By comparing the temperature structure (fig, 11) 

 with turbidity distribution (fig. 10), we see that the chang- 

 ing level of maximum turbidity lies just above the maximum 

 temperature gradient. Because the salinity gradients in this 

 area are negligible in the summer (less than 0. 004 parts 

 per thousand per foot), the temperature gradients correspond 

 to the density gradients. Thus, during this operation, the 

 greatest concentration of organisms tended to occur just 

 above the maximum density gradient. 



DISTRIBUTION OF MICROENTITIES IN RELATION TO 

 PHYSICAL FACTORS 



The two operations in 1961 were separated in time 

 by 2 weeks and were characterized by different physical 

 conditions and a corresponding difference in distributional 

 patterns of entities related to turbidity. Comparisons be- 

 tween distributional patterns of microentities, light trans- 

 mission, and temperature revealed some of the interrelation- 

 ships present in a marine environment. In the following 

 discussion, each microorganism is related to turbidity and 

 temperature for Operation I. 



28 



