Interaction of Soil Nitrogen and Water Cycles Control Trace N-Gas Production

控制氮素时间变化的因素 一氧化二氮（NO）和一氧化二氮（N2 O）的产生 将调查具有明显的雨季和旱季的系统。 更具体地说，研究人员将研究：1）生物和 干旱土壤无机氮和氮素的非生物过程; 2)当干燥的土壤被润湿时，痕量氮气体的来源; 3)变化土壤条件下硝化细菌种群动态 水分和基质的有效性; 4）起源和控制 硝化菌和反硝化菌产生的N 0;以及5）因子 影响N 0和N20从土壤中逃逸。 这些研究将在三个地区的土壤上进行。 西海岸生态系统-橡树草原和针叶林 加州的森林生态系统和 墨西哥 研究氮的最新技术 将使用土壤和微生物种群中的循环。 这些 在氮循环中包括15 N同位素稀释技术 荧光抗体和显微放射自显影 微生物种群的技术。 各个方面 的过程级研究最终将被整合 通过建模。 这项研究的意义在于它将帮助我们 了解土壤水分含量的变化如何影响 产生两种重要的痕量气体，N 0和N20。 硝酸 氧化物是感兴趣的，因为它参与对流层 除其他外，反应会产生臭氧，这是一个主要的反应 低层大气中的污染物。 一氧化二氮是 因为它是一种高效的温室气体， 与全球气候变化有关。 凡士通博士在工作效率方面有很好的记录， 土壤氮素动态复杂区。 的制度化支持 对她来说是上级的。

The factors controlling temporal variations of nitric oxide (NO) and nitrous oxide (N20) production in several systems with distinct wet and dry seasons will be investigated. More specifically, the researchers will examine: 1) biotic and abiotic processes of inorganic-N and N0 production in dry soil; 2) the origin of trace N-gas flushes when dry soils are wetted; 3) dynamics of nitrifying populations under changing soil moisture and substrate availability; 4) origin and control of N0 production by nitrifiers and denitrifiers; and 5) factors affecting escape of N0 and N20 from soil. These studies will be carried out on soils taken from three west-coast ecosystems - the oak-grasslands and coniferous forest ecosystems of California and the deciduous forests of Mexico. State-of-the-art techniques for studying nitrogen cycling in soils and microbial populations will be used. These include 15N isotope dilution techniques in the nitrogen cycling work and fluorescent antibody and micro-autoradiography techniques in the microbial population work. Various aspects of the process-level research will ultimately be integrated through modeling. The significance of this research is that it will help us to understand how changes in soil moisture content affect the production of two important trace gases, N0 and N20. Nitric oxide is of interest because of its involvement in tropospheric reactions which, among other things, create ozone, a major pollutant in the lower atmosphere. Nitrous oxide is of interest because it is a highly efficient greenhouse gas and so is involved in global climate change. Dr. Firestone has a very good record of productivity working in the complex area of soil-N dynamics. The institutional support available to her is superior.