Fertilization of Salt Marsh Ecosystems: Using Molecular Techniques to Evaluate the Effects of Nitrogen Enrichment on Sediment Microbial Communities

由于沿海水域对人类和经济的重要性，沿海水域的营养富集日益受到社会关注。该项目的目标是了解从土地中增加的营养物质是如何改变盐沼中处理氮的细菌的数量和类型的。有两个主要的科学目标。首先，一种新的、快速的、高分辨率的细菌基因测序技术？DNA标签法？将测试它在盐沼沉积物中是否有效。其次，对氮循环中至关重要的细菌基因的具体分析将被量化，以确定微生物群落在两年的氮肥施肥后是否发生了显著变化。人类对沿海水域的影响正在改变沼泽和河口，并影响它们为社会提供的服务，例如作为娱乐场所和作为商业上重要的鱼类和贝类的苗圃。在河流和地下水到达河口之前，盐沼净化了水中的人类来源的营养物质，这样有助于防止营养物质超载或富营养化。这些清洁活动是由沉积物中的细菌介导的。尽管它们很重要，但这些沉积物中的细菌以及人类引起的细菌群落变化却鲜为人知。该项目将提供有关有前途的新技术和细菌因人类活动而变化的方式的信息。

Nutrient enrichment of coastal-zone waters is of increasing societal concern due to the importance of these waters to people and economies. The goal of this project is to understand how increased amounts of nutrients from land change the numbers and types of nitrogen-processing bacteria in salt marshes. There are two primary scientific objectives. First, a new, rapid, high-resolution technique for sequencing selected bacterial genes ? the DNA tag method ? will be tested to see if it works in salt-marsh sediments. Second, specific analyses of bacterial genes that are a vital part of the nitrogen cycle will be quantified to determine if microbial communities change significantly in response to two years of fertilization with nitrogen. Human impacts on coastal waters are altering marshes and estuaries and affecting the services they provide to society, such as areas for recreation and as nursery grounds for commercially important fish and shellfish. Salt marshes cleanse waters of human-derived nutrients before rivers and groundwaters reach estuaries, and in this way help prevent nutrient overload or eutrophication. These cleansing activities are mediated by bacteria in the sediments. Despite their importance, bacteria in these sediments, and human-induced changes in bacterial communities, are little known. This project will provide information on promising new techniques and on ways bacteria change as a result of human activities.