4. 4. Nitric oxide flux from thawing

General patterns of responses

Increased soil NO fluxes following thawing have been observed only in a field study (Laville et al., 2011) and in a laboratory incubation study (Yao et al., 2010). In a French crop field, NO fluxes following thawing increased up to 10 ng N m−2 s−1 and decreased to pre-event values within 24h while the flux average was 1.7 to 2.3 ng N m−2 s−1 in two years (Laville et al., 2011). Incubation with the soils of steppe, mountain meadow, sand dune and marshland in Inner Mongolia showed that NO fluxes was 0.5−8.0 μg N m–2 h–1 at -10 oC and it increased to around 30 μg N m–2 h–1 following thawing (at 5 oC) (Yao et al., 2010). The relative lack of studies on this subject—the response of NO to both rewetting and thawing—suggests that there is a large research potential to elucidate drivers and constrain the NO flux response.