ausblenden:
Schlagwörter:
-
Zusammenfassung:
In EGU General Assembly 2024, Vienna, Austria & Online, 27 April–2 May 2025
Nitric oxide (NO) and nitrous acid (HONO) are important reactive atmospheric trace gases. As part of the nitrogen (N) cycle, ammonia oxidizing nitrifiers in soils are recognized as key producers of these gases, impacting near-surface nitrogen oxide (NOx = NO + NO2) and ozone (O3) concentrations. The nitrification process results in the production of nitrite (NO2-), subsequently protonated in the liquid phase to form HONO, and NO, which are both emitted as gases. However, there is limited understanding of the coupled processes causing the simultaneous emission NO and HONO from drying soils incorporating ammonia oxidizing nitrifiers. Here, we combined experimental in-vitro studies of ammonia-oxidizing bacteria with a mechanistic modelling approach to investigate the mechanisms triggering gaseous NO and HONO emissions. We found out that several abiotic processes, such as NO auto-oxidation, Fe2+ catalysis, and soil moisture dynamics crucially influence the overall emission as well as the partitioning of reactive N. This, in turn, impacts the hydroxyl radical (OH) budget and soil N retention. Modelling allowed us to elucidate the interactions between biological and environmental processes under varying soil hydration conditions for different field scenarios, such as the effects of fertilization. This analysis suggests potential strategies for effectively managing the release of soil-derived NOx and OH emissions.
