Ji/'i? 



o.ceofOM! o.m s.i i.o /fi.s fpff aaar s.oi ^j ;.o ra.a tan 





i C.C! 



,.j.eio!o.m{}.m a.i u ifj wo h.dci o.ot at ;j fjsm 



li'D ,   r- — r^'" — : ^, i  ^— ^ ' 



10 



O.J 

 P. CI 



Fig. 7.' Energetic effectiveness of photosynthesis (Q,, abscissa) in 

 regions with varying levels of primary production at the surface (mg 



C/m-^-day): a, < 2; b, 2-10; c, > 10; d, regression lines for graphs a, 

 b, and c and for data on Q^ obtained during the 17th voyage of the 

 research vessel AKADEMIK KURCHATOV (17). Ordinate shows light depth (% 

 of penetrating radiation). 



possible, with the appearance of immersible monochromators (Morel, 1973; 



Smith, 1973; Pelevin, Kel ' bal ikhanov , 1974) 



measurements are not suitable for calculation of Q^ , 



coefficient Q,, i.e., the ratio of photosynthesis to 



of light by pigments, water and impurities (a), using the following 



equation : 



Since previous optical 

 ^■f" 1^^ we have calculated 

 total attenuation 



Ez(l-10-«) 



This coefficient Q^ was calculated for the 77 stations we have 

 mentioned (Fig. 7); its maximum value was found at the lower boundary 

 of the zone of photosynthesis. The effectiveness of photosynthesis here 

 averages 10%, at some stations--20%, near its limiting value. Closer to 

 the surface, Q, decreases in oligotrophic waters more strongly than in 

 mesotrophic and eutrophic ones. The main reason for this difference is 

 that in the oligotrophic regions, the water absorbs a greater fraction 



242 



