Organic Matter Mineralization in the Littoral and open Lake Sediments of the Shallow Neusiedlersee, Österreich

Abstract

AbstractNeusiedlersee is a very shallow lake located in the eastern part of Austria. It is characterized by a reed belt that covers nearly 70% of its perimeter. Extended mixing and sediment resuspension due to wind action is observed in the open lake. Autochthonous seston and organic matter accumulates at the fringe and inside the reed belt. Space‐time fluctuations of bacterial populations in the open lake and littoral sediments and mineralization of organic matter in the littoral sediments were studied. Total number of bacteria was determined by epifluorescence. Ammonifying bacteria were determined by an MPN method. Experiments to evaluate organic matter mineralization were performed. Potential proteolysis and sulfate reduction were evaluated. Evidence of organic matter aggregation affecting the patchiness of bacterial populations in the sediments was found. Bacterial populations in the littoral sediments were more numerous and more active than those in the open‐lake sediments. Results suggest that the microbial community in Neusiedlersee littoral sediments play a key role in the carbon and energy flow for the whole lake.