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

流道下方和附近的沉积物统称为浅水区(次流层和流变层，因此，流层以下)。这些沉积物中的微生物群落依赖于进入潜水带的地表水的物质供应。这项研究项目将研究这些微生物如何应对进入该区域的溶解有机碳供应的变化。主要研究人员将在一个实验的中微体设施中改变碳供应，以确定该区域的细菌是否只是改变了它们的生长速度，或者是否新的一组细菌随着碳供应的变化而变得主导。通过从不同的水生沉积物中提取细菌DNA，他们将确定水生细菌群落之间的相似性。研究人员将完善从海底沉积物中提取DNA的技术，并进行DNA-DNA杂交分析。河流生态学家已经认识到，可见河流河道下的沉积物是各种水生生物的重要栖息地。溪水中发生的许多化学变化可以归因于栖息在溪流附近地下沉积物中的微生物的活动。人类活动往往会增加溪流中的溶解有机碳，了解微生物群落对溪流中化学变化的响应将加强溪流水质和溪流群落功能的管理。

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.