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J. L. Tiwari et al. 



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240 



200 



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6 12 18 24 30 36 42 48 54 60 

 Time, days 



FIGURE 10-6. Field measurements (solid line) 

 and the model simulation (dashed line) of the 

 biomass of Daphnia in Pond B. 



Bacteria are the only decomposers included in the model (both 

 planktonic and benthic); the seasonal change in their biomass in the 

 plankton is shown in Figure 10-8. 



In general, the simulation shows the same seasonal pattern as the field 

 measurements. The actual values of the simulations are less important,as 

 we can raise or lower these by appropriate small changes in parameters or 

 even in initial conditions. Thus, the algal biomass is too high in the 

 simulation (Figure 10-4) but this can easily be corrected by some small 

 changes in the parameters of the photosynthesis and respiration. It would 



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c 

 v 



1400 e 



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1200 S 



s. 



-1000 



12 18 



800 



42 48 54 60 



24 30 36 

 Time, days 



FIGURE 10-7. Field measurements (solid line) and 

 the model simulation (dashed line) of the biomass of 

 chironomids in Pond B. 



