Fisheries Management Influence on Some Ecophysiological Groups of Bacteria in Lotic Ecosystems Of the Cefa Nature Park (Romania)

The nutrient circuit in aquatic ecosystems may seem simple, but the truth is that nutrient biochemical circuits are rather complex. Circuits are established by a series of interconnected biological, chemical and physical processes. Human activities lead to degradation of wet fields. Water quality and quantity have been changed, especially the quantity of polluting substances. Bacteriological studies in lotic ecosystems from Cefa Nature Park were carried out to establish four ecophysiologic microorganism groups: nitrogen-fixing bacteria, amonifying bacteria, nitrifying bacteria and denitrifying bacteria. Recorded values differ greatly from one species to the other according to sample points and season. Higher values in autumn are due to an increased intake of organic matter at the end of the vegetation period. Decomposition processes are intensified because of a growing number of microorganisms. Fishery management influences qualitative and quantitative variations in the microorganism communities of the lotic ecosystems in Cefa Natural Park.