446 J. L. Tiwari etal. 

 where 



RP201 = potential rate of ingestion of algae in the absence of 



another food type, 



y2oi =h'\omsiss of Daphnia, 



y 1 = biomass of algae, 



C201 = V„ai for ingestion of algae, 



C202 = half saturation constant for ingestion of algae, and 



Te = temperature effect 



The loss of biomass of the consumers is due to respiration and death 

 (RP221, RP223). It is also assumed that the loss of carbon due to egestion 

 is a constant fraction of the rates of ingestion of algae, bacteria and 

 detritus (RP204, RP209, RP219). A constant fraction of the dead 

 organisms is converted to U-DOC. 



Decomposers 



Bacteria are the only decomposers experimentally studied and are 

 included in the plankton model. Their growth rate is dependent upon the 

 concentration of U-DOC in the water. The rate of uptake of U-DOC by 

 these organisms follows a Michaelis-Menten type of equation (RPlOl). 

 They also grow on detrital particles and derive some U-DOC by 

 hydrolyzing these particles. The rate of hydrolysis is assumed to be 

 proportional to the biomasses of bacteria and detritus (RP102). 



The loss of bacterial carbon is due to respiration (RP107) and death 

 (RP103); a fraction of this loss is transferred to U-DOC. 



Detritus and Dissolved Organic Carbon 



Most of the detrital material in the water is planktonic in origin; 

 however, a small portion of it also comes from the bottom due to wind 

 resuspension. The death of algae, of bacteria, and of the consumers also 

 contributes to this component. The U-DOC comes from excretion from 

 both algae and vascular plants. A fraction of the planktonic detrital 

 material is also converted into U-DOC. 



