Scott: Lakes of Tippecanoe Basin 15 



Table IV. Supersaturations 



L/ake 



JJeptn 



JJate 



Temper- 

 ature 

 centi- 

 grade 



Oxygen 



Satura- 

 tion 

 point 



x^er 

 cent 

 satura- 

 tion 



Cnapman. . . . 



Surrace 



Aug. Z, lo 



07 1 

 Zi . 1 



6 



72 



o . oy4 



1 on o 

 izU . Z 







X^in- O '10 



Aug. Z, 16 



OA 1 

 ZO . 1 



5 



82 



K Arro 



1 rvo A 

 1U2.D 



-\/T 



JManitou 



Surface 



A nrv 11 '1/1 



Aug. 11, l'± 



Zo . O 



6 



34 



FC ACkO 



1 1 a 

 llO . 4 







A iif^ 11 '1 /i 



Aug. 11, 14 



OA A 



5 



92 



K. dAQ 



O . O4o 



1 CiA Q 



Centeir 



Surface 



Aug. 19, '13 



26.1 



6 



52 



5.672 



114.7 



Center 



Surface 



Aug. 17, 12 



23 .3 



5 



93 



5.91 



100.3 





IM. 



Aug. 17, '12 



23.3 



6 



09 



5.91 



103.0 





3M. 



Aug. 17, '12 



22.5 



6 



09 



5.99 



101.6 



Pike 



Surface 



July 19, '13 



26.1 



6 



24 



5.672 



110.0 





2M. 



July 19, '13 



26.1 



6 



08 



5.672 



107.2 



Turkey 



4M. 



July 31, '13 



25. 



6 



33 



5.76 



109.0 



by photosynthesis just described, but is caused by the decay of 

 plankton in the upper layers. When plankton dies some of it 

 begins, at once, slowly to sink. Some of it, however, seems to 

 form gas bubbles which for a time float it. Disintegrating 

 Microcystis is often found near the surface. This decay of plank- 

 ton uses up oxygen, and in very calm weather it may be consumed 

 more rapidly than it is absorbed. The result is that the amount 

 present is often considerably below the saturation point. 



In the thermocline the oxygen always decreases rather rapidly. 

 This is due to the fact that the water in the upper part of the 

 thermocline has access to the wind-distributed oxygen of the 

 epilimnion, while the lower levels of the thermocline do not. 



In the deeper lakes, especially Tippecanoe and occasionall 

 in Eagle, there is a marked decrease in the amount of oxygen in 

 the upper part of the thermocline and an increase in the lower 

 part of the thermocline followed by the gradual decrease charac- 

 teristic of the hypolimnion. Juday has suggested that this phenom- 

 enon may be explained as follows: The plankton that dies in 

 the epilimnion sinks rapidly in the warm water of the upper levels. 

 But when it reaches the cooler and consequently more viscous 

 water of the thermocline, its rate of sinking is decreased, thus 

 making the planktonts more numerous, so numerous that, despite 

 the decrease in temperature, their decay diminishes the oxygen 

 more rapidly than in the epilimnion. 



