EAGER: Application of high precision isotope tracer measurements to resolve rates of aquatic denitrification

EAGER：应用高精度同位素示踪测量来解析水生反硝化速率

• 批准号: 1245725
• 负责人: Nathaniel Ostrom
• 金额: $ 8.29万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1245725&HistoricalAwards=false
• 关键词: EAGER; Application; precision; isotope; tracer

Denitrification is the natural process by which nitrate is reduced to harmless N2 gas. Denitrification reduces loading of nitrate to the biosphere, thereby minimizing coastal eutrophication and hypoxia and emissions of the greenhouse gas, nitrous oxide. Watersheds represent the greatest sink for natural and anthropogenic nitrate; however, rates of denitrification, particularly at ecosystem scales, are poorly understood. Denitrification in streams can be evaluated at ecosystem scales by addition of nitrate enriched in the stable nitrogen isotope 15N and measurement of the accumulation of 15N in N2. This study will develop novel analytical methodology for vastly improving the accuracy and precision of the N2 stable isotope ratio, which will enable application of 15N-nitrate tracer studies in environments where it is currently impractical to do so. EAGER funding is appropriate as this method development is exploratory; nonetheless the project has great potential to transform the approach for and knowledge of the denitrification process.Excessive nitrate loading and its role in eutrophication is one of the most significant impacts of a large and growing human population. Thus, the broader significance and potential impacts of this research are that the methodology proposed will provide ecosystem managers information to understand natural rates of nitrate removal as well as a foundation to manage natural and man-made environments to foster denitrification.

反硝化作用是将硝酸盐还原为无害的N2气体的自然过程。反硝化作用减少了硝酸盐对生物圈的负荷，从而最大限度地减少了沿海富营养化和缺氧以及温室气体一氧化二氮的排放。 流域是自然和人为硝酸盐的最大汇，然而，反硝化速率，特别是在生态系统尺度上，知之甚少。 通过添加富含稳定氮同位素15 N的硝酸盐和测量N2中15 N的积累，可以在生态系统尺度上评估溪流中的反硝化作用。 这项研究将开发新的分析方法，大大提高N2稳定同位素比的准确性和精密度，这将使15 N-硝酸盐示踪剂研究在目前不切实际的环境中应用。 EAGER的资助是适当的，因为这种方法的发展是探索性的;尽管如此，该项目有很大的潜力，以改变的方法和知识的反硝化process. The过量的硝酸盐负荷及其在富营养化的作用是一个大的和不断增长的人口最显着的影响之一。因此，更广泛的意义和潜在的影响，这项研究的方法将提供生态系统管理人员的信息，了解自然的硝酸盐去除率，以及管理自然和人为的环境，以促进反硝化的基础。