90 



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



carbon content of the brown silts of the northern part of the Barents Sea 

 (T. Gorshkova, 1957). 



Clayey silt 

 Ooze 

 Sandy silt 

 Silty sand 



1 -78 per cent carbon 

 1-31 per cent carbon 

 0-97 per cent carbon 

 0-59 per cent carbon 



In other words, in regions with favourable conditions for deposition of the 

 fine-grained fraction, large amounts of detritus are also deposited, but on the 

 other hand these regions are usually unfavourable for the development of 



Fig. 30. Comparison of amounts of organic carbon 

 (/), fine sediment fraction (//), and benthos biomass 

 (///) in bottom soils of Barents Sea along cross sec- 

 tion from 75° 50' N latitude and 25° 00' E longitude 

 approximately along 74° parallel towards coast of 

 Novaya Zemlya. (IV) Depth, m (Gorshkova, 1958). 



bottom life. However, in the northern parts of the sea on soft brown sedi- 

 ments life is scarce and the amount of organic matter low. Finally, many 

 regions with sandy bottoms and a rich life may have a low content of organic 

 matter. Good vertical and horizontal water circulation prevents the accumula- 

 tion of organic matter on the bottom, sweeping it again and again into a 

 vortex. 



Hence, although on one hand one may accept the rule that seas rich in life 

 have more organic matter in their soils, in some of them a reverse relationship 

 between the amount of bottom life and of organic matter in the sea-bed may 

 be created. The comparison of benthos biomass and carbon content in the 

 sea-bed, given in Fig. 30, may serve as an illustration of this. The picture of 

 the relationship between the biomass density and the carbon content of the 

 sediment may also be obscured by the quantitative distribution of plankton 

 and its role in the formation of organic matter in the sea-bed. 



