The Ocean Nitrogen Imbalance Paradox: Environmental Controls on the Denitrification Isotope Effect

海洋氮失衡悖论：反硝化同位素效应的环境控制

• 批准号: 1233897
• 负责人: Julie Granger
• 金额: $ 23.1万
• 依托单位: University of Connecticut
• 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=1233897&HistoricalAwards=false
• 关键词: Ocean; Nitrogen; Imbalance; Paradox; Environmental

Intellectual Merit: This study will test the sensitivity of the amplitude of the denitrification isotope effect to culture conditions pertinent to the ocean environment. The isotope effect amplitude will be explored with respect to electron donor, trace oxygenation, and temperature, in both batch and continuous culture experiments of denitrifiers. The proposed work will also involve measurements of the enzymatic isotope effect of the respiratory nitrate reductase of denitrifiers, measurements of its enzymatic activity among cultures, and examination of cellular nitrate transport kinetics of denitrifying strains. The experiments are designed to reveal the physiological basis of the modulation of the isotope effect amplitude, which will further resolve this manifestation in the environment. Broader Impacts: In regards to the broader significance and importance of this study, these new experimental data will provide a basis for integration of nitrogen isotope dynamics in ocean models to test how key environmental parameters can affect the global ocean distribution of nitrogen isotopes. Moreover, the proposal will provide support for a graduate student, who will be introduced to a broad range of techniques and sub-disciplines, from microbiology and enzymology, to oceanography and stable isotope biogeochemistry. The project involves an early career female PI, who will mentor one graduate student throughout the project.

智力优点：这项研究将测试反硝化同位素对与海洋环境相关的培养条件的振幅的敏感性。在脱脂子的批处理和连续培养实验中，将探索有关电子供体，痕量氧合和温度的同位素效应振幅。拟议的工作还将涉及对硝酸盐还原剂的酶同位素效应的测量，硝酸盐还原酶的二脂剂，其在培养物中的酶促活性的测量以及对硝酸盐二硝化菌株的细胞硝酸盐转运动力学的检查。该实验旨在揭示同位素效应振幅调节的生理基础，这将进一步解决环境中的这种表现。更广泛的影响：关于这项研究的更广泛的意义和重要性，这些新的实验数据将为海洋模型中氮同位素动力学的整合提供基础，以测试关键环境参数如何影响氮同位素的全球海洋分布。 此外，该提案将为研究生提供支持，该研究生将被介绍到从微生物学和酶学到海洋学和稳定的同位素生物地球化学的广泛技术和子学科。该项目涉及一个早期的职业女性PI，他们将在整个项目中指导一名研究生。