1. Workgroup Aquatic Chemical Ecology University of Cologne Biocentre Zülpichestrasse 47B 50674 Cologne Germany
2. Department of River Ecology Helmholtz Centre for Environmental Research (UFZ) Brückstrasse 3A 39114 Magdeburg Germany
3. Department of River Ecology & Department of Aquatic Ecosystem Analysis and Management Helmholtz Centre for Environmental Research (UFZ) Brückstrasse 3A 39114 Magdeburg Germany