Does Bacterial Community Structure Covary with Functional Response of Gradients of Dissolved Organic Carbon

河道下面和附近的沉积物统称为下流带（下流带和流变带，因此，在水流下面）。这些沉积物中的微生物群落依赖于进入潜流带的地表水提供的物质。该研究项目将研究这些微生物如何对进入该区域的溶解有机碳供应的变化作出反应。主要研究人员将改变实验中生态系统设施的碳供应，以确定该区域的细菌是简单地改变其生长速度，还是一组新的细菌随着碳供应的变化而占据主导地位。通过从不同的深层沉积物中提取细菌DNA，他们将确定深层细菌群落之间的相似性。研究人员将完善从低渗沉积物中提取DNA的技术，并进行DNA-DNA杂交分析。溪流生态学家已经认识到，可见的河道下面的沉积物是各种水生生物的重要栖息地。发生在溪流中的许多化学变化可归因于居住在靠近溪流的地下沉积物中的微生物的作用。人类活动倾向于增加河流中溶解有机碳，了解微生物群落对河流化学变化的响应将有助于加强河流水质管理和河流群落功能。

The sediments below and adjacent to the stream channel are collectively called the hyporheic zone (hypo - beneath and rheos - flow, therefore, below the flow). The microbial communities in these sediments rely on the supply of materials from surface water entering the hyporheic zone. This research project will examine how these microbes respond to variations in the supply of dissolved organic carbon entering this zone. The principal investigators will vary carbon supply in an experimental mesocosm facility to determine whether the bacteria in this zone simply change their growth rates or whether a new set of bacteria become predominant as the carbon supply changes. By extracting bacterial DNA from samples collected from different hyporheic sediments they will determine the similarity among hyporheic bacterial communities. The investigators will perfect techniques to extract DNA from hyporheic sediments and conduct DNA-DNA hybridization assays. Stream ecologists have recognized that the sediments beneath the visible stream channel are an important habitat for a wide range of aquatic organisms. Many of the chemical changes that occur in stream water can be attributed to the action of microbes inhabiting the subsurface sediments adjoining streams. Human activity tends to increase dissolved organic carbon in streams, and understanding the response of microbial communities to chemical changes in streams will enhance management of stream water quality and stream community function.