724 



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



Fig. 350. Diagrammatic representation of quantitative dis- 

 tribution of (right) plankton and (left) benthos in the Ocean. 



from 1,000 to 0-4 g/m 2 with some further decrease in the depths of the Kuril- 

 Kamchatka trench. The curve of benthos biomass does not correspond to the 

 scale of depths given on the left. Bottom relief is represented by curve III. 

 Moreover, the decrease in the amount of plankton with depth for the trench 

 and for the ocean bed is also shown (I). 



The second, more abstract diagram (Fig. 350) gives the concentric zonation 

 character of the quantitative distribution of benthos with an amplitude of a 

 million, and the combined zonation (concentric on the periphery and along 

 the latitude) of the qualitative distribution of the surface plankton with an 

 amplitude of 20-50-100. 



A curious series of changes — an original abyssal growth to gigantic sizes — 

 has been established for certain groups of the deep-water fauna of the north- 

 western part of the Pacific Ocean. Birstein demonstrated this from several 

 species of mysids of the genus Amblyops {Table 296). 



There are some more similar examples, but the causes of this gigantism are 

 not yet clear. 



Some remarkable principles have come to light in the study of the vertical 

 distribution of animal organisms in the Ocean (Fig. 344). They must, however, 

 be further investigated and explained. These are the clearly discontinuous and 

 non-uniform changes in the faunal qualitative composition corresponding 

 with depth, a characteristic which is not repeated in its quantitative distri- 

 bution. The latter change proceeds, in general gradually and evenly, for both 

 plankton and benthos. 



Table 296. Depth of habitat and size of body of various species 

 of the genus Amblyops (Birstein, 1958) 



