1 S I — 



Phytoplankton 

 (mgChla/L) 



Nitrate 



(mgN/L) 



P0 4 

 (mgP/L) 



150 



06 



04t- 



02 



00 



08 



06 



04 



03 



01 



00 

 350 50 



Time (days) 



Herbivores 

 (mgC/L) 



L-u-i. 



i 1 1 r 



Organic- P 

 (mgP/L) 



Carnivores 

 (mgC/L) 



Figure 15. Plots of eight state variable trajectories (smooth curve) from Saginaw 

 Bay model. Model error estimates are represented as +1 standard deviation bands 

 (shaded) from first-order analysis. Data (circles with error bars) are represented 

 as baywide mean plus or minus standard deviation of all samples. From Scavia et. al, 

 (1981a). 



80 



