EN
Results of studies on a number of colony-forming units of heterotrophic bacteria, their physiological properties and nutritional requirements in water of Lake Jamno estuary are presented. The density of bacteria showed marked seasonal fluctuation with peaking in summer. Most numerous groups among bacteria studied were ammonifying, proteolytic and lipolytic strains. The smallest groups of them consisted of bacteria hydrolysing starch and reducing sulphates. In the water of Lake Jamno bacteria which for optimal growth required a mixture of amino acids (group A), vitamins (group G) and soil extract (group S) predominated. Bacteria having simple nutritional requirements were not numerous among isolated strains.