Response of littoral vs. profundal chironomid communities to multiple stressors in Swedish lakes: implications for ecological assessment (Master)

Using data from the Swedish Monitoring Program, the project will:

1. compare temporal patterns in taxonomic composition of chironomid communities in littoral and profundal zones;
2. provide insights into how climate change and nutrient enrichment impact on freshwater communities;
3. help to improve existing assessment strategies in Sweden.

Relevance and background

Aquatic ecosystems are facing tremendous changes due to a multitude of stressors, among which ongoing climate change and eutrophication are major large-scale drivers of change. Interactions among stressors can generate complex effects that fall below (i.e. antagonism) or exceed (i.e. synergism) the direct single effect of each stressor. Empirical evidence of the cumulative effects of multiple stressors on freshwater ecosystems is still limited, and little is known about their impacts on the ecological status of lakes. There is, however, growing evidence that shows that the concerted, synergistic action of climate change and eutrophication will contribute to the degradation of the structure of aquatic communities.

Furthermore, chironomid communities inhabiting different lake zones are expected to respond differently to natural environmental variation and anthropogenic  stressors. Among others, eutrophication is known to be more easily detectable in deeper lake zones, whereas other pressures (including climate change) are expected to have the strongest effect in the littoral zone. As a result, it is crucial to quantify the effects of multiple stressors on the spatial structure of chironomid communities at two depth zones (littoral and profundal) in Swedish lakes.

Project details

The project will analyze time series of monitoring data of chironomid communities in littoral and profundal zones, and other relevant environmental variables to provide insights into how multiple stressors influence the spatial structure of chironomid communities in lakes. Preliminary analyses have revealed a widespread shift in littoral chironomid communities occurring between 2000-2005, and further investigations will help to identify the underlying causes.

Expected results

You will be working in an aquatic ecology research group and learn to analyze multivariate time-series data using R. Results may be published in a high-ranked scientific journal (with you as a co-author).