activity of the population of water and slime (fundamentally microorganisms) 

 is 658,000 ton C as organic matter. 



Of course, we know that the accuracy of the data depends on the analyti- 

 cal possibilities, and because of this we are inclined to examine such a 

 good agreement between the input and expenditure of organic mater as possi- 

 bly affected by some random element. Nevertheless, the main sources of 

 input and expenditure of organic matter in such a large and complex man-made 

 reservoir as the Rybinskiy reservoir are clear. 



Only a very small amount of matter and energy, in comparison with the 

 amount involved in the fundamental processes, flows through the rest of the 

 population of the reservoir. Taking into account the data from the biomass 

 and cycles of life of the different animals (Yu.I. Sorokin, see monograph 

 "Rybinskiy reservoir and its life," 1972), in the second trophic level 

 (herbivorous, detritous protozoa, rotatoria and Crustacea) nearly 20% of 

 the incoming organic matter is utilized. In the third trophic level (preda- 

 tor zooplankton, zoobenthos and fish larvae) only 0.2% is used and at least 

 as much for forage and predator fish. For man, it reaches only 0.05%. Of 

 course, it is necessary to remember that the last values expressed as ab- 

 solute units are fairly inexact because the calculation of such parameters 

 as species composition, zooplankton biomass and life cycles are only approx- 

 imated. So, as useful products on man's table, he receives only tenths or 

 hundreths of parts of the initial input of organic matter, and a large part 

 of it is utilized by bacteria. 



REFERENCES 



Belavskaya, A. P. and Kutova, T.N. 1966. The vegetation of the ephemeral 

 flood areas of the Rybinskiy reservoir. Publications of the Institute 

 for the Biology of Inland Waters, USSR Academy of Sciences. Vol 11(14) 

 Print "Nauka", M.-L. 



Hayes, F.R. and MacAulay, N.A. 1959. Lake water and sediment. V. Oxygen 

 consumed in water over sediment cores. Limnology and Oceanography, V. 

 4, N. 3. 



Kuznetsov, S.I. and Bezler, F.I. 1971. An experiment for determining the 

 balance of organic matter in the Rybinskiy reservoir. In: "Biology 

 and productivity of freshwater organisms". Publications of the Insti- 

 tute for the Biology of Inland Waters. USSR Academy of Sciences, Vol. 

 21(24). Print "Nauka", M.-L. 



Romanenko, V.I. 1964. Heterotrophic assimilation of CO2 by the bacterial 

 microflora of the water. Mikrobiologia XXXIII, Vol. 4. 



Romanenko, V.I. 1973a. Interrelation between the intensity of photosynthe- 

 sis of a population of algae uniformly distributed through the water 

 column and Secchi disc transparency. Information Bulletin of the Insti- 

 tute for the Biology of Inland Waters, USSR Academy of Sciences. No. 

 19. Print "Nauka", L. 



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