Dimitri obtains his PhD in Applied Biological Sciences

We are happy to announce that our colleague, Dimitri van de Perre, on March 14, 2018, defended his dissertation to earn his doctoral degree! During his PhD, his research focused on estimating and predicting risks of multiple stressors on aquatic communities.

Congratulations, Dimitri! We wish you the best of luck in all your future endeavors, wherever these may take you!



Title of the doctoral dissertation: 
The combined and interactive effects of zinc, temperature and phosphorus on freshwater planktonic communities

Abstract of the doctoral research:
The main goal of the ecological risk assessment of chemicals (ERA) is the protection of populations and communities and the correct effect assessment of chemicals on the structure and functioning of aquatic ecosystems. At present, ERA is mainly based on data obtained from standard ecotoxicity experiments. These experiments are typically conducted under standardized optimal conditions, at the species level and exposed at a single stressor at the time. However, these general ERA approaches are in sharp contrast with natural conditions. Natural populations and communities are often exposed to a mixture of multiple stressors that are biotic (e.g. food shortage, predation) and abiotic (e.g. eutrophication, non-optimal temperature or water chemistry, metals). Species interactions such as predation and competition for food are two major biotic factors that are able to significantly affect the responses of organisms to toxicants. Additionally, abiotic factors such as temperature (T) can also play an important role affecting the toxic effects of chemical pollutants (e.g. by influencing its bioavailability and toxicokinetics). Therefore, by ignoring ecological interactions and by not considering natural field conditions these single-species tests oversimplify the actual field situation and ERA may not be protective. The aim of this PhD thesis was to investigate the combined effect of Zn with natural environmental stressors (temperature and/or phosphorous) at different organization levels (population vs. community) on freshwater organisms in order to increase the realism of current ERA.