1. Dept of Ecology and Ecosystem Modelling, Inst. of Biochemistry and Biology; Univ. of Potsdam; Maulbeerallee 2 DE-14469 Potsdam Germany
2. Faculty for Environmental Sciences, Inst. for Hydrobiology; Technische Univ. Dresden; Dresden Germany
3. Dept of River Ecology; Helmholtz Centre for Environmental Research (UFZ); Magdeburg Germany