THE KARA SEA 



245 



A large number of original forms, characteristic of the warmer waters of the 

 northern Atlantic, immigrate from the great depths of the Arctic basin and 

 from the intermediate 'warm' layer of the Atlantic waters from the north 

 into the Kara Sea. 



At the same time a strongly marked phenomenon 'of the displacement of 

 zones' occurs in the Kara Sea. The bathypelagic fauna of the Arctic basin 

 penetrating the Kara Sea from the north through the deep troughs, and the 



Fig. 105. Alteration of habitat-level of members of the bottom fauna in 

 Kara Sea. / Barents Sea ; II Kara Sea ; /// Arctic basin and its slopes ; 

 I and 2 Main biocoenoses of the Barents Sea; 3 Echinoderm com- 

 munity; 4 Deep-water Atlantic fauna; 5 Abyssal fauna of the Arctic 

 basin (Filatova and Zenkevitch, 1957). 



Barents Sea fauna immigrating to the Kara Sea, rise to some levels unusual 

 for them (Fig. 105). This is often observed when passing from the oceans to the 

 seas fringing them, and from the seas into their bays. Portlandia arctica, 

 which lives at depths of 1 50 to 200 m in the Pechora trough of the Barents 

 Sea and in the White Sea, is frequently found at depths of 17 to 35 m in the 

 Kara Sea. Shell gravel horizon (Illrd group in the Barents Sea communities), 

 which occupies depths of 100 to 200 m and even 250 m of the Barents Sea, 

 rises to 20 to 100 m in the Kara Sea. The echinoderm community including 

 Ophiopleura and Trochostoma lives in the Barents Sea at a depth of 300 to 

 400 m and in the Kara Sea at 50 to 100 m. 

 It is interesting that certain bathyal and abyssal forms reach the Kara Sea 



