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

了解碳的命运如何受到生物群落的影响是生态系统科学中最大的挑战之一。淡水生态系统，包括溪流，现在被认为是运输、处理和掩埋大量有机物的场所。微生物群落，包括细菌，占溪流中有机物处理的绝大部分，但关于微生物群落如何影响溪流中有机物的命运，还有很多人不知道。该项目将通过研究细菌群落多样性、溪流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被输送到下游来解决这一知识缺口。为了验证pH值和有机物组成的变化会影响河流微生物群落及其处理有机物的能力，将进行一项中生态实验。遗传细菌群落指纹将用于量化细菌群落对实验处理的反应。细菌代谢反应将通过酶测定和总体代谢率来测量。该项目将有助于了解淡水中微生物群落结构与代谢之间的关系。随着流域被人类活动改变，pH值和水生生态系统的有机物输入也在发生变化。由于溪流可以被视为环境变化的哨兵，因此这项研究将深入了解淡水群落对全球变化的反应。本科研究人员将从事工作的各个方面，以进一步他们的科学认识。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育材料，帮助他们解释这项工作和更广泛的生态系统生态学概念。

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.