130 



J. E. BRUGGER 



In the case of Chlorella in water swept with pure oxygen, we ob- 

 tained the curve shown in Fig. 3. Note that the steady state is similar 

 in intensity to that observed in pure nitrogen. Addition of small 

 amounts (short bursts) of carbon dioxide to the flowing gas tem- 



1 2 3 4 5 6 



IRRADIATION (MINUTES) 



Fig. 2. Time course of delayed luminescence during irradiation of Chlorella in 

 nutrient solution. 2% carbon dioxide in air atmosphere. 



16 



yl4 



5 12 

 o 



i 8 



6 

 4 

 2 







5 



UJ 



X 



o 



CHLORELLA 



t \ 



O2 - WATER 



H = "BURST" 0.2% CO2 



t \ 



3 4 5 6 



IRRADIATION (MINUTES) 



Fig. 3. Time course of delayed luminescence dming irradiation of Chlorella 

 in water. Oxygen atmosphere. Effect of transient addition of carbon dioxide. 



porarily reduced the chemiluminescence intensity, which then 

 quickly returned to its previous value. There was no change in pH 

 of the sohition due to the burst of carbon dioxide. The measurement 

 was made by adapting the sensitive pH meter of Professor Gaffron. 

 Something different was observed, as shown in Fig. 4, when a short 

 admixture of carbon dioxide was made when the streaming gas was 

 pure nitrogen. The luminescence was at first depressed but it later rose 



