Metabolic responses of the water flea (Daphnia magna) to individual contaminants and mixtures in presence of dissolved organic matter

Daphnia magna is a keystone organism found in freshwater environments and has long been used as a model organism in aquatic ecotoxicity studies. More recently, D. magna is emerging as a highly sensitive model for environmental metabolomics and biomonitoring programs. Commonly studied end points, such as median lethality and reproduction tests, tend not to be carried out at environmentally relevant concentrations. Nuclear magnetic resonance (NMR) spectroscopy has been regarded as a powerful tool for the study of complex biological and environmental matrices and has been used in metabolomic studies since the infancy of omic approaches. NMR-based metabolomics was employed to better understand how dissolved organic matter (DOM) alters the bioavailability and sublethal toxicity of individual contaminants and contaminant mixtures to the sentinel species D. magna .