Fig. 8. Variation between 

 absolute (abscissa) and relative 

 (ordinate) values of biomass of 

 C alanus f inmarchicus s . 1 . in 

 the plankton of the Barents Sea 

 (Kamshilov et al . , 1958). 



ff 10 so wo /so 200 2S0 JOO JSO '/ffO 



mg/ni 



of 1975 in the neritic waters of the Barents Sea, the biomass, according 

 to our data, was about 3 g/m3 in the 0-50 m layer, over 99% of the biomass 

 being Calanus, with other crustaceans practically absent in the plankton. 



The remaining 

 C alanus in number, 

 others, damp the po 

 The flexibil ity of 

 increases when othe 

 maximum possible bi 

 real ization of the 

 trend in any pelagi 

 but in the latter i 

 species. Since abs 

 occur, it is clear 

 the pressure of the 

 even in Calanus, th 



members of the community, capable of exceeding the 

 though not in biomass, such as Oithona , Fritillaria and 

 ssible excursions of the biomass and of production, 

 the system, its stability in relationship to deformations, 

 r species are present, each of which fails to reach its 

 omass. The "price" of increased stability is incomplete 

 potential biomass and production, which is a general 

 c zone community, including the Arctic community, 

 t is particularly severe for opportunistic, subordinate 

 olute expulsion of "non- Calanus " zooplankton does not 

 that certain limiting factors are at work, increasing 

 environment on the dominant species. Consequently, 

 e reproductive potential is not fully realized. 



In the Arctic community, as in general in communities with nonrigid 

 hierarchic structure, the species following the dominant species in rank, 

 in case of a decrease in the number of the latter, takes its place. In 

 hydrologically unfavorable years, the total biomass remains at the median 

 level, but the relationship of the dominant groups, primarily in the 

 neritic zone, changes: In the White Sea, for example, the cladoceran 

 take first place in terms of biomass rather than the copepods; in the 

 estuarine Arctic plankton, the most numerous is at times Limnocalanus at 

 times Drepanopus , at times Senecel la or the Cladocera. 



The maxima in the Arctic plankton population curve may be numerous, 

 up to 7-8 in neritic waters (Fig. 9), with the curve of the annual course 

 of biomass having two, less frequently, three peaks. The course of the 

 curves of the dynamics of the populations of primarily carnivorous plankters 

 is more complex than that of primarily phytophagous plankters (Fig. 9A). 

 The smaller peaks of individual groups late in the year may merge (Fig. 98). 

 Variations of this type have been traced by many authors for the Barents 

 Sea (Manteyfel ' , 1939, 1941; Zelickman, Kamshilov, 1960), the Norwegian Sea 



59 



