572 XI. HEMOGLOBIN CATABOLISM, I 



In addition to this phylogenetic adaptation an ontogenetic adap- 

 tation of one and the same species occurring at various depths of the 

 sea has been observed. Gaidukov added additional interest by the 

 discovery that some Cyanophyceae, for instance Oscillaria, on irradi- 

 ation with colored light took on a color complementary to that of 

 the light, adjusting their pigments so as to absorb the light more 

 fully (976). This theory of complementary chromatic adaptation has 

 been discussed by many workers {316,318,1126,1785,1978) and has 

 been confirmed. The mechanism of the adaptation is not yet clear. 

 According to Boresch (315,316) the color change is due to an altera- 

 tion of the ratio of phycocyanin to phycoerythrin, which are now 

 recognized as chromoproteins of two isomeric bile pigments (cf. 

 Chapter IV, Section 5.3.). It is not caused by a bleeching of the 

 absorbing chromoprotein, but on the contrary by its increased forma- 

 tion ("autosensitization"). 



Some of the algae (e.g., Ceramium rubrum) contain large amounts 

 of these chromoproteins (2%) and the absorption coefficients of the 

 latter are extraordinarily high, much higher than those of the pros- 

 thetic groups. The subject has been recently reviewed by Cook 

 U83) and Rabinowitch (2198, p. 418 ff.). 



