THE BARENTS SEA 



137 



impeded. Thus in the main area of the Motovsky Bay and Kola Inlet the 

 biomass is 25 to 50 g/m 2 , whereas at their entrances it is 50 to 100 g/m 2 or 

 more. On average, as shown by M. Idelson (1934) for the whole benthos of the 

 Barents Sea the change of biomass is as follows : 



At depths of to 100 m 

 At depths of 100 to 200 m 

 At depths of 200 to 300 m 

 At depths of 300 to 400 m 



311 g/m 2 



168 g/m 2 



93 g/m 2 



48 g/m 2 



However, since as a rule any increase of depth is associated with a decrease 

 of food supplies and a progressive worsening of air conditions in the bottom 

 layer of water, it is difficult to say whether the fall of biomass can be explained 

 by the increase of depth alone. On the contrary it is possible to see from some 

 separate cross sections of the Barents Sea that the inverse dependence of the 

 change of biomass on depth is only partly valid. The degree of upwelling of 

 water is, as was pointed out above, a much more important factor in the dis- 

 tribution of the total benthos biomass. Moreover since in the Barents Sea the 



Fig. 52. Distribution of benthos biomass (g/m 2 ) in southwestern Barents Sea 



(Filatova, 1938). 



