482 



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



180 

 /60 

 /40- 

 120- 



loo- 

 se 

 60 

 40 

 20 



Benthos 6iomass 





IV 



v 



Fig. 227. Alterations in benthos communities of the Gulf of 

 Taganrog from west to east (Mordukhai-Boltovskoy with some 

 changes). 7 Cardium complex ; 7/ Ostracoda-Nereis community ; 

 /// Ostracoda community; IV Monodacna-Dreissena com- 

 munity; V Monodacna-Unionidae community; 1 Mediter- 

 ranean forms ; 2 Fresh-water forms ; 3 Relict forms. 



than that of the animal. The relationship of the two plankton groups and the 

 part played by separate phytoplankton components in different months is 

 shown in Figs. 228 and 229. In the Sea of Azov 188 species of phytoplankton 

 are known at present (see Table 198 by P. Usachev, 1927 and G. Pitzik, 1951). 



Table 198 



Group 



No. of species 



Percentage 



Peridineans 52 



Green algae and Heterocontae 48 

 Diatom 41 



Green-blue algae 35 



Flagellates 10 



Silico-flagellates 2 



Total 



1! 



27-7 

 25-5 

 21-8 

 18-6 

 5-3 

 11 



100 



