As a trained Hydrobiologist Mechthild Schmitt-Jansen is a principal investigator of the Department of Bioanalytical Ecotoxicology at the Helmholtz Centre for Environmental Research – UFZ, and contributed to several national and international EU-funded projects on community ecotoxicology. Her research interests concern community responses to multiple stressors and contaminants with special focus on biofilm ecology. Her work is based on ecological concepts like stress-induced community tolerance. For understanding the underlying processes of stress responses, she investigates molecular responses like metabolomics and transcriptomics and links them to phenotypic observations including physiologically-based and ecologically-based parameters (dynamics of species traits, community tolerance). Model systems she is working with rang from algal cultures to periphyton communities, derived from complex field conditions as well as from model ecosystems.