2 

 The Barents Sea 



The Barents Sea is an open epicontinental fully saline body of water, mainly of 

 Arctic character, covered in its northern and eastern parts with floating ice 

 during the winter season. As the warm Atlantic waters flowing from the west 

 enter this sea they are cooled (from 8° to — 1-8° C) ; thus a complex system of 

 horizontal circulation is set up, consisting of several main cyclonic revolutions. 

 The Sea is well aerated. 



On the slopes of the shallows warmer and more mobile masses of Atlantic 

 waters meet cold and stagnant 'local' waters ; this causes strong vertical cir- 

 culations and other phenomena covered by the term polar front. In these 

 regions — where plant food is accumulated — the amount of benthos biomass 

 is 150 to 600 g/m 2 or more. In the regions of increased vertical circu- 

 lation, benthos biomass falls to 20 to 50 g/m 2 or less. This occurs in 

 the most westerly and especially in the northern part of the Sea, where 

 brown mud is widely distributed and owing to the insufficiently brisk vertical 

 circulation large amounts of carbon dioxide may accumulate in the bottom 

 layers. Marine fauna and flora with a preponderance of bivalve molluscs, 

 echinoderms, polychaetes, crustaceans, sponges, hydroides, bryozoans and 

 sipunculids are characteristic of this Sea. 



Bottom communities of the polymixed type belong, except for the littoral, 

 to the high and low Arctic sub-regions of the Arctic. The main mass of the 

 coastal vegetation is concentrated in the south of the Sea at zero depth, with 

 a biomass of up to 24 to 28 kg/m 2 (Laminaria, Ascophyllum, Fucus). At lower 

 levels the mass of macrophytes decreases greatly. The typical boreal littoral, 

 well represented in the warmer part of the Sea, disappears in regions which 

 remain under ice for a long time. 



As a rough calculation for the main groups the following ranges may be 

 taken as typical PI В coefficients:* for littoral and sublittoral vegetation 

 approximately 1 ; for zoobenthos about 0-25 to 0-2 ; for zooplankton approxi- 

 mately 1 ; for phytoplankton approximately 50 ; for fish on the average 

 not more than a sixth. The quantity of organic matter present on the sea 

 bottom is low and depends on its mechanical composition. In the north, 

 where soft bottoms predominate, there is 1 to 2 per cent carbon, 0T to 

 0-3 per cent nitrogen ; in the south (south of 72° N) there are 0-3 to 0-8 

 per cent carbon and 005 to 0T 5 per cent nitrogen. The C/'N ratio in the sea 

 bed is 5-5 to 80. 



The trawling industry both Soviet and foreign is highly developed in the 

 Barents Sea, the main catch being cod, haddock and bass. In that part of the 

 sea adjacent to the Murman coast herring fishing has been greatly developed 

 in Soviet times. 



* Ratio of annual production/average annual biomass. 

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