LARGE-SCALE CHLOKELLA CULTURE 



59 



TO CULTURE 



i: < 



LIGHT 



/';\---- 



NY 



PUMP 



FROM CULTURE 



PHOTO 

 TUBE 



AMPLIFIER 



SOLENOID VALVE 



S 



■^ 



TO CULTURE MEDIUM LINE 



Fig. 3 — Population density control, continuous culture process. 



Experiments have been made with the apparatus since July, 

 1949. Variations in water and micro-nutrients, mineral nutrients, 

 temperature, composition of aeration gas, population density of 

 culture, and other variables have been studied. 



To obtain information on growth in sunlight, a column 

 4-inches in diameter was constructed for operation out-of-doors. 

 This column is similar in construction and operation to the arti- 

 ficial light, continuous column. It is mounted on a pivot so that 

 the column may be operated normal to sunlight or in a vertical 

 position, or at any angle desired. A separate by-pass, fitted with a 



