The basic requirements for denitrification to occur in any marine, freshwater, or soil environment, regardless of climate are reduced O2 concentrations, a nitrogen source, and available carbon source.
Nitrate, the substrate for heterotrophic denitrification stimulates denitrification and large rates ofdenitrification are observed in agricultural soils, wastewater treatment farms, N polluted streams, estuaries, and forests. However, even when the supply of NO3 is not limiting, denitrification will only take place when the environmental conditions activate and stimulate the denitrifying population to switch from aerobic respiration to anaerobic respiration. If a soil is too dry or an aquatic system too aerated, microorganisms will not switch to denitrification. Furthermore, a lack in labile organic carbon or increased competition between heterotrophic bacteria for labile
Figure 1 This is a typical chamber to measure the fluxes of nitrous oxide from soil. The lid is closed for periods of 30-60 min, gas samples are collected from the chamber at the beginning and end of chamber closure through the sample port using a syringe. Samples are stored in vials or gas sample bags and are analyzed in the laboratory for nitrous oxide mostly by gas chromatography. Usually, information of the soil temperature, soil moisture, and soil mineral NO3 and NH4 are collected at the same time to provide a picture of the controlling variables.
carbon or competition with organisms that dissimilate nitrate to ammonium, will reduce denitrification.
Control of denitrification in terrestrial systems
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