Toxicity and recover patterns of aquatic micro heterotrophic organisms exposed to metal contaminated food

Abstract

The increasing contamination of aquatic ecosystems motivates the study of interactions between metals and the biota. Metals are mainly released into the environment by industrial processes and poses risks to aquatic communities. Considering the importance of metals in the environmental contamination as well as the necessity of knowledge of the interaction of these elements with the aquatic organisms, the present study aims to evaluate the effect of metals (cadmium or copper) under the food activity, life history and secondary production freshwater microcrustaceans, like Ceriodaphnia silvestrii, by contaminating its food (the algae Selenastrum capricornutum exposed to metals). Aditionaly, it will be investigated the recover pattern of these organisms after the stress conditions, by introducing them in a new culture medium free of contamination. Food will be exposed to a total metal concentration of 5x10-8 a 10-5 M and the effect on the algal growth and its capacity to adsorve metal will be determined. Besides, we intend to investigate the influence of planktonic organisms on metal (cadmium or copper) dynamic and bioavailability aiming to contribute to aquatic ecosystems management and to the knowledge of some metal speciation, availability and interaction with aquatic organisms. (AU)