CAREER: Assessing the Reactivity and Diversity of Neutrophilic Iron-Oxidizing Bacteria in Terrestrial Aquatic Environments

尽管它们无处不在，能见度很高，但铁锈色氧化铁矿床仍然是人们鲜为人知的河流、湖泊和泉水的特征。直到最近，人们一直认为这些沉积物是由非生物化学过程形成的；然而，最近的研究表明，这些沉积物往往是特定的铁氧化细菌作用的结果。这些细菌氧化铁的性质可能与地球化学家在实验室实验中传统上用来探测环境和地球化学反应的非生物氧化物有很大的不同。该项目的总体目标是描述这些氧化铁矿床的结构、反应性和生物多样性，以更好地了解它们可能在环境中扮演的多方面角色。为了实现这些目标，我们将进行一系列野外、实验室、微生物和光谱分析，以确定氧化铁及其形成相关细菌的关键性质。这个项目的结果将促进对铁在水环境中行为的基本理解。由于氧化铁是常见营养物质和污染物的有效吸附剂，研究结果还可能为了解天然氧化铁如何影响环境中溶解物种的流动性和分布提供新的见解。该项目还纳入了旨在吸引学生、教师和普通公众参与的综合教育和宣传部分。在收集数据的过程中，我们将邀请一群高中教师和学生在他们的学校进行演讲，并带领实地考察当地的氧化铁矿藏。参与这项活动的高中教师将在夏季对PI的实验室进行研究访问，他们将利用他们帮助收集的相同田野样本进行实验。该项目的另一个产品将是一个基于地图的网络资源，它将提供实地数据，帮助学生、教师和其他公民了解生物地球化学过程在当地环境中的重要性。这些活动将有助于扩大学生和公众对地球化学和地球生物学重要性的认识，并有助于激发他们对周围世界正在发生的自然过程背后的科学的好奇心。

Despite their ubiquity and high visibility, rust colored iron oxide deposits remain a poorly understood feature of rivers, lakes, and springs. Until recently, it was assumed that these deposits were formed by abiotic chemical processes; however, recent studies have shown that these deposits often result from the action of specific iron oxidizing bacteria. These bacterial iron oxides may have very different properties than those abiotic oxides that are traditionally used by geochemists in laboratory experiments designed to probe environmental and geochemical reactivity. The overall goal of the project is to characterize the structure, reactivity, and biological diversity of these iron oxide deposits to better understand the multifaceted roles they may play in the environment. To achieve these goals, we will conduct a suite of field, laboratory, microbiological, and spectroscopic analyses aimed at determining key properties of both the iron oxides and the bacteria associated with their formation.Results from this project will advance the fundamental understanding of the behavior of iron in aquatic environments. Because iron oxides are effective sorbents of common nutrients and contaminants, results may also provide new insights into how natural iron oxides affect the mobility and distribution of dissolved species in the environment. The project also incorporates an integrated education and outreach component designed to engage students, teachers, and the general public. In the process of collecting data, we will engage a group of high school teachers and students by conducting presentations at their schools and leading field trips to sample local iron oxide deposits. This activity will be reinforced by summer research visits to the PI's laboratory by participating high school teachers, who will conduct experiments that utilize the same field samples they helped to collect. An additional product of this project will be a map-based web resource that will present field data to help students, teachers, and other citizens understand the importance of biogeochemical processes in their local environment. These activities will help to expand awareness of the importance of geochemistry and geobiology to students and the public, and help to stimulate their curiosity about the science behind natural processes that are occurring in the world around them.