Sulfur isotope study of Phanerozoic carbonate associated sulfate

该奖项是根据2009年颁布的《美国复苏和再投资法案》(公法111-5)资助的。这项提议要求资金支持一名博士生的研究，这名博士生正在努力建立硫同位素比率的记录(涉及所有四种硫同位素)，使用碳酸盐伴生硫酸盐作为海水硫酸盐的替代品，并利用这一记录来检验关于硫循环演化的一个正在形成的假说。具体地说，我们假设，在显生宙中期，硫酸盐和埋藏的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。我们的目标是验证这一假说，并探索其对硫循环的影响和与之的联系，以及如果这种变化得到证实，则阐明这种变化背后的机制。分析和模型计算的初步结果构成了将要检验的假设的基础，并在本提案的正文中作了更详细的说明。这项提案要求为第二个两年的研究提供资金，并要求提供毕业生津贴、标准福利、学费、分析费用和参加两次会议的旅费，在会议上将展示结果。不需要资金来支持PI，但需要资金来支持一名本科生研究人员。这是实验室政策的一部分，目的是让本科生参与进来，我们认为这对他们来说是有好处的，因为他们可以将他们整合到高水平的研究项目中，而博士后学生的专业发展则是通过将他放在导师和研究员的角色中来实现的。在过去，这些项目产生了新的想法和独立的项目，这些项目可能构成马里兰大学高级论文项目的基础。其他更广泛的影响包括在公共演讲和其他专业活动中纳入研究结果和研究模式。

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.