Project: Chemo-Denitrification Reactions in Suboxic Environments

(copied from the NSF award page, May 2011)

Nitrogen in the marine environment is cycled through a complex and imperfectly understood geochemical and microbiologically-mediated transformations, especially in suboxic waters -- the zone between regions of distinct oxygen availability on one hand and the complete absence of oxygen on the other. While some oxidation-reduction reactions in the nitrogen cycle are certainly driven directly by microbial activity, there is evidence that geochemical linkages to the cycling of other redox-senstitive moieties (such as manganese) may also drive some of these nitrogen transformations. In this study, researchers at the University of Washington, in collaboration with colleagues at the Scripps Institution of Oceanography and the Middle East Technical University in Turkey, will study the chemical reaction rates and microbiology of denitrification reactions in the suboxic regions of the Black Sea. High-resolution measurements of nutrients, trace metals, and the key nitrogen species associated with nitrogen cycling under suboxic conditions would be made. The Black Sea will offer an ideal study site for this work because the spatially extensive suboxic zone will permit the fine-scale measurements that would be difficult, if not impossible, in other marine areas, The project should lead to an improved understanding of both the geochemical and microbiological linkages of the nitrogen cycle in suboxic marine waters to the cycling of other redox-sensitive substances in the Black Sea and other marine environments.