SECT. 2] 



ORGANIC RECUSATION OF PHYTOPLANKTON FERTILITY 



175 



Table II — (cont.) 



"Acetic, formic, lactic, and glycolic (up to 1.4 mg/1.) acids are liberated from break- 

 down of larger organic molecules during the long extraction procedure (4-5 weeks). 



b 18 amino acids were found in the hydrolysates. The amounts and kind of amino acids 

 vary widely in samples. 



The data are few and limited. Aside from the "carbohydrates" estimation, 

 based on diverse localities and depths, the other data represent successful 

 extractions and identifications of the components of the dissolved organic 

 matter and are limited to a very few samples of sea-water. The JV-ethyl car- 

 bazole or anthrone methods are not strictly specific for carbohydrate. Never- 

 theless, this colorimetric reaction can be quantitated and serves to measure a 

 biologically active organic fraction which affects quantitatively the pumping 

 rate of oysters (Collier et al., 1950, 1953). This organic fraction may be of algal 

 origin ; the filtrate of cultures of several marine flagellates and diatoms contains 

 organic substances reacting with A T -ethyl carbazole (Collier, 1958 ; Guillard and 

 Wangersky, 1958). The oyster activity of such filtrates has not been reported. 

 Perhaps it may be possible to separate, and later analyze, the A-ethyl carbazole 

 reactive fraction from the organic solutes of sea-water extracted by co- 

 precipitation with Fe in alkali. 



3. Organic Products of Algae and Bacteria 



A . Excretion of Carbohydrates 

 Several fresh-water green algae, mostly Chlamydomonas species, liberate 

 soluble organic products in the culture medium. Six Chlamydomonas release as 



