Sulfur isotope study of Phanerozoic carbonate associated sulfate

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。该提案要求资助一名博士生的研究，该博士生正致力于建立硫同位素比率的记录（包括所有四种硫同位素），使用碳酸盐相关硫酸盐作为海水硫酸盐的代理，并使用该记录来测试关于硫循环演化的一个正在发展的假设。具体来说，我们假设在显生宙中期硫酸盐和埋藏黄铁矿之间的分馏程度发生了变化，这表明参与硫循环的生物途径发生了变化。我们的目标是测试这一假设，并探讨其影响和与硫循环的联系，以及阐明变化背后的机制，如果这种变化得到证实。分析和模型计算的初步结果构成了有待检验的假设的基础，并在本建议的正文中作了更详细的描述。该提案要求资助第二个两年的研究，并要求提供研究生津贴、标准福利、学费、分析费用和参加将介绍结果的两次会议的旅费。不要求资金支持PI，但要求资金支持本科生研究员。这是实验室政策的一部分，让本科生参与进来，我们相信这有利于他们参与高水平的研究项目，也有利于博士后学生的专业发展，让他既扮演导师的角色，又扮演研究员的角色。在过去，这些项目会产生新的想法和独立的项目，这些项目可能会成为马里兰大学毕业论文项目的基础。其他更广泛的影响包括PI在公开演讲和其他专业活动中不参与研究成果和研究模式。

This award is funded under the American Recovery and Reinvestment Actof 2009 (Public Law 111-5). This proposal requests funds to support research by a Ph.D. student, who is working to establish a record of sulfur isotope ratios (involving all four sulfur isotopes) using carbonate associated sulfate as a proxy of seawater sulfate and using this record to test a developing hypothesis about the evolution of the sulfur cycle. Specifically, we hypothesize that there was a change in the magnitude of the fractionation between sulfate and buried pyrite that occurred in the middle Phanerozoic, and that points to a change in the biological pathways involved in sulfur cycling. We aim to test this hypothesis and to explore its implications for and connections with the sulfur cycle as well as to elucidate the mechanisms behind the change if such change is confirmed. Preliminary results of analyses and of model calculations form the basis for the hypotheses that are to be tested and are described in more detail in the body of this proposal. This proposal requests funds to support the second two years of research and includes a request for a graduate stipend, standard benefits, tuition, analytical costs and travel to two meetings where results will be presented. No funds are requested to support the PI, but funds are requested to support an undergraduate researcher. This is done as part of a laboratory policy to involve undergraduates, which we believe carries benefits for them by integrating them in high-level research projects, and for the postdoctoral student's professional development by placing him in the role of mentor as well as researcher. In the past these projects have resulted in new ideas being developed and independent projects that may form the basis for University of Maryland senior thesis projects. Other broader impacts include the ncorporation of research results and the research model in public presentations and other professional activities by the PI.