Origins of Nitrous Oxide in Terrestrial Environments: Applications of Isotopes and Isotopomers

Michigan State University, East Lansing MI

Investigators

Abstract

Nitrous oxide is a potent greenhouse gas that retains heat 300 times more efficiently than carbon dioxide. Thus while nitrous oxide is 1000 times less abundant than carbon dioxide its contribution to global warming is significant. Emissions of nitrous oxide from agricultural soils may have a greater impact on global warming than those from carbon dioxide. We do not, however, yet understand how to manage soils to reduce emission of nitrous oxide. This depends on understanding the relative importance of the two predominant processes by which soil microbes produce nitrous oxide, denitrification and nitrification. In this proposal we are the first to apply isotopomers, the measurement of both N atoms in nitrous oxide, to evaluate the origins of this gas. We have demonstrated that such information can distinguish nitrous oxide produced by denitrification and nitrification and will apply isotopomers in a variety of terrestrial environments.