Pusch, M. M. Institute of Freshwater and Fish Ecology, +49 30 648407 10
Hoffmann, A. M. Institute of Freshwater and Fish Ecology, +49 30 648407 10
Fischer, H. H. Institute of Freshwater and Fish Ecology, +49 30 648407 10

 
ORGANIC CARBON RETENTION AND DEGRADATION BY UNIONID MUSSELS IN A LOWLAND RIVER (SPREE, GERMANY)
 
In the lowland river Spree (Germany), planktonic algae are retained in summer months by more than 90% on a 22 km section of the river, which is densely colonized by filter-feeding molluscs. In order to evaluate their role in the retention of seston, the rates of seston elimination and respiration were measured for three dominating taxa, the unionid freshwater mussels Anodonta anatina and Unio tumidus, and the prosobranch snail Viviparus viviparus. Measurements were made with simulated stream conditions, which influence filter-feeding rates. Individual mussels were able to filter up to 2 liters per hour. By this filtration activity, they account for most of the loss of suspended particulate organic matter (POM) in the river, which thus is transferred to the benthic zone. However, only a part of that material is metabolized and respired by the mollusks, indicating mainly microbial degradation of POM. System efficiency of POM retention was much lower in sections of R. Spree impacted by channelization, as mollusks prefer gravel and woody debris substrates which are reduced in these sections.
 
Day: Monday, Feb. 1
Time: 04:15 - 04:30pm
Location: Hilton of Santa Fe
 
Code: SS06MO0415H