9224587 Mikita This award supports Professor Michael Mikita of California State University at Bakersfield to collaborate in environmental chemistry research with Professor H.-D. Ludemann of the Institute of Biophysics and Physical Biochemistry of the University of Regensburg, Germany. The goal of their research is to gain a better understanding of how soil organic matter affects the nitrogen cycle in soils, by studying the organic reaction mechanisms underlying chemodenitrification. Specifically, they propose to study the reaction of selected humic substances and models with Nitrogen-15 (15N) enriched reagents under conditions expected in soils. In addition, they will seek to improve methods for the 15N-NMR analyses of these reaction products and work to discover the mechanisms of these reactions. Although preliminary studies suggest novel insights into this complex chemistry, further work has been limited by the NMR facilities available to Dr. Mikita. His German collaborator, Professor Ludemann, is a recognized authority in this area and has a world class laboratory with all the instrumentation necessary to carry out the proposed research. The natural chemistry of nitrogen in soils and air remains very poorly understood. Anthropogenic sources of nitrogen oxides include the burning of carbon-based fuels and the use of nitrogenous fertilizers, both of which have been increasing rapidly in the past century. In the presence of soil organic matter, these nitrogen compounds undergo reactions (known generally as chemodenitrification) that release gaseous forms into the air. Now, there is growing concern over the influence of these nitrogen oxides on ozone depletion and global atmospheric processes. Through the combination of expertise, facilities and interests brought to bear by this U.S.-German collaboration, progress will be made in understanding soil-based reactions of nitrogen compounds which are potentially relevant to climate change. ***
