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

一氧化二氮是一种强有力的温室气体，其保持热量的效率是二氧化碳的300倍。 因此，尽管一氧化二氮的含量比二氧化碳少1000倍，但它对全球变暖的贡献是巨大的。 农业土壤排放的一氧化二氮对全球变暖的影响可能比二氧化碳更大。 然而，我们还不知道如何管理土壤以减少一氧化二氮的排放。 这取决于理解土壤微生物产生一氧化二氮的两个主要过程的相对重要性，即反硝化和硝化。 在这个建议中，我们是第一个应用同位素，测量一氧化二氮中的两个N原子，以评估这种气体的起源。 我们已经证明，这些信息可以区分由反硝化和硝化作用产生的一氧化二氮，并将在各种陆地环境中应用同位素。

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.