The White Sea 



I. GENERAL CHARACTERISTICS 



The White Sea is a comparatively small Arctic body of water communicating 

 with the Barents Sea by a broad rather shallow channel. Compared with the 

 Barents Sea, the White Sea has a more continental climate — a warmer sum- 

 mer, and a harsher winter in which, for not less than half the year, the Sea is 

 covered along its shores by a broad continuous unmoving belt of ice, and out 

 at sea by floating ice-floes. 



A large inflow of river water and the restricted exchange of water with the 

 open sea are causes of the reduced salinity of the Sea and of the considerable 

 difference in salinity between the surface layer (25 to 40 m) and the deeper 

 masses of the water which in summer, in some areas, reach a salinity of almost 

 10% o (it is usually 4 to 5% ). 



In winter, when huge masses of ice form on the surface of the Sea, of which 

 a considerable part is carried out into the Barents Sea, and the surface layer 

 of water becomes brackish, there may set in a vertical homohalinity and an 

 intermingling of the whole column of water. In summer, when there is sharply 

 differentiated saline and thermal stratification in two layers, the phenomena 

 of stagnation and accumulation of carbon dioxide must take place in the deep 

 layer of the bathymetric part of the Sea. The poverty of the bottom fauna 

 and the predominance of brown mud point to this fact; however, so far there 

 is no experimental evidence in favour of this view. 



The instability of conditions of salinity, especially in the surface layer of 

 the White Sea, is characteristic also for different seasons of the year and for 

 different years. 



The flora and fauna of the White Sea, in consequence of its low salinity 

 and of the harshness of its winter, present, in the main, an impoverished 

 Barents Sea population, with weakly expressed endemic features and a certain 

 number of relicts, both warm-water and cold-water. 



The summer rise and winter fall in temperature, more considerable than 

 those in the Barents Sea, and the persistent low temperature in the bathymetric 

 part of the Sea cause a zoogeographic polarization of the Sea. In different parts 

 of it there exist simultaneously both warm- water and cold-water relicts, absent 

 from the adjacent parts of the Barents Sea. At the same time the White Sea is the 

 western limit of distribution of a series of Pacific Ocean forms. At great depths 

 high Arctic animal forms are predominant ; on the other hand low Arctic forms 

 are principally characteristic of the upper levels of the Sea (down to 30 or 40 m 

 and the littoral is inhabited by a north-boreal community of forms typical 

 also of the Murman coast and the shores of Norway and the North Sea. 



Not only in qualitative variety, but also by all indices of its biological pro- 

 ductivity, the White Sea falls considerably below the Barents Sea (biomass, 

 number of specimens, size, time of growth). 



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