title: Fine sediment as environmental stressor affecting freshwater mussel behavior and ecosystem services.
abstract: Fine sediment pollution is considered a major stressor for aquatic ecosystems and their biodiversity. In particular, fine sediments have been suggested to play a crucial role in the declines of freshwater mussels which are considered keystone fauna of streams and rivers. Whereas the effects of deposited fine sediments on recruitment failure are well known, effects of suspended fine sediments on adult mussel behavior are less studied. Therefore the aim of this study was to investigate the effects of fine sediment exposure on freshwater mussel behavior and on mussel-dependent ecosystem services. Unio pictorum mussels were used to test three behavioral endpoints: Hall activity, transition frequency and relative water clearance rate. Mussels were exposed to fine sediments of different particle size classes (<45μm, 45-63μm, 63-125μm) and different concentration (0-10gL(-1)) of the smallest particle size class. Hall sensor technology and turbidity measurements were used to detect mussel behavior in presence of suspended sediments. Results revealed that mussels improve clearance of suspended particles out of the water column by 35%, independent of particle size class and concentration. Transition frequency was determined an unsuitable behavioral endpoint for non-soluble substances. Contrary to previous studies, we could demonstrate that fine sediments do not interfere with filtration by mussels and that mussels have a great influence on water purification, providing a valuable ecosystem service.
authors.affiliation: Aquatic Systems Biology Unit, Department of Ecology and Ecosystem Management, Technical University of Munich, Mühlenweg 22, D-85354 Freising, Germany.
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Lummer
authors.affiliation: Grassland Science, Department of Plant Science, Technical University of Munich, Alte Akademie 12, D-85354 Freising, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Auerswald
authors.affiliation: Aquatic Systems Biology Unit, Department of Ecology and Ecosystem Management, Technical University of Munich, Mühlenweg 22, D-85354 Freising, Germany. Electronic address: geist@wzw.tum.de.
authors.forename: Juergen
authors.initials: J
authors.lastname: Geist
mesh_terms: D000818:Animals; D017753:Ecosystem; D005247:Feeding Behavior; D005374:Filtration; D005618:Fresh Water; D019015:Geologic Sediments / Q000032:analysis*; D010316:Particle Size; D052638:Particulate Matter / Q000009:adverse effects*; D013312:Stress, Physiological; D049876:Unionidae / Q000502:physiology*
chemical_list: D052638:Particulate Matter
keywords: Clearance rate; Erosion; Filtration activity; Hall sensors; Invertebrate; Turbidity