1. Eawag, Swiss Federal Institute of Aquatic Science and Technology; 8600 Dübendorf Switzerland
2. Aquatic Ecology Group; Department of Zoology; University of Cambridge; The David Attenborough Building, Pembroke Street Cambridge CB2 3QZ UK
3. Department F.-A. Forel for Environmental and Aquatic Sciences & Institute for Environmental Sciences; University of Geneva; Boulevard Carl-Vogt 66 1211 Geneva 4 Switzerland
4. School of Geosciences; University of Edinburgh; The King's Buildings Alexander Crum Brown Road Edinburgh EH9 3FF UK
5. Applied and Restoration Ecology Group; Pyrenean Institute of Ecology (IPE-CSIC); Avda. Monañana 1005 50059 Zaragoza Spain