Wrage et al. 2004

Wrage N, Lauf J, del Prado A, Pinto M, Pietrzak S, Yamulki S, Oenema O, Gebauer G. 2004. Distinguishing sources of N2O in European grasslands by stable isotope analysis. Rapid Communications in Mass Spectrometry 18: 1201-1207.

These authors used the signature ratios of stable isotopes of oxygen and nitrogen in a range of soil chemicals and microbial metabolic pathways to identify the source of N2O produced in grasslands monitored as part of a long-term greenhouse gas international experiment. There are 3 known pathways to N2O production: nitrification, in which N2O is produced as a by-product of ammonium oxidation to nitrate, nitrifier denitrification, in which nitrifying organisms reduce nitrite to dinitrogen gas via N2O, especially under anaerobic conditions, and denitrification, in which nitrate is reduced to dinitrogen gas via N2O by denitrifying organisms.

Previous studies had often used acetylene to inhibit N2O production, but this has been found to be unreliable. In contrast, the stable isotope approach used here was able to detect both N2O production and consumption even when reservoirs of N2O were very low. Nitrification was the most important N-transforming process found in these systems, with most N2O produced probably from reduction pathways.