175 



170 





Bering Sea 



65 



62 



61 



Fig. 3. 



Distribution of biocenoses in the Gulf of Anadyr and neighboring 

 waters. \-Macoma calcarea: 2-Nuculana lamellosa radiata; 3- 

 Pohchaem: 4-Echinarachnius parma: i-Halicbomiria panicea + 

 Balamis crenalus + Sirongylocenlnnus pallidus. 



180 



Fig. 4. Distribution of benthic biomass (g m -) at stations in the Gulf of 

 Anadyr and neighboring waters. 



only allow determination of three biocenoses (Fig. 5). The 

 region is dominated by 28 forms of benthic organisms (Table 

 1). Similar to the Gulf of Anadyr, there is also Macoma 

 calcarea biocenosis; it was found in two areas in both the north 

 and south areas of this region. The region was subdominated, 

 and sometimes even dominated alongside of Macoma, by other 

 ark shells (Yoldia amygdalae and Leioinicula inflata), 

 polychaetes (Nepthys caeca and Moldane sarsi). amphipods, 

 ceripedions(fia/fl/7/M(:re;;rt/«.v), and sponges. Maximum benthic 

 biomass of this biocenosis (found at Station 89) is smaller than 

 in the previous region and equals 649 g m -. North of 

 St. Lawrence Island, in the eastern part at the banks of the 

 Alaska coast and in the western area near the Soviet coast, we 



can clearly identify a biocenosis of sand dollars (Echinarachniiis 

 pamia). with average biomass of 2,358 g m - and an extremely 

 high maximum biomass of 4,378 g m- (Fig. 6). 



The entire region of the Bering Strait proper, from the 

 Chukchi Peninsula to Alaska, as well as a small area to the north 

 of St. Lawrence Island, at a depth of 44-50 m, is characterized 

 by pebble and gravel sediments with stones, sand, and shells. 

 This area is inhabited by fauna that is typical for this part of the 

 Pacific with solid and mixed sediments: sponges Halichondria 

 panicea; alcionariae Gersemia nibifonnis\ hedgehogs 

 Strongyloceutrotus pallidus; ceripedions Balamis crenatus; 

 and ascidiae Didendum sp. Benthic biomass in this biocenosis 

 reaches 780 g m'-. 



Chukchi Sea 



Bering Sea 



m^ 5 



Fig. 5. Distribution of biocenoses in the southeastern part of the Chukchi Sea 

 and northern part of the Bering Sea. I -Macoma calcarea: 2-Lewnucula 

 inflata: y Echinarachniiis parma:4-Haltchondriapanicea + Balamis 

 crenalus + Slronnylocentroliis pallidus: 5-Serripes groenlandicus. 



Southeastern Chukchi Sea 



Average benthic biomass of the region is 673 g m -. It is 

 dominated by 29 various benthic faunal forms (Table 1). 

 Differences in distribution of benthos in the eastern and western 

 parts of the region had been distinguished earlier by Grebmeier 

 et al. (1988) and were observed during the present expedition. 

 These differences are determined by peculiar features of waters 

 surrounding these regions. A more diverse western part of the 

 region has a most productive biocenosis (Macoma calcarea) at 

 a depth of 38-52 m on muddy and sandy sediments; average 

 biomass of this biocenosis is rather high and equals 979 g m - 



254 



