1. Department of Aquatic Ecology; Eawag; Duebendorf 8600 Switzerland
2. Institute of Integrative Biology; ETH Zürich; Zürich 8092 Switzerland
3. Animal Ecology/Department of Ecology and Genetics; Evolutionary Biology Center; Uppsala University; Uppsala 75236 Sweden
4. Department of Environmental Toxicology; Eawag; Duebendorf 8600 Switzerland
5. Department of Environmental Systems Science; ETH Zürich; Zürich 8092 Switzerland