CHARACTERISTICS OF PELAGIC AND BOTTOM LIFE 333 



scientists' attention is being focused more and more on living 

 organisms as one of the chief factors in the transfer and distribution 

 of radioactivity throughout the water masses. Ketchum and Bowen 

 (1958) write of "biological transport" and attempt to estimate 

 this quantitatively and to compare it with the "physical trans- 

 port." A term "biocirculation" has also been coined. It is evident 

 that this phenomenon cannot be overlooked either as a means of 

 transport or as an absorptive device. Most of the inert suspended 

 materials move comparatively slowly, and bacterial and phyto- 

 plankton cells provide a huge adsorptive surface (Table II; Fig. 6). 

 There is a considerable amount of material in suspension both 

 living (bacteria, phytoplankton, and zooplankton) and inert 

 (bioseston and abioseston). The quantitative determination of 

 these seston groups provided the possibility for an evaluation of 

 their part in adsorption and biocirculation (both vertically and 

 horizontally). 



Table II. Adsorptive Surface in V'arious Seston Groups in Distribution Zones 



of Middensity and Indices of Subsurface Biocirculation in a Column below 1 m- 



within Density Zones of Living Organisms 



The mechanism for chemical equilibrium within the water 

 masses is not well understood. Comparing data for the quantitative 

 distribution of organisms and their chemical composition (Vino- 

 gradov, 1953) with the chemical composition of the bottom 

 sediments, and with their accumulation rate indicated that it is 

 possible (at least for several chemical components) to make fairly 

 accurate formulas for the accumulation of certain substances on 

 the bottom and their return to the water masses. These estimates 

 can be obtained principally for CaCOa and SiOo. For example, the 



