1. Centre for Ecological and Evolutionary Synthesis, Dept of Biosciences, Univ. of Oslo PO Box 1066 Blindern NO‐0316 Oslo Norway
2. School of Aquatic and Fishery Sciences, Univ. of Washington Seattle WA USA
3. Lake Ecosystems Group, Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg Lancaster Lancashire UK