zooflagellate's ration was indicated. The calculation indicated that at a 

 dilution rate of D = 0.08 hrs" 1 in this case, a washing out of the zooflag- 

 e Hates from the reactor takes place (factually not observed), but at D = 

 0.06 hrs" 1 , the estimated calculated curve does not correspond to the 

 experimental one. 



When converting the dry weight of bacteria consumed into the number of 

 cells obtained we found that one zoof lagellate consumed 6.3 and 9.7 bacteria 

 per hour. 



Assuming that the coefficients of feeding and reproduction of the organ- 

 isms obtained in the experiments are close to those in nature, we can esti- 

 mate the degree of participation of bacteria, zooflagellates and infusoria 

 in the processes of destruction and transformation of organic matter in any 

 water body, e.g., in the Rybinskoye reservoir. In this water body the con- 

 centration of an easily degradable organic matter is on the average 10 

 mg/liter (Skopintsev, Bakulina, 1966); the biomass and the production of 

 bacteria biomass are 0.8 mg/liter and 0.6 mg/liter day (Sorokin, 1971); the 

 biomass of the zooflagellates is up to 0.02 mg/liter (Zhukov, 1973); and 

 the biomass of infusoria is about 1 mg/liter (Mamayeva, 1971). Using these 

 data and the calculated coefficients, we find that bacteria consume from 

 250 to 750 mg of DOM per day in a cubic meter. The growth in their dry 

 weight must make up from 100 to 250 mg/m 3 per day which quite corresponds 

 to the above mentioned value of the production of wet biomass. 



Infusoria consume about 360 mg/m 3 of the bacterial biomass per day, or 

 about a half their daily production. In one cubic meter, the zooflagel- 

 lates consume daily 4.8 mg of DOM and 1.3 mg of bacterial biomass, i.e., 

 they continue to feed in nature mostly on DOM, consuming only 0.2% of the 

 bacterial production as food. 



Thus, bacteria are the main consumer of organic matter in water bodies. 

 Zooflagellates cannot affect the rate of decomposition of organic matter by 

 predation on bacteria or by direct consumption of dissolved organic matter. 

 As for the infusoria, they can notably slow down the decomposition or or- 

 ganic matter by bacteria by means of reducing their number due to predation. 

 However, in water bodies, as a rule, a deficiency in nutrients has been ob- 

 served. Guaranteeing their recycling, infusoria may accelerate the bac- 

 terial destruction of organic matter. 



REFERENCES 



1. Bikbulatov, E.S., Skopintsev, B.A. 1974. Gidrokhimicheskiye 



materialy. No. 60, 23-28. 



2. Vinberg, G.G. 1949. Successes in Contemporary Biology. Uspekhi 



sovrem. biol. 28, No. 2(5), 226-245. 



3. Coryacheva, N.V. 1975. Transactions of the Inst. Biol. Inland Waters 



Ac. Sci. USSR, 23(26). Biology, Morphology and Classification of 

 Water Organisms. 



139 



