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.

摘要0516076 微生物硫氧化在湿地和溪流脱氮中的作用 (S.K. Hamilton) 过量的氮 (N) 进入溪流，通常来自农业或城市地区的硝酸盐，会造成水质问题，并日益引起人们的关注。流经景观的地表水和地下水经常流经湿地和源头溪流，通常在这些地方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先前研究的启发，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同时发生。初步研究表明，这是一种生物过程，可能是通过细菌利用硝酸盐作为氧化剂代替氧气氧化硫 (S) 来实现的。正在研究的总体假设是，与硫氧化相关的硝酸盐还原是许多淡水沉积物中的一个重要过程。这些沉积物中的硫含量并不异常高，它像硝酸盐一样有天然来源，但也是一种普遍存在的污染物。 我们将在密歇根州西南部的不同湿地、溪流、河流水库和洪泛区，以及作为 Lotic Intersite N 实验 (LINX) 研究地点的美国多个地点的源头溪流中，研究硫氧化剂还原硝酸盐的重要性。湿地和溪流对氮的去除在农业景观中特别重要，因为河流向沿海水域输出氮会导致缺氧区（例如墨西哥湾）和有害藻华的产生。 以氮管理为目的的湿地和河流恢复应考虑微生物硫和氮转化之间可能的联系，这关系到氮去除率的控制和去除的氮的最终命运。研究生培训是这项研究的一部分，其结果将有助于推广和教学活动。