28 



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



The relationships differed to a considerable degree in the Quaternary Period, 

 and even more during the Tertiary Period, not to mention the Mesozoic 

 era. 



The seas lying within the Soviet sector of the Arctic basin 



More than half of the coastline of the Arctic basin (North Polar Ocean) be- 

 longs to the Soviet Union. From the chart (Fig. 1a) it will be seen that a wide 

 belt of shallow water, 500 to 1 ,000 km in width, adjoins the coast of the u.s.s.r., 

 forming a system of separate, more or less open seas. Most of them could be 



Fig. 1a. Arctic basin bottom topography according to data from Soviet drifting 



observation stations. 



called inlets of the Arctic Ocean, rather than individual seas.* The most 

 westerly of them, the Barents Sea, is limited to the north by Spitsbergen and 

 Franz Joseph Land, and to the east by Novaya Zemlya. On the west the natural 

 boundary of the Barents Sea is formed by the edge of the continental shelf at a 

 depth of 500 m. To the south the White Sea adjoins the Barents Sea. The Kara 

 Sea extends from Novaya Zemlya to the Severnaya Zemlya archipelago, and 

 between the Severnaya Zemlya and the Novosibirsk Islands lies the Laptev 

 Sea. Beyond as far as Wrangel Island there is the East Siberian Sea, and lastly 

 the Chukotsk Sea lies between Wrangel Island and the Bering Strait. All these 

 seas, except for the western half of the Barents Sea, and part of the Chukotsk 

 Sea adjoining America, lie within the boundaries of the u.s.s.r. Whereas the 

 eastern and western boundaries of these seas can be defined fairly accurately, 



* The epicontinental bodies of water composing the Arctic Ocean form about 37 per 

 cent of its whole area, whereas the continental self of the world-ocean forms only 8 per 

 cent of its area. 



