TABLK 2 



Numbers (N, in 10" of individuals/m") and biomass 

 (B, in mg/m') of infusoria at Bering Sea stations (N/B). 



markedly lower than in the central portion of the Bering Sea. 

 As with the East Polygon, the predominant species were of the 

 genus Strombidium and ranged from 15-50 |im in size. 

 Throughout the gulf there were the large Strombidium strobilis. 

 the predatory Didinium sp., and Tintinnida ( Ptychocylis iinuda. 

 Pcmifavella denticulata). In contrast to the central sea, brackish- 

 water species ( Tintinuopsis sp. and Leprotintinnuspellucidum ) 

 were also present. The quantitative parameters maintained 

 high values throughout the gulf (Fig. 3). In the maximum- 

 concentration layer, the counts ranged from 6 to 

 75 X IO''individuals/ni\ The highest Ciliophora densities were 

 observed in the southern portion of gulf. The amount of 

 infusoria present declined considerably as one moved out of 

 this area. The biomass distribution, which ranged from 60 to 

 790 mg/m' in the layer of maximum concentration, followed 

 the same pattern (Fig. 3). Most of the infusoria were localized 

 in the top 30 m of the water column, with one or two maxima 

 either at the suiface or at a depth of 10-25 m (Fig. 2). 



Comparative analysis indicated that the infusoria distribution 

 closely matched chlorophyll levels. The most infusoria- 

 abundant stations (Stations 1 1, 13, 15, 19, 24, 27) were associated 

 with an area rich in chlorophyll and phosphates. Ammonia as 

 a by-product of microplankton metabolism was also plentiful. 

 The portion of the Bering Sea situated north of St. Lawrence 

 (Chirikov basin) is shallow with depth ranging from 27 to 49 m. 

 The hydrological setting is very intricate, since it is a zone 

 where three currents (water from the Gulf of Anadyr, Alaskan 

 Coastal water, and water from the Bering Sea Shelf) meet and 

 mingle. The Anadyr water is very salty and cold (temperature 

 ranging down to 2°C at Station 96). Greatly diluted by the 

 Yukon, the Alaskan Coastal waters are of low salinity and high 

 temperature (29.7 ppt and 1 1.2°C at Station 92). These waters 

 undergo only very slight mixing and flow into the Chukchi Sea 

 mostly intact. The flows in the eastern and western portions of 

 the strai t differ greatly in both biogenic element and chlorophyll 

 levels. The coastal waters of Alaska are many times poorer in 



157 



