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



the data obtained by S. Marshall and A. Orr (1955) and by A. Nicholls (1937) 

 for Calanusfinmarchicus, V. Bogorov (1939) calculated the volume of oxygen 

 consumed by the whole Eurytemora grimmi population and the carbon di- 

 oxide liberated by it in various layers of water in 24 hours. When it is dark the 

 main oxygen consumption takes place in the top layer (0 to 25 m) ; when light, 

 in the 50 to 83 m layer {Table 254). 



The coefficient of daily vertical distribution of the highest mass of plankton 

 can be calculated from these data. From the data of a definite station, col- 

 lected at a definite hour, it is possible to calculate the distribution of plankton 

 at any moment of the day, using the previously established coefficients of daily 

 vertical distribution of organisms according to stage and sex. 



For Eurytemora the coefficients of daily vertical distribution have been cal- 

 culated in the form given in Table 255. 



The converse picture is obtained for the day and night distribution of E. 

 grimmi. A similar method of calculation is less reliable when the stations are 

 not complete or only one sample was taken. 



Benthos 



Qualitative composition of phytobenthos. Kireeva and Shchapova's interesting 

 and comprehensive research on macrophytes (1939, 1957) should not be 

 omitted from the list of oceanographic work done in the Northern Caspian 

 in the last 15 years. A very full picture of their distribution in number and 

 species is given for the eastern and northeastern coast of the Sea. Before all 

 else the specific composition of the Caspian Sea macrophytes is characteristic, 

 as compared to the flora of other seas {Table 256). 



In the Mediterranean and Black Seas red algae predominate, then come the 



