Modeling 433 



each food source 5, is multiplied by its selectivity coefficient. For 

 example, let us consider the rate of ingestion of bacteria by 

 micrometazoans. Since these organisms also feed on algae and ciliates in 

 addition to bacteria, the total rate of ingestion is given by the following 

 functional relationship: 



RB208 =JV202^204 



where 



r (x3+x,o,+x.o.) -1 ^^ ^^^^ 



M.X 3 +X 10 1 +A: 20 1 + A; 206) J 



RB208 = total rate of ingestion by benthic micrometazoans 



of all food sources, 

 Xz = total algal biomass (surface and buried algal populations), 



Jfioi = bacterial biomass, 

 X201 =ciliate biomass, 

 X202 = micrometazoan biomass, 

 k 204 = specific V „ax for total ingestion of all food sources 



by micrometazoans at the reference temperature, and 

 k 206 = half-saturation constant for total ingestion of all food 



sources by micrometazoans. 



Then the rate of ingestion of bacteria by micrometazoans is 



RB211=RB208(xioi^22o)/(x3A:219+a:ioiA:22o+X2oiA:220 (15) 



where 



RB21 1 =rate of ingestion of bacteria by micrometazoans, 

 /C2i9 = selectivity coefficient for micrometazoan ingestion 



of algae (both surface and buried), 

 A: 220 = selectivity coefficient for micrometazoan ingestion of bacteria, 

 k22i = selectivity coefficient for micrometazoan ingestion 



of ciliates, and 

 X3, A:ioiandx2oi are defined as above. 



The loss of carbon from these species is a result of respiration, 

 egestion, and death (see Tables 10-2 and 10-3). 



Detritus and Dissolved Organic Carbon 



The two major inputs to the benthic detrital pool are death of living 

 organisms of the system and egestion from chironomids, ciliates, 

 flagellates, and micrometazoans. In addition, sedimentation of planktonic 

 detrital material contributes towards this pool. Detritus is ingested by 



