US EPA

92805 

Book/Book Chapter 

Microbiological basis of NO and N2O production and consumption in soil 

Firestone, MK; Davidson, EA 

1989 

Wiley 

New York, NY 

Exchange of trace gases between terrestrial ecosystems and the atmosphere: report of the Dahlem workshop on exchange of trace gases between terrestrial ecosystems and the atmosphere 

47 

7-21 

WOS:A1989BU45V00002 

Regulation of trace N-gas production via nitrification and denitrification occurs at two levels: (a) control of the rates of these processes and (b) control of the relative proportions of end products. At the cellular level nitrification rates are controlled primarily by O2 and NH4+ availability. Similarly, denitrification is affected primarily by O2, NO3-, and organic-C availability. The availability of each of these cellular controllers is affected by numerous physical, chemical, and biological properties of the ecosystem, many of which have been characterized for a number of ecosystems. In contrast, the relationship between ecosystem properties and factors affecting relative proportions of end products is less well understood. Production of N2O by nitrifying bacteria results from reduction of NO2- when O2 is limiting, but the mechanism and factors affecting NO production during nitrification are not clear. Production of N2O via denitrification is affected by relative availabilities of electron donors (organic-C) and electron acceptors (N-oxides). Any factor that slows the overall rate of denitrification may also cause N2O to accumulate as a major end product. Production of NO via denitrification is more difficult to assess because control of cellular production and consumption is poorly understood. When NO diffusion is restricted by soil moisture, consumption by biological or abiological processes may be a dominant fate of this N-gas. Interaction of biological NO2- production and chemical NO2- decomposition (particularly in soil microsites) may also be an important source of NO. 

Andreae, M. O.; Schimel, D. S.