Characteristics of bacteriocenoses in the intestines of mollusks collected in different pollution zones

The aim of our work was to determine the disturbance of biocenoses of microorganisms in the digestive tract of hydrobionts from Lake Druksiai depending on pollution and to evaluate the role of microorganisms of the digestive tract of hydrobionts in self-purification processes of Lake Druksiai. Investigations on the composition of pollution -dependent biocenoses and functional activity of microorganisms of the digestive tract of 4 species of molluscs from Lake Druksiai were carried out. Microflora with a diverse qualitative composition (heterotrophic, proteolytic, amylolytic, hydrocarbondegrading and fecal coliform bacteria) was detected in the digestive tract of the molluscs under study. We have established that the quantitative composition of bacterial groups is the first to change because of unfavorable conditions. Fecal coliform and hydrocarbon-degrading bacteria which may constitute a threat to the macro organism were isolated. According to the abundance of bacteria in the digestive tract, Dreisena polymorpha and Anodonta cygnea can be considered to be the most suitable bio indicators. It is possible that these organisms accumulate the greatest amount of xenobiotics in their digestive tract; this is demonstrated by the abundance of fecal coliform and hydrocarbon-degrading bacteria in their intestines. (author)