Biogenic and Abiotic Processes Impacting Reactive Nitrogen Oxide Fluxes to and from Soil

Authors

Jonathan D. Raff^1,2,3* (jdraff@indiana.edu)

Institutions

¹O’Neill School of Public and Environmental Affairs, Indiana University–Bloomington, IN; ²Department of Chemistry, Indiana University–Bloomington, IN; ³Integrated Program in the Environment, Indiana University–Bloomington, IN

Abstract

Nitrogen (N) cycle processes play a crucial role in regulating the overall abundance of oxidized inorganic nitrogen in terrestrial ecosystems and are responsible for initiating the subsequent loss of soil N via volatilization and leaching. This poster will outline the laboratory’s effort to understand the sources and sinks of reactive nitrogen oxides (nitric oxide, nitrogen dioxide, nitrous acid) with the ultimate goal of improving how fluxes of reactive nitrogen oxides are represented in chemical-transport models. This presentation will share results of field campaigns aimed at studying the impact of vegetation on reactive nitrogen oxide emissions from soil, in addition to the contribution of freshly senesced leaves in the autumn. Researchers found that plants compete with microbes for nutrients, which has an important impact on modulation of released gases. In addition, the leaves of some deciduous tree species become sources of nitric oxide in forested regions when nitrogen that is not reabsorbed during senescence is released to the atmosphere. This research was enabled by the development of a new catalyst capable of allowing measurement of nitric oxide, nitrogen dioxide, and nitrous acid in real time in both the field and laboratory setting. Implications for atmospheric chemistry will be discussed.