CAREER: Nitrate Isotopes and Biogeochemistry: A Plan for Coupling

生物地球化学是一个新兴的交叉学科，研究生物重要元素的环境通量，而含氮化合物的稳定同位素分布是生物地球化学中一个正在发展的领域。 在这个项目中，普林斯顿大学的一位教师希望通过将本科教育融入他的研究中，利用稳定同位素来了解海洋氮循环，从而促进地球化学作为一个领域的未来。普林斯顿大学社区在地球化学及其与海洋和大气物理学的相互作用方面拥有卓越的专业知识。 作为补充，该大学通过对高级论文的普遍要求，致力于让本科生参与研究活动。 为了将这两个优势联系起来，该项目将提供一个夏季本科研究计划，以资助与高级论文相关的项目，这些项目将受益于并支持研究生在地球化学领域的研究。 在某些情况下，与研究生导师，主要研究者本人和另一名教师或NOAA地球物理流体动力学实验室科学家合作，每个本科生都将从事一个适合高级论文和潜在可验证的项目。 因为该项目也将被设计为进一步研究生导师的研究目标，导师将有适当的专业知识和额外的动机。 夏季研究计划的连续性与论文在下一学年的完成增加了显着的成就和该计划的教育和研究目标之间的真正协同作用的潜力。 该计划建立在主要研究者的努力，让学生在他们的本科生涯的多个阶段参与环境地球科学。硝酸盐是环境中生物可利用氮的普遍存在形式。 基于主要研究者实验室以前的方法开发，研究生和本科生将研究硝酸盐的氮（N）和氧（O）同位素作为N循环的“示踪剂”，重点是海洋环境。 研究将集中在两个项目上，这些项目利用了整个大学的专业知识：（1）硝酸盐同化和反硝化（N循环中的两个关键反应）的N和O同位素耦合动力学的实验室培养、体外分析和现场孵育研究;和（2）将硝酸盐的N和O同位素纳入海洋环流和生物地球化学的数值模型。 在主要研究员实验室生成的海洋数据集的范围内，这些项目将能够量化海洋地球化学过程，否则，这些过程的信号会因同时发生和海洋环流而变得复杂。 这一项目的更广泛影响包括预期将征聘能力很强的学生从事环境地球科学工作，并使未来有影响力的个人接触环境科学研究。 该计划直接涉及的学生人数不多，但它完成了一个多阶段的战略，让学生参与环境地球科学。 此外，它的影响将通过环境地球科学中这种高级本科生活动的校园存在以及该计划作为该领域高级论文支持活动的试验场的作用来放大。

ABSTRACTOCE-0447570Biogeochemistry, which investigates the environmental fluxes of biologically important elements, is an emerging interdisciplinary field, and the use of the stable isotope distributions of nitrogen-bearing compounds is a developing area within biogeochemistry. In this project, a faculty member at Princeton University expects to promote the future of biogeochemistry as a field by integrating undergraduate education into his research into the use of stable isotopes to understand the marine nitrogen cycle.The Princeton University community has remarkable expertise in biogeochemistry and its interaction with the physics of the ocean and atmosphere. Complementarily, the university works to engage undergraduates in research activities through the universal requirement of a senior thesis. To link these two strengths, this project will feature a summer undergraduate research program to fund senior thesis-related projects that benefit from and support the research of graduate students in biogeochemistry. Working with a graduate student mentor, the principal investigator himself, and another faculty member or NOAA Geophysical Fluid Dynamics Laboratory scientist in some cases, each undergraduate will pursue a project that is appropriate for a senior thesis and potentially publishable. Because the project will also be designed to further the research goals of the graduate student mentor, the mentor will have appropriate expertise and additional motivation. The continuity of the summer research program with the completion of the thesis during the next academic year increases the potential for significant accomplishment and true synergy between the educational and research goals of the program. This program builds upon the principal investigator's effort to engage students in the environmental Earth sciences at multiple stages in their undergraduate career.Nitrate is a ubiquitous form of biologically available nitrogen in the environment. Based on previous method development in the principal investigator's laboratory, the graduate students and undergraduates will investigate the nitrogen (N) and oxygen (O) isotopes of nitrate as 'tracers' of the N cycle, focusing on the marine environment. Research will center on two projects that draw upon the expertise from across the university: (1) lab culture, in vitro assay, and field incubation studies of the coupled N and O isotope dynamics of nitrate assimilation and denitrification, two of the critical reactions in the N cycle; and (2) incorporation of the N and O isotopes of nitrate into numerical models of ocean circulation and biogeochemistry. These projects, in the context of the oceanic data sets generated in the principal investigator's laboratory, will allow for the quantification of biogeochemical processes the signals of which are otherwise complicated by their simultaneous occurrence and by ocean circulation. The broader impacts of this project include the anticipated recruitment of highly capable students into the environmental Earth sciences and the exposure of future individuals of influence to scientific studies of the environment. This program directly involves only a modest number of students, but it completes a multi-stage strategy for engaging students in the environmental Earth sciences. Moreover, its impact will be amplified by the campus presence of such advanced undergraduate activities in environmental Earth science and the role of the program as a testing ground for senior thesis-supported activities in this area.