TABLE 3 



List of dominant infusoria taxa 

 for the Chukchi Sea. 



Didinium sp. 



Mesodiniiim rubra Lohm. 



Cyclotrichium sp. 



Askenasia sp. 



Peritromus ovalis F-F 



Strombidium slrobilis Wulff 



Strombidium sp. 



Tonwnia appendicidarifonnis F-F. 



Tonlonia sp. 



Leprotiiuinmis pelhicidus (Cleve) Jorg. 



Tintinnopsis sp. 



Ptychocyiis sp. 



biomass was noted in the northern portion of the sea (Fig. 8), 

 with vertical distribution varying considerably from station to 

 station. The most frequent case was that of a single maximum, 

 either at the surface or at a depth of 5-10 m. Occasionally the 

 maximum number of ciliates occurred in the 15-25-m layer or 

 at the bottom (Fig. 2). In our view, the high biological 

 productivity of the Chukchi Sea is attributable largely to local 

 processes, because shelf waters are actively enriched by organic 

 matter through primary productivity in the presence of high 

 biogenic levels. 



Discussion and Conclusions 



Our study of ciliate protozoa in the Bering and Chukchi 

 Seas showed their development to be extremely intensive, 

 which places both seas among the most productive of the 

 world' s oceans. The ciliate distribution over the sea areas of the 



•69 



•68 



•67 



-66 



1 



ED- 



[z:-3 



Fig. 8. Biomass distribution (mg/nV) in the layer of maximum abundance at 

 Stations 45-74 in the Chukchi Sea. [Legend:] Biomass: \) 2330; 

 2)450-250:3) 198-85. 



Bering and Chukchi may be described as a mosaic that reflects 

 the heterogeneous character of their ecosystems. The principal 

 mass of infusoria with depth occurred in the top 40 m, with one 

 or two maxima. The species composition and quantitative 

 characteristics of the Bering Sea infusoria during the present 

 study (summer of 1988) were little different from those of 

 spring 1 98 1 , which seems to indicate that the marine ecosystems 

 in question had not experienced much deterioration as a result 

 of human pressure. It was discovered that the Chukchi Sea is 



TABLE 4 



Numbers (N, in millions of individuals/m') and biomass 

 (B, in mg/m- ) of infusoria for the Chukchi Sea (N/B). 



160 



