Decomposers, Bacteria, and Microbenthos 347 



0.8 



- 0.6 



« 



2 0.4 



« 

 u 



o 



c 



;o.2 



o 



1210 1610 2010 2410 0410 



Time, hrs 



0810 



1210 



4 6 8 



Temperature, °C 



10 



FIGURE 8-3. a) V^^^/or acetate uptake, 19 to 20 August 

 1972, in the water of Pond B-6. b) Relationships between 

 ^ max ^'^^ temperatures (same dates as above). 



ponds. Correction of the Vn,ax values to a standard temperature did not 

 improve the correlation. 



Variation in the heterotrophic activity of plankton from pond to pond 

 was also considered in an experiment on 9 August 1973. This comparison 

 utilized the uptake of labeled acetate and glucose at only one 

 concentration (192 and 2.1 Mg C liter ', respectively). This method 

 (Parsons and Strickland 1962) allows calculation of velocity of uptake, v, 

 at that substrate concentration and of turnover time, T,, but not V„ax or 

 {K,->rSn). A transect of 25 ponds yielded glucose uptake velocities of 0.07 

 to 3.10 MgC liter ' hr ', with a mean of 0.514 ^g C liter ' hr '. Results 

 for acetate were similar, with a range of 0.04 to 1 .5 1 Mg C liter ' hr ' and 



