330 



THE DEEP SEA 



The Soviet oceanographers can hardly be charged with this 

 omission. In thirty-live years of marine investigations, the quanti- 

 tative method has been used in the study of the biomass, the 

 bacterial productivity, the marine plankton, and the animals and 

 plants of the benthos. Now Soviet investigators have collected 

 planktonic and benthic data for many years from several seas of 

 the USSR, especially in the Barents, Bering, Okhotsk, Azov, and 

 Caspian seas and constructed recent detailed charts for plankton 

 and benthos distribution in all the seas of the USSR. Thanks to 

 the work aboard the Vitjaz and Ob throughout the past decade, 

 quantitative data on the bacterial, plankton, and benthos distri- 

 bution in abyssal zones of the Pacific and Indian oceans and in 

 Antarctic waters at great depths and for bottom communities are 

 now available. The density of the benthos along the coast amounts 

 to a few kilograms, but on the ocean bed it drops to 100, then to 

 50, and finally to 10 mg/m^ (i.e., it is one-millionth that of the 

 coastal areas) (Fig. 3). 



Fig. 3. The quantitative benthos distribution in the northern Pacific and in 

 the eastern part of the Indian Ocean at depths exceeding 2000 m. Benthos biomass 

 measured in grams per square meter: 1, more than 1; 2, 0.1-1; 3, 0.05-0.1; 4, 

 0.01-0.05; 5, less than 0.01. 



