Nature of Aquatic Environment 



Fig. 6. Diagram illustrating the distribution of temperature in Cayuga Lake 

 throughout the year. 



The yearly cycle — The general relation between sur- 

 face and bottom temperatures for the year are graphi- 

 cally shown in the accompanying diagram, wherein the 

 two periods of thermal stratification, ''direct'' in summer 

 when the warmer waters are uppermost, and "inverse" 

 m winter when the colder waters are uppermost, are 

 separated by two periods of complete circulation, when 

 all the waters of the lake are mixed at 4° C. The range 

 of temperatures from top to bottom is much greater in 

 the summer "stagnation period"; nevertheless there 



