CAREER: Nitrate Isotopes and Biogeochemistry: A Plan for Coupling

生物地球化学是一门新兴的交叉学科，它研究生物重要元素的环境通量，而利用含氮化合物稳定的同位素分布是生物地球化学的一个发展方向。在这个项目中，普林斯顿大学的一名教员希望通过将本科教育整合到他对使用稳定同位素来了解海洋氮循环的研究中来促进生物地球化学作为一个领域的未来。普林斯顿大学社区在生物地球化学及其与海洋和大气物理的相互作用方面拥有非凡的专业知识。作为补充，该大学致力于通过高级论文的普遍要求让本科生参与研究活动。为了将这两个优势联系起来，这个项目将以暑期本科生研究计划为特色，以资助与高级论文相关的项目，这些项目受益于并支持生物地球化学研究生的研究。在某些情况下，与研究生导师、首席研究员本人和另一名教职员工或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并有可能发表的项目。由于该项目还将被设计为促进研究生导师的研究目标，因此导师将拥有适当的专业知识和额外的动力。暑期研究计划的连续性与下一学年论文的完成增加了取得重大成就的潜力，以及该计划的教育和研究目标之间的真正协同。这项计划建立在首席研究员的努力基础上，让学生在本科职业生涯的多个阶段参与环境地球科学。硝酸盐是环境中普遍存在的一种生物可用氮。在首席研究员实验室以前的方法开发的基础上，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的N和O同位素耦合动力学的实验室培养、体外分析和野外培养研究，这是N循环中的两个关键反应；以及(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。在首席调查员实验室产生的海洋数据集的背景下，这些项目将能够对生物地球化学过程进行量化，这些过程的信号在其他方面因同时发生和海洋环流而变得复杂。该项目的更广泛影响包括预期招收高能力学生进入环境地球科学，以及使未来有影响力的个人接触环境科学研究。这个项目直接涉及的学生数量不多，但它完成了一个让学生参与环境地球科学的多阶段战略。此外，它的影响将被放大，因为校园里存在这样的环境地球科学高级本科生活动，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。

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.