3. Production of Zooplankton . (E. A. Shushkina) 



Determinations of the rate of production of planktonic organisms 

 makes it possible to estimate the production of animals at various 

 trophic levels and the plankton community as a whole, and to approach a 

 determination of the regularities of functioning of pelagic ecosystems. 



Beginning early in the 20th century, studies of the production of 

 aquatic animals and their communities were developed throughout the 

 prewar years (Zenkevitch, 1931; Brotskaya, Zenkevitch, 1936; Winberg, 

 1936; Yashnov, 1940; Juday, 1940; and others). As a result of the study 

 of the biologic specifics of aquatic organisms of various trophic 

 levels, approximate estimates were produced of the specific rates of 

 their production (P/B coefficients). 



In the postwar years, interest in the problem of biological 

 productivity in aquatic environments increased still further, leading to 

 the accumulation of extensive factual material on the production 

 primarily of phyto- and bacterioplankton (Winberg, 1960; Strickland, 

 1960, 1971; Steemann Nielsen, 1960; Koblentz-Mishke et al . , 1970; 

 Sorokin, 1973e, g; and others). The studies of production of organisms 

 of upper trophic levels (zooplankton zoobenthos, fish) developed more 

 slowly (Zenkevitch, 1947; Greze, 1951; Elster, 1954; Shcherbakov, 1956; 

 Kamshilov, 1958, etc.). However, since the 1960's, the problem of 

 effective utilization of biologic resources of bodies of water became 

 more acute, leading to a rapid increase in the number of works on 

 estimation of the rate of production of aquatic animals, both at the 

 populations level (Mednikov, 1960; Konstantinova, 1961; Stross et al . , 

 1961; Greze, Baldina, 1964; Mull in. Brooks, 1970; Malovitskaya, 1971; 

 Greze et al . , 1971; Shushkina et al . , 1974), and for entire trophic 

 levels of zooplankton (Edmondson et al., 1962; Pechen', Shushkina, 1964; 

 Zaika, 1969; Mull in, 1969, Greze, 1970; Petipa et al . , 1970; V. D. 

 Fedorov et al., 1975). These materials, produced by more precise 

 methods than those used in the earlier years, based on a combination of 

 experimental and field studies, allow us to approach the estimation of 

 the intensity of the production of aquatic communities as an assemblage 

 of organisms at various trophic levels. 



In recent years, the number of studies of the production process at 

 the community level has rapidly increased (Raymont, 1966; Petipa, 1967a; 

 Petipa et al . , 1970; Parsons et al . , 1969; Winberg, 1973; Vinogradov et 

 al., 1973). One basic method used to perform the most important task of 

 modern hydrobiology--that of studying the regularities of functioning of 

 aquatic communities, predicting and, in the final analysis, controlling 

 their biologic productivity--is mathematical simulation of processes 

 defining the function of aquatic ecosystems. This method has been ever 

 more widely used in the past decade in the study of various problems 

 related to the growth and production of aquatic organisms (Bekman, 



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