1. Department of Aquatic Ecology and Environmental Biology Institute for Water and Wetland Research, Radboud University Nijmegen, Faculty of Science Heyendaalseweg 135, 6525 AJ Nijmegen The Netherlands
2. Department of Coastal Systems NIOZ Royal Netherlands Institute for Sea Research PO Box 59, 1790 AB Den Burg (Texel) The Netherlands
3. Department of Estuarine & Delta Systems NIOZ Royal Netherlands Institute for Sea Research Korringaweg 7, 4401 NT Yerseke The Netherlands
4. The Fieldwork Company Van Schendelstraat 1, 9721 GV Groningen The Netherlands
5. Groningen Institute for Evolutionary Life Sciences (GELIFES) University of Groningen PO Box 11103, 9700 CC Groningen The Netherlands