Sulfur isotope study of sulfide oxidation products: Great Marsh of Delaware and Green Lake NY

研究目标：研究将侧重于描述硫化物氧化产物（多硫化物，连多硫酸盐，硫代硫酸盐，亚硫酸盐和硫酸盐）的硫同位素效应的表达在两个水系统的情况下，硫化物氧化发生的研究。我们将在2009年3月、6月和8月期间从特拉华州大沼泽收集样本，并在2009年夏季期间从绿色湖（一个半融湖）收集样本。研究的目的是硫化物氧化产物的分离和同位素表征。该研究将涉及调整收集这些化合物的技术，以便可以对四种硫同位素进行测量，并旨在表征和探索中间体的同位素组成，pH值和生物活性之间的联系。这项研究工作的总体目标是开发一个基于四种硫同位素的协议，对自然水生系统和沉积物中硫化物氧化的生物和非生物途径进行定量限制。这项工作是植根于一个基本的前提，即小的同位素效应之间的产品和反应物以及各种氧化产物之间将以不同的方式表示，这取决于硫的形态和反应途径。这项研究是我们小组和其他人正在进行的更大努力的一部分，并扩展了我们最近的实验室培养工作，包括硫酸盐还原剂，硫中间化合物反硝化剂和生物硫化物氧化。拟议活动的更广泛影响：这项研究的结果将准备在同行评议的期刊上发表。我们预计，这项研究的结果将进行地球化学系统中的硫循环的其他研究的影响，并提供一个上下文，可用于告知我们的理解与硫化物氧化在硫循环（现在和过去）的同位素效应的意义。拟议的活动将包括大学生的参与，并将纳入PI的更广泛的活动。

Research Goals: Research will focus on describing the expression of sulfur isotope effects of sulfide oxidation products (polysulfides, polythionates, thiosulfate, sulfite, and sulfate) in two aqueous system case studies where sulfide oxidation occurs. We will collect samples from the Delaware Great Marsh during March, June, and August of 2009 and from Green Lake (a meromictic lake) during summer 2009. The aim of the study will be the isolation and isotopic characterization of the products of sulfide oxidation. The research will involve the adaptation of techniques for collection of these compounds so that measurements of the four sulfur isotopes can be made and with the purpose of characterizing and exploring the connections between the isotopic composition of the intermediates, pH, and biological activity. The overarching goal of this research effort is to develop a protocol based on four sulfur isotopes to place quantitative constraints on biological and abiotic pathways for sulfide oxidation in natural aquatic systems and in sediments. The work is rooted in the underlying premise that small isotope effects between products and reactants as well as between the variety of oxidation products will be expressed in different ways depending on the speciation of sulfur and the reaction pathways. This research is part of a larger effort underway by our group and others and extends our recent laboratory culture work with sulfate reducers, sulfur intermediate compound disproportionators, and biological sulfide oxidation.Broader Impacts of Proposed Activity: The results of this research will be prepared for publication in peer-reviewed journals. We anticipate that the outcomes of this research will carry implications for other studies of cycling of sulfur in geochemical systems and provide a context that can be used to inform our understanding of the significance of isotopic effects associated with sulfide oxidation in the sulfur cycle (present and past). The proposed activity will include involvement of undergraduates and will be incorporated into the broader activities of the PI.