THE WHITE SEA 



183 



or end of May. Only at the shore does the ice form a continuous covering to 

 the water, the coast ice as it is called, which is sometimes several kilometres 

 wide. A continuous covering is also formed in the inlets and gubas and between 

 the islands, where the ice may be as much as a metre thick. The open parts of 

 the Sea are covered with floating ice of every kind. 



Currents 



The fresher surface waters of the White Sea flow out through the Gorlo into 

 the Barents Sea along its eastern shore (the 'Winter Shore'). Along the western 

 side (the Tersky Shore) more saline water flows into the Sea from the Barents 

 Sea, as may be clearly seen from the sketch (Fig. 77). 



Fig. 77. Distribution of salinity on the cross section through the 

 Gorlo of the White Sea along the line Sosnovetz Island to Megry 

 village (Timonov, 1950). 



Across the Gorlo (from Sosnovetz Island) very strong tidal streams in the 

 Voronka, and especially in the Gorlo, check the perpetual currents and create 

 a movement of the whole mass of water in the Gorlo first towards the Barents 

 Sea, and then towards the White Sea. While the speed of a permanent out- 

 flow current will hardly exceed 20 cm/sec, the speed of the tidal shift may 

 attain 7 to 8 km/h, or exceed 200 cm/sec. These streams and currents cause 

 the most violent, turbulent confusion of the whole column of water in the 

 Voronka and the Gorlo, and as a consequence their bed is covered with an 

 extremely hard sediment. 



As was shown by V. Shulejkin (1925), these tidal oscillations do not bring 

 the waters of the Barents Sea into the White Sea, but only shift the masses of 

 water in the Gorlo first in one direction and then in the other, for no more 

 than ten miles on one flood tide. An excellent illustration of this system of cur- 

 rents and streams (Fig. 79) is given by Derjugin (1928, from the data of M. Vir- 

 ketis) from the pattern of the distribution of certain plankton organisms. 

 V. Timonov (1947) presents the system of certain cyclonic and anticyclonic 

 rotations of the surface waters of the White Sea (Fig. 78). 



Calanus finmarchicus is not found in either the Voronka or the Gorlo, and 

 is abundantly represented in both the Barents and White Seas. The infusoria 

 Tintinnopsis campanula is carried into the Gorlo along with the outflow cur- 

 rent; contrariwise, the typical Barents Sea infusoria Cyttarocyllis denticulata 

 is carried along the Tersky shore into the White Sea. 



