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（S.K. Hamilton）去除氮中的作用过多的氮（N）进入溪流，通常是从农业或城市地区起源于农业或城市地区的硝酸盐，会引起水问题的问题，并且是越来越多的问题。表面和地下水经过景观经常通过湿地和源水流，通常观察到硝酸盐去除。下游的蓄水池和洪泛区可能会进一步去除。 此处提出的研究的灵感来自先前的研究，该研究表明，密歇根州的淡水沉积物中的硝酸盐去除与硫酸盐生产相吻合。试点研究表明，这是一种通过细菌硫化的生物学过程，该过程可能通过硫酸盐氧化，将硝酸盐用作氧化剂代替氧气。所研究的总体假设是，与S氧化有关的硝酸盐还原是许多淡水沉积物中的重要过程。这种沉积物的S在S中并不异常高，就像硝酸盐一样具有天然来源，但也是无处不在的污染物。 在密歇根州西南部的各种湿地，溪流和河流水库和洪泛区中，将研究减少硝酸盐的氧化剂的重要性，并在美国几个位置的雷水流中进行研究，这些地区是地点间实验的研究地点（Linx）。湿地和溪流清除N在农业景观中特别感兴趣，因为河流向沿海水域的出口已与创造缺氧区（例如墨西哥湾）和有害的藻类开花有关。 出于n管理的目的，湿地和溪流恢复应考虑微生物S和N变换之间的可能联系，这取决于n去除速率的控制和最终被去除的N的命运。研究生培训是这项研究不可或缺的，结果将有助于外展和教学活动。