O 100 



FMAMJJASOND 



JFMAMJJASOND 



Figure 5. Seasonal dynamics of data and model output 

 for epilimnion (0-20 m) of Lake Ontario during 1972. 

 (a) Herbivorous copepods; (b) small cladocerans; (c) 

 large cladocerans; (d) omnivores. Symbols as in 

 Figure 4. From Scavia (1980a). 



-0.03 



- — Stratification - 



Gross Production 



I I I I I I L 



JFMAMJJASOND 



Stratification - 



Gross 



Production 



Figure 6. Rate plots indicating simulated 

 controls of epilimnion phytoplankton dynamics 

 in Lake Ontario during 1972. Large Others 

 represent nondiatoms greater than 20 um. 

 Top - Rates as d~l, bottom - rates as mg 

 C-L'-'-'d""- 1 -. Strippled area represents net 

 growth rate. From Scavia (1979). 



65 



