Dissertation Research: Environmental Controls on Stream Bacterial Community Structure & Metabolic Function

了解生物群落如何影响碳的命运是生态系统科学面临的最大挑战之一。淡水生态系统，包括溪流，现在被认为是运输、加工和埋葬大量有机物质的场所。微生物群落，包括细菌，占溪流中有机物处理的绝大多数，但关于微生物群落如何影响溪流中有机物的命运，还有许多未知之处。这个项目将通过研究细菌群落多样性、溪水化学和有机物组成如何影响有机物是被溪流微生物消耗还是向下游输送来解决这一知识差距。将进行一项中游实验，以检验pH值和有机质组成的变化将影响溪流微生物群落及其处理有机物的能力的假设。遗传细菌群落指纹将被用来量化细菌群落对实验治疗的反应。细菌的代谢反应将通过酶分析和总体代谢率来测量。这个项目将有助于理解淡水微生物群落结构和新陈代谢之间的关系。随着人类活动改变流域，输入到水生生态系统的pH值和有机物也在变化。由于溪流可能被视为环境变化的哨兵，这项研究将深入了解淡水社区对全球变化的反应。本科生科研人员将从事各个方面的工作，以加深对科学的理解。研究结果将在科学会议和期刊上公布。将为当地小学生编写教材，帮助他们解释这项工作和更广泛的生态系统生态概念。

Understanding how the fate of carbon is influenced by biological communities is one of the greatest challenges in ecosystem science. Freshwater ecosystems, including streams, are now recognized as sites for the transport, processing, and burial of substantial amounts of organic matter. Communities of microbes, including bacteria, account for a vast majority of the processing of organic matter in streams, but there is much that is not known about how microbial communities impact the fate of organic matter in streams. This project will address this knowledge gap by studying how bacterial community diversity, stream water chemistry, and organic matter composition influence whether organic matter is consumed by stream microbes or transported downstream. A mesocosm experiment will be conducted to test the hypothesis that changes in pH and organic matter composition will impact the stream microbial community and its ability to process organic matter. Genetic bacterial community fingerprints will be used to quantify how the bacterial community responds to the experimental treatments. Bacterial metabolic responses will be measured using enzyme assays and overall metabolic rates.This project will contribute to understanding of the relationship between microbial community structure and metabolism in freshwaters. As watersheds are altered by human activity, pH and organic matter inputs to aquatic ecosystems are also changing. Since streams may be viewed as sentinels for environmental change, this study will generate insight into the response of freshwater communities to global change. Undergraduate researchers will be engaged in all aspects of the work to further their scientific understanding. Results will be communicated at scientific meetings and in journals. Educational materials will be developed for local primary school students that assist in interpreting this work and broader concepts of ecosystem ecology.