[The number and respiratory intensity of bacterioplankton in the South Ural lakes].

The rate of oxygen assimilation by bacterioplankton was determined in the course of vegetative period in nine lakes of the Southern Urals. A correlation was established between the respiration rate and the presence of easily oxidizable organic substance in water within one lake. The optimum concentration of bacteria was found in the lakes when their activity was maximal. An increase or a decrease of this concentration results in a decrease of oxygen assimilation by a bacterial cell. The highest rate of oxygen assimilation by a bacterial cell was detected in mesotrophic lakes (2.0-10(-11) mgO/hr), being lower in oligotrophic and eutrophic lakes (0.9-10(-11)-1.0-10(-11) mgO/hr).