Collaborative Research: Linking microbial diversity, gene expression, and the transformation of terrestrial organic matter in major U.S. rivers

合作研究：将美国主要河流的微生物多样性、基因表达和陆地有机质的转化联系起来

• 批准号: 1457794
• 负责人: Byron Crump
• 金额: $ 82.6万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457794&HistoricalAwards=false
• 关键词: Collaborative; Research; Linking; microbial; diversity

Rivers and streams are the major conduits for transporting of Earth's carbon from the land to the oceans. Much of the carbon is in a dissolved organic form, and it serves as food for aquatic microorganisms. The challenge is that the chemical diversity of dissolved organic carbon is very great, and the genetic diversity of aquatic microbes is also immense. Accordingly, this project will use state-of-the art genomic methods to study the diversity and specific functions of these microorganisms. The results will fill a critical gap in understanding the specific metabolic capabilities of these microbes and how they carry out the key ecosystem function of transforming and metabolizing highly complex, riverborne dissolved organic carbon. The data that will be collected are important for predicting the impacts of land-use change, nutrient use, and shifting climate on freshwater quality across the USA. The research involves a collaboration with the Yale Peabody Museum Evolution program for inner-city New Haven high-school students to train interns and develop an interactive museum exhibit on U.S. rivers. The project will also train a postdoctoral researcher, and undergraduate and graduate students, including members of underrepresented groups in science.The goal of the project is to describe interactions and feedbacks between watershed diversity, microbial functional diversity, and dissolved organic matter (DOM) chemistry in 36 large U.S. rivers, and to experimentally link gene expression with DOM degradation in five of them (the Altamaha, Columbia, Mississippi, St. Lawrence and Yukon). River sampling will be conducted in collaboration with a U.S. Geological Survey stream network. This research will address the concept that microbial genetic mechanisms in river ecosystems are closely linked to climate and landscape features that control river environmental conditions, particularly DOM quality. This concept implies that microbial function is shaped by DOM composition, climate, and river chemistry. These shaping forces alter the functional genetic capabilities required for competitive success within riverine microbial communities, and, thus, drive shifts in functional gene expression and phylogenetic composition, that, in turn, increase the efficiency of DOM metabolism and biogeochemical processes. Three hypotheses are to be tested: (1) the functional genetic composition and gene expression patterns of riverine microbial communities are correlated with the composition of riverine DOM; (2) community gene expression patterns vary predictably in response to shifts in the available forms of DOM; and, (3) the composition of riverine bacterial communities correlates with the composition of riverine DOM over space and time, and varies with watershed-specific climatic factors. The first hypothesis will be addressed with an empirical study of microbial community gene content (metagenomics), gene expression (metatranscriptomics), and DOM diversity (high-resolution analytical chemistry) during four seasons in five rivers that encompass a broad range of DOM composition. The second hypothesis will be addressed with an experimental study to identify active organisms and genes expressed by freshwater microbial metabolism. The third hypothesis will be addressed with an empirical study of microbes, DOM, and river chemistry in 36 major U.S. rivers. Statistical approaches being developed through a Microsoft-sponsored international working group (BioGeoChemistry Data System) will be applied to link microbial and DOM data.

河流和溪流是将地球碳从土地运输到海洋的主要渠道。 大部分碳都是溶解的有机形式，它是水生微生物的食物。 挑战在于，溶解有机碳的化学多样性非常出色，水生微生物的遗传多样性也很大。 因此，该项目将使用最先进的基因组方法来研究这些微生物的多样性和特定功能。 结果将填补了解这些微生物的特定代谢能力的关键空白，以及它们如何执行转化和代谢高度复杂的河流溶解有机碳的关键生态系统功能。 将收集的数据对于预测土地利用变化，养分使用以及气候对整个美国淡水质量的影响很重要。 这项研究涉及与耶鲁·皮博迪博物馆（Yale Peabody Museum Museum）的演化计划合作，为纽黑文高中生的学生培训实习生，并开发了在美国河流上的互动博物馆展览。 The project will also train a postdoctoral researcher, and undergraduate and graduate students, including members of underrepresented groups in science.The goal of the project is to describe interactions and feedbacks between watershed diversity, microbial functional diversity, and dissolved organic matter (DOM) chemistry in 36 large U.S. rivers, and to experimentally link gene expression with DOM degradation in five of them (the Altamaha, Columbia,密西西比州，圣劳伦斯和育空地区）。河流采样将与美国地质调查流网络合作进行。这项研究将解决以下概念：河流生态系统中的微生物遗传机制与控制河流环境条件（尤其是DOM质量）的气候和景观特征密切相关。这个概念意味着微生物功能是由DOM组成，气候和河流化学塑造的。这些塑造力改变了河流微生物群落中竞争成功所需的功能遗传能力，因此，功能基因表达和系统发育组成的驱动转移，从而提高了DOM代谢和生物地球化学过程的效率。要检验三个假设：（1）河流微生物群落的功能遗传组成和基因表达模式与河流DOM的组成相关； （2）社区基因表达模式随着DOM的可用形式的转移而有所不同； （3）河流细菌群落的组成与空间和时间上河流DOM的组成相关，并且与分水岭特定的气候因素不同。第一个假设将通过在五个河流中的四个赛季中的微生物群落基因含量（宏基因组学），基因表达（Metatranscriptomics）和DOM多样性（高分辨率分析化学）的经验研究来解决。第二个假设将通过一项实验研究来解决，以鉴定淡水微生物代谢表达的活性生物和基因。第三个假设将通过对36个主要河流的微生物，DOM和河流化学的实证研究来解决。通过Microsoft赞助的国际工作组（生物地球化学数据系统）开发的统计方法将应用于链接微生物和DOM数据。