portion of the Pacific Ocean, which is natural, considering the hydrologic 

 similarity of the two areas. The most important characteristic species 

 are Calanus cristatus , C^. plumchrus are replaced by C. glacial is and 

 Th. raschii . Certain cold-water species of the latter community descend 

 with the Anadyr Current to the south to Kamchatka and, together with the 

 neritic species, make up the western Bering-Sea neritic community, similar 

 in its specific composition to the eastern neritic community of this sea. 

 In Anadyr Bay and along the shores of Alaska, there is a neritic community, 

 characteristic of slightly less saline water. The primary species are 

 C entropages memurrichi , Acartia clausi , A. l ongiremis and, particularly, 

 Podon leukarti (up to 600 indiv./m-^ in the surface waters). 



At depths of over 200 m in the southern portion of the sea there is a 

 deep-water Bering Sea community--derivation of the boreal Pacific Ocean 

 deep-water community. 



The main abundant species of plankton in the Northern Pacific Ocean 



(C^. p lumchrus , £. bungii , Parathemisto japonica , Euphausia pacifica , 



Metridia pacifica beneath the thermocline and C. cristatus above it) form 

 concentrations with a wery high biomass--up to 2000 mg/m-^. 



After the spring rise of £. bungii , C. plumchrus , C_. cristatus , 

 Thysanoessa raschii and T. inermis to the surface, their biomass in the 

 0-100 m layer is up to 2500 mg/m^. 



The boreal waters of the northern Pacific as a whole are characterized 

 by a plankton biomass in the upper 100 meter layer on the order of 200-1000 

 mq/m3. In the south, these waters meet the warm waters of Kuroshio, in 

 which the biomass of plankton is 10-20 times less (Bogorov, Vinogradov, 

 1955). 



The Kuroshio waters contain a completely different plankton community, 

 including a significant quantity of tropical species. In the mixing area 

 between these waters and the boreal waters of the North Pacific, there is 

 an ecotone community, including both boreal and tropical areas in the 

 plankton. 



79 



