16 



The Bering Sea 



I. PHYSICAL GEOGRAPHY 



The Bering Sea is the largest marine basin of all the seas surrounding the 

 u.s.s.R. Its surface is 2,304,000 km 2 and its volume 3,683,000 km 3 . Its 

 greatest depth, in the region of Kamchatka Strait, is 4,420 m, its mean depth 

 1,598 m. The Bering Sea is divided by the 200 m isobath into two approxi- 

 mately equal parts : the northeastern shelf region, with depths of less than 

 200 m, and the southwestern part with depths of more than 3,500 m (Fig. 410) ; 

 this latter in its turn is subdivided by two trenches, a smaller, western one 

 and an eastern one, four times as big. The summits of Shirshov ridge rise to 

 depths of 1,000 to 2,000 m. It is a continuation of the Olyutorsky submarine 

 ridge. Another ridge stretching north of Semisopochny and Gorelov Islands, 

 part of the Aleutian arc, partitions off the southern part of the eastern basin. 

 The Bering Sea is enclosed on the south by the elevation of the Alaska Penin- 

 sula and the long Aleutian chain, composed of numerous islands and straits, 

 most of them shallow. 



Shirshov ridge does not reach the base of the Aleutian chain, for there is a 

 rather narrow, deep (3,500 m) strait between them connecting (less than 

 50 km) both parts of the hollow. The bathyal zone in the Bering Sea is com- 

 paratively small {Table 322). 



Table 322. Bottom topography of the Bering Sea (P. Ushakov, 1953) 



Area 

 Zone 



10 3 km 2 Percentage 



Shelf 1,000 44 



Bathyal 289 13 



Abyssal 992 43^ 



The Bering Sea is connected with the Pacific Ocean by the deep Kamchatka 

 Strait (4,420m). The trenches of the Strait are connected with each other, and 

 the western one with the Ocean, at all depths. A complete contact of sea and 

 ocean water masses and an identity of their water structure is secured by the 

 depth of certain of the Aleutian Straits. The Bering Sea can be considered as 

 an arm of the Pacific more than can any other sea. 



In the north the Bering Sea is connected with the Chukotsk Sea through the 

 Bering Strait. The latter is very shallow (not more than 40 m), and with a width 

 of 85 km its cross section is only 2-5 km 2 . 



With rare exceptions (in winter) the movement of water through the Bering 

 Strait is in one direction ; about 20,000 km 3 of Bering Sea waters enter the 

 Chukotsk Sea through it. 



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