The Kara Sea 



I. GENERAL CHARACTERISTICS 



The Kara Sea (Fig. 93) is the first of the series of high Arctic epicontinental 

 seas lying along the northern shores of Siberia. With its western boundary at 

 Novaya Zemlya and its eastern limit at the western shores of the Taimyr 

 Peninsula and at the Severnaya Zemlya Archipelago, the Kara Sea is wide 

 open to the waters of the central part of the Arctic basin through the sound 

 between Franz Joseph Land and Severnaya Zemlya. Like other Siberian seas, 

 the Kara Sea loses much of its salinity, especially in its upper layer, from the 

 inflow of large rivers, and this leads to a fall in the salinity of the upper layer 

 throughout the Arctic basin. 



Favourable conditions for the penetration of fresh-water fauna, mainly 

 plankton and fish, into the southern parts of the Siberian seas are created by 

 their considerable dilution with river water. Abundant brackish areas at river 

 mouths and estuaries give shelter to a varied, most original fauna which, in its 

 aspect, is a high Arctic relict brackish-water fauna — a legacy of the Ice Age — 

 consisting mainly of fish and crustaceans. 



The Kara Sea may have been the centre of the evolution of this remarkable 

 fauna which penetrated, as a set of forms, far to the south into the depth of 

 Eurasia as far as the Caspian Sea and westward to the basin of the Baltic 

 Sea. 



Of all the Siberian seas the Kara Sea alone is exposed, in its western part, 

 to the influence of the warmer and more saline waters of the Barents Sea with 

 its characteristic flora and fauna. On the other hand, warmer and more saline 

 Atlantic waters, of the intermediate layer of the central part of the Arctic 

 basin, carrying a most original fauna rich in forms, penetrate from the north 

 through the troughs into the deeper layers of all the four seas, but principally 

 into the Kara Sea. The penetration of the boreal and abyssal fauna into the 

 Kara Sea from the north with the deep cold waters is also characteristic. 



The Siberian seas are paradoxical in their aspect owing to the above- 

 mentioned hydrological characteristics: in their northern parts the deep- 

 water layers of all of them are much warmer and have a qualitatively richer 

 fauna. The endemic marine fauna of all the four Siberian seas, except perhaps 

 the southern part of the Chukotsk Sea adjacent to the Bering Strait, has a 

 definitely high-Arctic aspect. 



The shallows off the shores of the Kara Sea differ greatly both in their 

 conditions and fauna from those of the deep central part. The first are well 

 aerated, better warmed, often considerably diluted, and populated by a 

 fauna rich in variety and at times in numbers. The second, characterized by 

 its low temperature and high salinity, has a thick brown mud floor and is 

 populated by a fauna poor both in its numbers and its variety. Its char- 

 acteristic features are a great preponderance of echinoderms, exceptionally 



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