Role of Microbial Sulfur Oxidation in Nitrogen Removal by Wetlands and Streams

微生物硫氧化在湿地和溪流脱氮中的作用

• 批准号: 0516076
• 负责人: Stephen Hamilton
• 金额: $ 38.32万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-10-01 至 2010-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0516076&HistoricalAwards=false
• 关键词: Role; Microbial; Sulfur; Oxidation; Nitrogen

Abstract0516076 Role of microbial sulfur oxidation in nitrogen removal by wetlands and streams (S.K. Hamilton)Excessive nitrogen (N) entering streams, often originating as nitrate from agricultural or urban areas, creates problems with water-quality and is a growing concern. Surface and groundwater flow through landscapes often passes through wetlands and headwater streams, where nitrate removal is typically observed. Further removal may occur in downstream impoundments and floodplains. The research proposed here was inspired by previous studies that showed that nitrate removal from freshwater sediments in Michigan coincided with sulfate production. Pilot research indicates that this is a biological process that could occur via sulfur (S) oxidation by bacteria that utilize nitrate as an oxidant in place of oxygen. The overarching hypothesis under investigation is that nitrate reduction linked to S oxidation is an important process in many freshwater sediments. Such sediments are not unusually high in S, which like nitrate has natural sources, but also is a ubiquitous pollutant. The importance of nitrate reduction by S oxidizers will be investigated across diverse wetlands, streams, and riverine reservoirs and floodplains in southwestern Michigan, and in headwater streams at several U.S. locations that are study sites for the Lotic Intersite N Experiment (LINX). The removal of N by wetlands and streams is of particular interest in agricultural landscapes because N export by rivers to coastal waters has been implicated in creating hypoxic zones (e.g., the Gulf of Mexico) and harmful algal blooms. Wetland and stream restoration for the purpose of N management should consider the possible linkage between microbial S and N transformations, which bears on the controls of N removal rates and the eventual fate of the N that is removed. Graduate student training is integral to this research, and the results will contribute to outreach and teaching activities.

微生物硫氧化在湿地和溪流脱氮中的作用（S.K.汉密尔顿）过量的氮（N）进入河流，通常来自农业或城市地区的硝酸盐，造成水质问题，并日益受到关注。地表水和地下水流经景观通常会经过湿地和源头溪流，在那里通常会观察到硝酸盐的去除。下游蓄水池和洪泛区可能会进一步清除。 这里提出的研究受到了以前研究的启发，这些研究表明密歇根州淡水沉积物中硝酸盐的去除与硫酸盐的产生相一致。初步研究表明，这是一个生物过程，可能通过细菌利用硝酸盐代替氧气作为氧化剂氧化硫（S）而发生。目前正在调查的总体假设是，硝酸盐还原与S氧化是一个重要的过程，在许多淡水沉积物。这些沉积物中的硫含量并不高，硫和硝酸盐一样有天然来源，但也是一种普遍存在的污染物。 硝酸盐还原S氧化剂的重要性将在不同的湿地，溪流，河流水库和漫滩在密歇根州西南部，并在源头流在美国的几个位置是研究地点的Lotic Intersite N实验（LINX）。湿地和溪流对氮的去除在农业景观中特别令人感兴趣，因为河流向沿海沃茨的氮输出与创造缺氧区（例如，墨西哥湾）和有害藻华。 湿地和流恢复N管理的目的，应考虑微生物的S和N的转换，这对N的去除率的控制和最终的命运，被删除的N之间的可能联系。研究生培训是本研究不可或缺的一部分，其结果将有助于推广和教学活动。