TOTAL MICROORGANISMS: The concentration of total 

 microorganisms (fig. 28) ranged from 72 to 972 cells per 

 ml. In general, concentrations above 400 cells per ml 

 correlate positively with light attenuation. Doubts concern- 

 ing a cause-and-effect relationship, however, are raised 

 by a population greater than 400 cells per ml between 

 0200 and 1000 21 July at 48 feet. This concentration 

 occurred in water which showed 60-percent light trans- 

 mission and emphasizes the possible contribution of parti- 

 cles and dissolved substances not measured in this study. 

 Furthermore, Operation I demonstrated that cells must 

 be present in bloom quantities before they are major con- 

 tributors to turbidity. 



1000 1400 1800 2200 0200 



TIME (HOURS) 



0600 



1000 



Figure 28. Distribution of total microorganisms (organisms per ml), with transparency data (percent transmission) 

 in red, Operation II. 



47 



