THE WHITE SEA 



185 



Temperature and salinity 



The vertical distribution of salinity and temperature in summertime in the 

 main basin of the White Sea is shown in Fig. 80. As may be seen, the tempera- 

 ture on the surface of the open sea at the warmest time of the year reaches 14° 

 to 16°. With depth the temperature falls quickly and at 35 to 44 m it already 

 equals zero. In the Dvina Gulf there is a dome-shaped rise of isotherms and 

 isohalines, and the 0° isotherm is found at a depth of only 12 m. Derjugin 

 suggests that this is the centre of the halistatic region formed by the circular 

 rotation of the waters, and calls it the 'cold pole' of the White Sea. Farther 

 down the temperature decreases still more, to —1-4° at approximately the 



Fig. 80. Vertical ranges of salinity and temperature in the White Sea at the beginning 

 of August 1922 on the cross section from Kandalaksha Bay to the Bay of Dvina 



(Derjugin, 1928). 



150 m level, and in places drops even to — 1-5°. Such clearly expressed strati- 

 fication is characteristic for salinity in summer as well. At the surface it is 

 equal to 25 to 26% and in the depths it reaches 30 to 34% . 



In winter the picture is sharply changed. A condition is established very close 

 to homothermic and the salinity of the surface layer rises considerably, as 

 may be seen from Table 78, borrowed from Derjugin. 



While in the open parts of the Sea (the Gulf of Kandalaksha) the summer 

 temperature reaches 15° (Fig. 81), along the shoreline far up the inlets and 

 bights this maximum is still higher and may exceed 20°. In this way the White 

 Sea, in consequence of its small size and of the depth of its extension into the 

 mainland, has much harsher winter climatic conditions than the Barents Sea. 

 On the other hand, opposite correlation is set up in summer, and the surface 

 layer of the White Sea, especially in the inlets, is much more strongly warmed 

 than that of the Barents Sea, and the deep layers maintain a very low tempera- 

 ture all the year round. 



This explains a series of biological phenomena. The depths of the Sea main- 

 tain a high Arctic fauna, while in the surface layer both Arctic and boreal 

 forms may exist. Some of them are absent either in the Barents Sea or in those 

 parts of pit adjacent to the White Sea. 



