Main research questions:

1. How does structure and function of a natural periphyton changes during a chronic exposure towards herbicides and/or antibiotics (direct effects)?
2. Do we find any indirect effects towards grazer consuming contaminated biofilm? Do similar patterns appear regarding the direction of the effect in physiologically different grazers (Potamopyrgus antipodarum vs. Cloeon dipterum)?
3. Can these effects be counteracted by adaption of periphyton to those stressors?

In lotic ecosystems, biofilms or periphyton are important contributors to primary production. Additionally, they are a hot spot of biodiversity, composed of algae, diatoms, fungi and bacteria. Chemical contamination (eg. runoff or wastewater) poses a risk for biofilm quantity and quality. The research challenges of this PhD project are: understanding the impact of herbicides and antibiotics on primary producers’ diversity, the consequences for the food quality of the biofilm for higher trophic levels, and further bottom-up or top-down effects.