Freshwater bivalves with ecosystem engineering traits : The biodeposition rate of A. anatina and U. tumidus

Abstract: Freshwater bivalves of the family Unionidae have filter-feeding traits that alter freshwater ecosystems on several trophic levels. Filtration of organic and inorganic particulates in the water column transform matter through the mussel’s egestion before it is sequestered in the sediment, making it available as food for benthic invertebrates. Rates of filtration and deposition vary depending on species-specific traits, however, the filtration rate of Anodonta anatina (duck mussel) and Unio tumidus (swollen river mussel) are equivalent. This experimental aquarium study was performed by feeding duck mussel and swollen river mussel, to assess the biodeposition rate for both species. I hypothesized (1) that the biodeposition rate decreases for both species over a period of 180 minutes after feeding, and (2) there is no difference in deposited mass between A. anatina and U. tumidus. Results confirmed a decrease of organic and inorganic deposition over 180 minutes after feeding, with no significant difference of deposition mass between species. This study will contribute to valuable feeding methodology and knowledge for future studies of biodeposition of the family Unionidae.