696 



BIOLOGY OF THE SEAS OF THE U.S.S.R. 



depths of 1 km and below the temperature remains practically constant 

 throughout the year. 



As is shown by the dynamic analysis of water masses (K. Bogoyavlensky 

 and V. Burkov, 1948) in the zone of the convergence of cold and warm waters 

 the currents lose their rectilinear course ; the main streams begin to meander 

 and several cyclonic and anticyclonic swirls are formed (Fig. 334). 



Even during the warmest season of the year the temperature of the water 

 in the Bering and Okhotsk Seas does not rise to any extent. The upper layer 

 is warmed only to temperatures of between 6° and 10°. In deeper layers 



Fig. 334. Chart of movements of surface waters within zone of contact of 



Kuroshio and Oyashio currents, May 1955. Vityaz voyage shown by a 



double line (Beklemishev and Burkov). 



there is a considerable difference between the Okhotsk and the Bering 

 Seas (P. Ushakov, 1953). The Sea of Okhotsk has a thick intermediate layer 

 with a temperature below freezing point throughout. In the Bering Sea the 

 intermediate cold layer is not so strongly developed ; its temperature is above 

 freezing point and it is concentrated mainly in Anadyr and Olyutorsky Bays. 

 Deeper down the temperature of the water is somewhat higher, up to 3° in 

 the Bering Sea and up to Г in the Sea of Okhotsk. 



As a result of the fall of temperature in the surface layers floating ice is 

 formed, thickest in the Sea of Okhotsk (Fig. 335) and thinnest in the north 

 and northeastern parts of the Sea of Japan. An intensive formation of ice 

 begins in the northern parts of the Bering and Okhotsk Seas as early as 

 December; it reaches its greatest development in March, when floating ice 

 covers all the Okhotsk Sea and the greater part of the Bering Sea. In the Sea 

 of Japan the ice may sometimes reach the Korean shores. Ice remains even 

 in June in the most northerly and westerly parts of the Sea of Okhotsk and 

 in the north of the Bering Sea, especially in the Bay of Anadyr. As late as May 



