Recent evidence suggests that the cycling of elements between the soil and the atmosphere can be the result of light-driven non-biological reactions. This project will explore the role of solar radiation as a cause of reactive nitrogen gas emissions from soil. Our understanding of the production of these gases is based on biological processes driven by soil microorganisms. However, preliminary measurements from the Mojave Desert suggest that abiotic processes driven by light may also contribute to nitrogen gas losses. This study will partition abiotic and biotic sources of trace nitrogen gas emissions from desert soils using (1) laboratory measurements of the effect of light intensity on nitrogen gas emissions from soils in which biological activity has either been stimulated or repressed and (2) field measurements utilizing daily variation in solar radiation and seasonal changes in biological activity to identify the role of light in describing patterns of trace nitrogen gas emissions. Gaseous reactive nitrogen compounds produced from soils play an important role in the atmospheric chemistry defining climate and air quality. The findings from this research will both increase our understanding of the global nitrogen cycle and allow us to re-evaluate our predictions of how these processes will change in the future.
