Dentrification, the microbially mediated production of (N2O) and (N2), from desert systems in the Southwest will be studied. Measurements of denitrification potentials will be made on soil cores from three desert ecosystems. Data from this research will improve our understanding of the nitrogen cycle in desert ecosystems and it will also help us to interpret the importance of desert ecosystems as sources of N2O, a major greenhouse gas. Measurements of denitrification potentials will be made on soil cores from three desert ecosystems - the Great Basin, Mojave and Chihuahuan deserts. In addition laboratory studies will be conducted to determine what factors control denitrification in deserts and what biochemical pathways are responsible for N2O production in these soils. A state-of-the-art gas chromatographic technique (G3Ni electron capture) will be used for the N2O analyses. The reserach will be coordinated from Duke University, although much of the field work will be done at the Long-Term Ecological Research site in southern New Mexico - New Mexico State's Jornada site in the Chihuahuan Desert. The facilities available in support of the research at Duke and at the New Mexico State are very good, and the personnel to be involved in the work are of high quality. The Ecosystem Studies Program recommends support of this grant request.
