8 



The Microflora: 

 Composition 9 Biomass, and 

 Environmental Relations 



F. L. Bunnell, O. K. Miller, 



P. W. Flanagan, and R. E. Benoit 



INTRODUCTION 



Tundra microflora show the same low species diversity evident 

 among the plants and herbivores. Two groups with broadly different dy- 

 namics dominate the microflora: rapidly changing bacterial populations 

 that typically degrade smaller molecular compounds and more slowly 

 changing fungal populations that are more capable of degrading larger 

 molecules. The accumulation of organic matter in tundra systems reflects 

 historical imbalances between production and decomposition. This chap- 

 ter presents an overview of the composition, abundance and diversity of 

 decomposer populations in the coastal tundra at Barrow as related to soil 

 characteristics previously described (Chapter 7). Activities of the micro- 

 flora are treated in Chapter 9. 



The overview presented is unavoidably influenced by the isolation 

 methods employed (Table 8-1). The usual cautions appropriate to inter- 

 pretations of microfloral isolations apply. Isolation techniques select 

 only a portion of the total viable flora. Microorganisms that grow readily 

 on artificial media and appear to be dominant may not be dominant in 

 their natural habitat. Similarly, fungi that fruit prolifically in the field 

 may not contribute the greatest biomass of active vegetative cells. There- 

 fore, the orientation of this discussion is broadly functional rather than 

 strictly taxonomic, particularly when bacterial groups are being dis- 

 cussed. The bacteria are examined as they contribute to transformations 

 of carbon, nitrogen and sulfur, whereas fungi are treated in more taxo- 

 nomic detail. 



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