[Blooming and destruction of cyanobacteria in the drainage bassin of the hydrogen sulfide spring of Staraya Matsesty].

The growth of cyanobacteria belonging to the genera Oscillatoria and Anabaena (up to 2.1 x 10(7) filaments per 1 g of wet sample) was found in a water reservoir with a high content of sulfides (up to 9 mM) in Staraya Matsesta throughout the year. The spots of Oscillatoria are located in the spring in more illuminated areas as compared to Anabaena. In the spring, not only spots of actively growing cells were detected, but also accumulations of Oscillatoria cells being destroyed (blue spots). Water-bloom spots in which Oscillatoria prevailed can transform into the spots of Anabaena. The main accompanying forms in the spots of Anabaena are long thin filaments of the flexibacterial type while short rods are found in the spots where Oscillatoria predominates. Heterotrophic enteric bacteria (48 x 10(4) cells per 1 g), Bacillus, Pseudomonas, and coryneform bacteria were also detected. Green bacteria (Chlorobium) and nonsulfur purple bacteria (Rhodomicrobium) were present in small quantities (16 x 10(3) cells per 1 g) as well as sulfate-reducing bacteria (5--15 x 10(2) cells per 1 g) and thiobacilli (40--60 cells per 1 g). In the spring, stones were covered with pink spots of spherical motile purple bacteria and with yellow-green spots of filamentous green bacteria. The cyanobacteria from the spots are capable of oxygenated photosynthesis. Fixation of CO2 by them in situ is 0.08 mcg per 1 g of dry sample per hour or 0.06 mcg per 10(6) cells per hour, and is inhibited by 10(-5) M DCMU by 70%.