RoL: FELS: RAISE: Collaborative Research: Watershed Rules of Life

河流是大陆的循环系统，将陆源水、污染物和元素输送到海洋。它们也是拥有独特生物体、食物网和微生物群落的地点，这些微生物群落可以在向海洋运输这些物质的过程中转化这些物质。微生物是这些转变的引擎，具有相当大的能力来去除或改变重要元素(例如碳、氮、磷、汞、砷)，产生温室气体，并支持食物网。然而，由于水流每天的巨大变化，以及横跨景观的溪流和河流类型的巨大差异，理解河流微生物如何影响河流的化学很困难。该项目将研究一套管理河流水柱微生物群落建立的“分水岭生命法则”，这些微生物群落对于理解河流作为循环系统至关重要。研究人员提出了一系列假设，将微生物生态学添加到水文学和地貌学的脚手架上，以研究这些分水岭生命法则。这一假设将通过实地工作和在美国各地的不同流域进行建模来验证。通过这些研究获得的知识将使人们对美国和世界其他温带地区的河流有更广泛的了解。调查人员将与耶鲁纽黑文Promise实习项目互动，该项目为来自纽黑文的对STEM感兴趣的学生提供实习机会。雷蒙德教授还将与朱雀社区学校的学生进行互动。该项目将培养马萨诸塞州大学、俄亥俄州立大学和耶鲁大学的研究生和本科生。调查结果将被纳入调查人员教授的课程。研究人员将针对跨流域物理模板的微生物功能特征分布的紧急特性以及对水文可变性的响应。该项目将对康涅狄格州、德舒特斯、甘尼森和威拉米特流域进行抽样，这些流域的大小相似，但气候和地貌不同。在每个流域内，抽样将侧重于不同大小的溪流、水库的影响和水文变异性。拟议的研究将开发数学表达式，将浮游微生物群落的发展和活动的多个指数与水流顺序、水流水力学(例如，流速和深度)、水流变异性和温度联系起来。这些指数将基于基因组多样性的元基因组学，基因表达的元转录组学，以及河流样品中微生物16S rRNA基因扩增子序列的系统发育多样性。微生物指数将与水柱微生物群落发展的时间尺度(即停留时间)和微生物转化率(例如反硝化)的模型化估计进行比较。据假设，地貌(如深度、流速)、流量变化和温度是河网水体中何时何地出现不同的浮游微生物河流群落的主要决定因素。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Rivers are the circulatory systems of the continents, delivering land-derived water, pollutants and elements to the ocean. They are also sites with unique organisms, food webs, and microbial communities that can transform these materials during transport to the ocean. Microbes are the engines for these transformations, with considerable capacity to remove or alter important elements (e.g., carbon, nitrogen, phosphorus, mercury, arsenic), produce greenhouse gasses, and support food webs. However, due to large changes in water flow from day to day, and the big differences in the types of streams and rivers across the landscape, understanding how riverine microbes impact the chemistry of rivers is difficult. This project will research a set of "Watershed Rules of Life" that govern the establishment of riverine water column microbial communities that are critical to understanding rivers as circulatory systems. The researchers have proposed a set of hypotheses that adds microbial ecology into the scaffolding of hydrology and geomorphology in order to research these Watershed Rules of Life. The hypothesis will be tested by field work and modeling in a diverse set of watersheds throughout the United States. The knowledge gained by these studies will allow for a broader understanding of rivers in both the U.S. and other temperate regions of the world. The investigators will interact with the Yale New Haven Promise Internship program, which provides internships for students from New Haven interested in STEM. Professor Raymond will also interact with students at the Crested Butte Community School. This project will train graduate and undergraduate students at UMass, OSU and Yale. Findings will be incorporated into courses taught by the investigators. The researchers will target the emergent property of microbial functional trait distributions across the physical templates of watersheds and in response to hydrologic variability. The project will sample the Connecticut, Deschutes, Gunnison and Willamette watersheds, which are similar in size but differ in climate and geomorphology. Within each watershed, sampling will focus on streams of different sizes, the impact of reservoirs and hydrologic variability. The proposed research will develop mathematical expressions that relate multiple indices for the development and activity of planktonic microbial communities to stream order, stream hydraulics (e.g., velocity and depth), flow variability, and temperature. These indices will be based on metagenomics for genomic diversity, metatranscriptomics for gene expression, and microbial 16S rRNA gene amplicon sequencing for phylogenetic diversity in riverine samples. Microbial indices will be compared to modeled estimates of the time scale for water column microbial community development (i.e., residence time) and microbial transformation rates (e.g., denitrification). It is hypothesized that geomorphology (e.g., depth, velocity), discharge variability, and temperature are the main determinants of when and where distinct planktonic microbial riverine communities emerge in the water column of river networks.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.