endpoint at individual levels into a complex ecosystem context with populations and communities, and b) chemicals do not occur alone in the environment, consequently mixtures should also be studied to better understand direct and indirect effect of agrochemicals inputs. Therefore, from this unexplored new scientific niche, this thesis explores scenarios of chemical mixtures, of ecological conditions and of theirs interactions. In order to contribute to a better understanding of agrochemical effects on the aquatic communities focusing on plankton and benthic communities of wetlands, this work encompasses two main scenarios: agrochemical scenarios (mixture, pulses frequency and limits) and ecological scenarios (ecological interactions: competition and hierarchical levels).