GENERAL CHARACTERISTICS OF THE NORTHERN SEAS 63 



Table 26 



No. of species, except 

 Endemic forms of Arctic Ocean Foraminifera 



Deep-water species : 



Purely abyssal 24 



Abyssal eurybathic 32 



Bathyal 5 



Shallow eurybathic 7 



More widely propagated species 



Deep-water species : 



Purely abyssal 3 



Abyssal eurybathic 8 



Bathyal 



Shallow- water eurybathic 15 



Total 94 



species and even endemic genera, the abyssal fauna of the Arctic Ocean is 

 ancient, going back at least to Tertiary genesis. 



On the other hand, E. F. Gurjanova (1938) thinks that all this fauna ori- 

 ginated from the forms inhabiting the shallow zones of the Arctic in the post- 

 glacial period. This fauna consists partly of the same species which still live 

 in the shallows, and partly of species developed from these latter. On the basis 

 of her data Gurjanova considers the Arctic basin as very young,* but this is 

 difficult to accept. If the deep-water fauna did exist here during preglacial 

 times, it might have perished totally or partially during the Ice Age as a result 

 of a considerable loss of salinity of the surface layers of the sea or perhaps 

 throughout the whole basin as occurred in the Sea of Japan. 



As regards the pelagic fauna of the Arctic basin V. Jashnov (1940) has also 

 come to the conclusion that specific abyssal pelagic fauna of the Arctic basin 

 does not exist. Of the 46 species of Copepoda found in the depths of the Arctic 

 basin, the Norwegian and Greenland Seas and Baffin Bay, 42 are known also 

 in the rest of the Atlantic. The same may be said about the coastal vegetation 

 (macrophytes) of the Arctic basin. It has no peculiar features, it is simply an 

 impoverished Atlantic flora. 



A remarkable phenomenon was observed by the latest Soviet high-latitude 

 expeditions — many members of the abyssal fauna of the Arctic basin have 

 risen into the comparatively shallow zones along its fringes in seas with high 

 Arctic conditions. This is particularly evident in the northern part of the Kara 

 Sea and the northwestern part of the Laptev Sea, where great depths approach 

 closely and where there are trenches (200 to 400 m) running from them. 



* It must, however, be borne in mind that the abyssal fauna of the central part of the 

 Arctic Ocean is as yet practically uninvestigated. So far explorers have only penetrated 

 along the continental slopes of the northern part of the Kara Sea and the Novosibirsk 

 shallows. 



