332 



THE DEEP SEA 



plankton organisms is not deriv^ed from coastal areas and that it 

 is not of primary importance. 



With depth the amount of the biomass also decreases (Fig. 5). 

 In various shallow- water areas and close inshore, the bottom- 

 dwelling fauna fluctuates one thousand times and on the ocean 

 bed only one hundred times. The plankton in the surface zone 

 fluctuates four hundred times, but only five to eight times in the 

 abyss. A thorough quantitative mapping of pelagic and of level- 

 bottom communities of the ocean is important in furthering 

 oceanographic knowledge. In ascertaining the regularity of the 

 distribution and replacements of living organisms as well as the 

 trophic relationships between them for a reliable estimate of the 

 populations in the halosphere, these may serve as an indication of 

 the physical processes and aid in our understanding of the role of 

 li\ing organisms in the chemical cycle in the ocean. All these 

 phenomena should be expressed ciuantitatively or they lose their 

 scientific or practical value. 



It is well known that in recent years oceanologists in all coun- 

 tries have paid considerable attention to the ways in which 

 radioactive fallout is distributed within the oceanic water masses 

 and also the speed by which it occurs. Simultaneously, the form, 

 rate, and scope of the oceanic contamination caused by radio- 

 activity is also being investigated. It is quite obvious that the 



1,000 



EZ3 Benthos 



Plankton 



Fig. 5. The change of fluctuation rate of the benthos and plankton biomass 

 with depth. 



