• Aquatic ecotoxicology
• Stream ecology 
• Multiple stressors effect on heterotrophic biofilms in aquatic ecosystems

Major questions:

• Assess the impact of individual and combined stressors on heterotrophic biofilm structure and function under constant exposure scenarios using biofilms
   
• Assess the impact of relevant factor combinations on structure and function of the same biofilms simulating exposure scenarios for those stressors that are expected and documented in the field. These field relevant scenarios include, as an example, short term exposure to pesticides because of heavy precipitation leading to runoff from agricultural fields increasing at the same time the load of suspended solids and velocity.
   
• Assess whether the pattern identified in the laboratory can indeed be reflected in the field and explained by the data obtained in the laboratory.
   

The project aims to assess the effects of multiple stressors composed of pesticides, nutrients, temperature and suspended solids on heterotrophic biofilms under laboratory and field conditions. The methodology includes developing leaf associated microbial inoculum from selected stream site.  Then followed a full factorial experiment containing all selected factor combinations and their levels over 21 days, changing medium after every week. Various structural and functional parameters are being employed to quantify the effects of multiple stressors. Those variables include microbial decomposition of leaf material, fungal biomass, bacterial abundance, and for selected situations also metabarcoding.

Funding: DAAD, German Academic Exchange Service