80 BIOLOGY OF THE SEAS OF THE U.S.S.R. 



The amount of water flowing in and out through the above-mentioned 

 straits can change and create sometimes a positive, sometimes a negative 

 balance. Thus for July 1927 A. Sokolov gives the following data: 



Flowing into the Flowing out of 

 Barents Sea the Barents Sea 



North Cape-Bear Island 127-7 km 3 /day 97-6 km 3 /day 



Spitsbergen-Franz Joseph Land 38 68-3 



Franz Joseph Land-Novaya Zemlya 49-2 43-2 



Total 214-9 2091 



So we may accept that in one year 40 to 70 thousand cubic kilometres of 

 water flows into the Barents Sea from the southwest between the North Cape 

 and Bear Island, i.e. a little more than one-third of the water which, accord- 

 ing to Helland-Hansen's calculations, flows into the Norwegian Sea from the 

 south. Thirty-five to 60 thousand cubic kilometres flows out towards the 

 south from Bear Island back into the Norwegian Sea. At the north tip of 

 Novaya Zemlya 5 to 1 5 thousand cubic kilometres of water flows out of the 

 Barents Sea. According to Sokolov, the total volume of water flowing annually 

 into the Barents Sea is 75 thousand cubic kilometres, i.e. about a quarter of 

 the volume of the Sea. 



Vertical circulation and polar front 



Atlantic waters with a temperature of 4° to 12° and a salinity of 34-8 to 35-2% , 

 entering from the west, get gradually cooler as they move east and north, 

 and acquire the character of the local polar waters. Under the influence of the 

 floor contour, the Atlantic waters press against the shallows and, meeting the 

 local less saline and colder waters, are cooled and sink. Water from the depths 

 wells up in their place. Hence in precisely the same way as at the meeting point 

 of the warm saline Atlantic waters and the cold less saline East Greenland 

 waters in the Greenland Sea, the phenomena of intensified vertical circulation 

 occur in certain areas of the Barents Sea. As a whole these phenomena are 

 known as the polar front. It brings to the surface nutrient salts accumulated 

 in deep layers of the Sea and causes the ventilation of the bottom layers. As a 

 result the shallow Barents Sea is found to be very favourable for a 

 rich development of plankton and bottom life and for the feeding of a huge 

 amount of commercial fish (Fig. 23). 



Tides 



Widely open on the side of the Atlantic Ocean, the Barents Sea is greatly ex- 

 posed to the influence of tides. In the southern part of the Sea on the Murman 

 shores, the tidal range is more than 4 m, and when the tide goes out part of the 

 bottom populated by a very rich littoral fauna is laid bare. The tides become 

 weaker as we travel east and north (except for the eastern Murman coast 

 and the entrance to the White Sea) and are reduced to lm or less. 



