and Suctorida (Table 1). The polygon in question had 

 remarkably abundant infusoria (Fig. 1). In the layer of maximum 

 abundance their numbers ranged from 18 to 

 67 X 10* individuals/m' and biomass reached 1.2 g/m' 

 (Table 2). Station 2, with the least abundant infusoria, was 

 apparently situated in a strong current. The major portion of the 

 Ciliophora mass lay in the top 40 m of the water column, with 

 two density maxima — one at the surface, the other at a depth 

 of 10-20 m( Fig. 2). 



The South Polygon lay in the southernmost portion of the 

 Bering Sea, in the vicinity of Aleutian Islands straits, linking it 

 with the Pacific Ocean. The depths at its stations were on the 

 order of 4,000 m, the salinity about 33 %,,. High biogenic 

 component and chlorophyll levels were noted. The hydrological 

 setting was exceedingly complicated, as evidenced by major 

 differences in microplankton content at neighboring stations. 

 The Ciliophora species mix was similar to that of the East 

 Polygon, although some differences were noted. Thus, at 

 Station 1 10, the species typical of the region were joined by 

 Tintinnidium sp. and Cyclotrichium sp., while at the two 

 southernmost stations (111 and 112), near the straits, there 

 were some Steenstrupiella steenstrupii. Since this 

 characteristically Pacific species was seen nowhere else in the 

 Bering, it probably entered the sea through the straits. The 

 quantitative distribution of Ciliophora both here and in the East 

 Polygon was not uniform. Maximum abundance ranged from 

 1.9 - 36 X lO*" individuals/m' and biomass from 70 to 

 690 mg/m' (Table 3). Station 113, situated close to the central 

 Aleutian Islands, had the most abundant ciliates. Located near 



CHUKCHI 



PENINSULA 



Bering Sea 



109 .108 



.110 

 =^11 

 *• '112 



o o ^ 



t 



^ 



(3o O 



Fig. 1 . Infu.soria biomass in the layer of maximum abundance in the East and 

 South Polygons. ILegend:] Biomass in mg/m': 1) 1.220-460; 

 2)200-116;3)70-2.'5. 



TABLE 1 



List of dominant infusoria taxa 

 for the Bering Sea. 



Didinium gargantu Meun. 



Mesodiniiim rubra Lohm. 



Strombidium strobilis Wiiljf. 



Strombidium sp. 



Tontonia appendicularifonnis F-F. 



Tontonia sp. 



Leprotintinmts petlucidus { Cleve) Jorg. 



Codonellopsis tiirgescens K.a.C. 



Parafavella cylindirca (Jorg.) 



P. denticulata (Ehrb.) 



Pnchocylis iimula (C.a.L) Bdt. 



Canthariella brevis K.a.C. 



Buldir and Semichi Straits, Stations 1 10 and 1 12 had little 

 microplankton (see Frontispiece). Most of the infusoria mass 

 was localized in the top 40 m of the water column, with maxima 

 at the surface and subsurface layers and at the temperature 

 discontinuity depth of 10-25 m (Fig. 2). 



TheGulf of Anadyr portion of the Bering Sea is relatively 

 shallow, most ofit less than 100 m deep. The waters of the gulf 

 are a mixture of seawater and low-salinity Anadyr River 

 runoff. The biogenic component concentrations were high, but 



0. ,10 0, ,10 0^ 



,10 0, ,10 



^125 0, ,200 



70 



70 



0, ,10 0, , 7 0, , 7 0, , 7 



0. .450 Oi .360 0. .160 0. .300 



fTTt 



W 2' ^[32 ■ I 35 I 41 



0, ^300 



J 1100 0, ,170 



70 



50 



y 86 ' I 96 10 



0, ,5 0, ,3 0, 



0. .300 0, J 100 0. .1 



T ^ i 



Fig. 2. Vertical distribution of infusoria in the Benng and Chukchi Seas. 

 [Legend;] the ordinate axis is depth in m; the upper abscissas are 

 temperature in °C. the lower abscissas the biomass in mg/m'. Solid 

 curves describe temperature profiles. Numbers from 3 to 1 11 refer to 

 stations. 



156 



