Annelies Beuckels a,* , Erik Smolders b , Koenraad Muylaert a a KU Leuven Kulak, Laboratory Aquatic Biology, E. Sabbelaan 53, 8500 Kortrijk, Belgium b KU Leuven, Department of Soil and Water Management, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium