Berte M. Gebreyohanes Belay

Plastics have been widely used in everyday life since the 1950s, mainly because they are cheap and have a long durability. Plastics have a long degradation period, remaining in the environment for hundreds and thousands of years. During this period, plastics break down, due to photodegradation, abrasion, hydrolysis and biodegradation into smaller particles called microplastics (< 5 mm). Until now, much attention has been paid to quantify microplastics in the oceans. However, there are indications that microplastics are accumulating in the food web not only in the oceans, but also in fresh water systems.

Because microplastics shield the light, they can cause growth inhibition and decrease photosynthesis activity of freshwater microalgae species. In addition, zooplankton and benthic invertebrates accumulate microplastics in their digestive tracts leading to a reduced feeding activity, and in some cases reduced survival and fecundity. The zooplankton benthic invertebrates are in turn consumed by fish. In this way, microplastics can affect the entire food web, including higher trophic levels such as birds and humans.

The objective of this research project is to demonstrate the effect of microplastics on trophic interaction and scale up to food web effects in large indoor mesocosms. Linking small-scale laboratory studies to large-scale experiments and exploring more environmentally relevant scenarios will provide critical knowledge on the effects of microplastics at the community and ecological level, essential for further risk assessment.