328 P. W. Flanagan and F. L. Bunnell 



lected at Meathop Wood in Great Britain. Utilizing these values they 

 found that the annual maintenance demands of the microbial biomass in 

 Meathop Wood were such that no organic matter would be available for 

 microbial growth, or for growth or maintenance of any other soil organ- 

 ism. In commenting on the obvious unreality of the situation, Gray and 

 Williams (1971) suggested a number of possible sources of error: 1) the 

 yield coefficient used was too small, 2) the estimate of maintenance re- 

 quirements was inflated, 3) microbial biomass was overestimated, and 4) 

 primary productivity was underestimated. 



In an analogous study, Flanagan and Bunnell (1976) attempted to 

 minimize the potential errors inherent in the biomass equation by incor- 

 porating laboratory determinations of the specific maintenance rates and 

 yield coefficients of major fungal species in the coastal tundra at Barrow. 

 Values for a and Y ' were calculated as 0.32 x 10"' g g"' hr"' and 0.35 g g"' 

 respectively from data on growth and respiration. The value of Y' ob- 

 tained by Flanagan and Bunnell (1976) is nearly identical to that calcu- 

 lated in studies of organisms from temperate regions, but the value of a is 

 only one-third of that calculated by Marr et al. (1963) in chemostat 

 studies and used by Babiuk and Paul (1970) and Gray and Williams 

 (1971). Using these coefficients Flanagan and Bunnell (1976) estimated 

 that the average standing crop of fungi in the standing dead grew, main- 

 tained and renewed itself at a cost of approximately 10 g substrate m"^ 

 yr"'. This estimate is compatible with the weight loss from standing dead 

 leaves calculated by converting carbon dioxide respired annually by mi- 

 crobes in the tissue to organic matter (Flanagan and Veum 1974). 



The following discussion is an attempt to 1) quantify the annual 

 maintenance demands of an average standing crop of microorganisms in 

 a unit area of Carex-Oncophorus meadow, 2) estimate the yearly poten- 

 tial for microbial production on the same area, and 3) examine whether 

 microbial potentials for substrate utilization during growth and mainten- 

 ance are compatible with estimates of the amount of organic matter pro- 

 duced and decomposed each year. 



Microbial Maintenance and Production 

 in the Coastal Tundra at Barrow 



Direct counts of bacteria from the soils are sparse. Calculations of 

 microbial utilization of substrate are constrained to estimates based pri- 

 marily upon biomass, maintenance demands and yield coefficients of 

 fungi. 



Utilizing the biomass equation and replacing x by 18.1 g m"^ (the 

 average standing crop of microbial biomass to 7 cm depth at the Carex- 

 Oncophorus meadow), a by 0.32 x 10"' g g"', and Y' by 0.35 g g"', calcu- 



