CAREER: An integrated study of the effects of nutrient additions on grassland soil microbial communities

职业：养分添加对草原土壤微生物群落影响的综合研究

• 批准号: 0953331
• 负责人: Noah Fierer
• 金额: $ 65.56万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0953331&HistoricalAwards=false
• 关键词: CAREER; integrated; study; effects; nutrient

Terrestrial ecosystems across the globe are receiving elevated inputs of nitrogen (N) and phosphorus (P) due to human activities. The microbes that live in soil are likely to respond to these elevated nutrient inputs and such responses could have far-reaching effects on ecosystems given that soil microbes play critical roles in the maintenance of ecosystem health and productivity. However, how the overall structure and diversity of microbial communities may be altered by nutrient additions, and whether microbial responses mirror plant responses, are not yet known. To address these knowledge gaps, soils will be collected from 35 grasslands throughout the world that have been receiving standardized, experimental additions of N and P. The microbial and plant responses to nutrient additions across these grasslands that represent a broad range of soil and site characteristics will be compared to build a more comprehensive understanding of microbial responses to nutrient additions than would be possible by focusing on just a single site or a handful of sites. A series of laboratory experiments to discern the specific mechanisms that may be responsible for the microbial responses observed in the field will also be conducted.The proposed work is innovative in that it takes advantage of recently-developed pyrosequencing methods and phylogeny-based community analysis approaches to yield a far more comprehensive inquiry into soil microbial responses to nutrient additions than any previous study. Results of this study will lead to a predictive, mechanistic understanding of soil microbial responses to changes in nutrient availability and it will improve fundamental understanding of the factors structuring belowground microbial communities in grassland ecosystems. Since grasslands are one of the most widespread and productive ecosystem types on Earth, understanding how the structure and function of grasslands may change in response to elevated loadings of N and P from human activities (namely fossil fuel combustion and the use of agricultural fertilizers) is of critical importance. Better understanding of how microbes will respond to these nutrient inputs is needed because soil microbes play key roles in the maintenance of soil fertility, the terrestrial carbon cycle, and the overall health of ecosystems. The results, methods, and concepts to be developed from this work will be communicated and investigated through several key educational and outreach activities. (1) The initiation of a "hands-on", 2-week summer training course for U.S. and international graduate students focused on the use of molecular methods to assess soil microbial diversity. The course will provide a comprehensive introduction to the tools and approaches used to survey microbial biodiversity while fostering collaborations among the next generation of researchers inside and outside of the United States. (2) The development of a series of 'soil ecology' learning activities to introduce local middle-school students participating in the after-school Math, Engineering, and Science Achievement (MESA) program for students underrepresented in science and technology careers to the diversity of belowground biota and the importance of soil organisms in ecosystems. (3) The mentoring and training of graduate and undergraduate students who will be directly involved in the research project over the next 5 years.

由于人类活动，全球陆地生态系统正在接受氮（N）和磷（P）的投入升高。生活在土壤中的微生物可能会对这些养分升高的投入做出反应，并且这种反应可能对生态系统产生深远的影响，因为土壤微生物在维持生态系统健康和生产力方面起着关键作用。但是，尚不清楚微生物群落的整体结构和多样性如何改变营养素，以及微生物反应是否反映植物反应。为了解决这些知识差距，将从世界各地的35个草地中收集土壤，这些草原已接受了N和P的标准化，实验性添加。微生物和植物对这些草地中养分添加的反应，这些草地代表了代表土壤和现场特征的广泛范围的养分，而与对营养相比，将对营养添加更全面的理解是相比，与单个站点相比，将是对营养添加的更全面的理解。还将进行一系列实验室实验，以辨别在现场观察到的微生物反应的具体机制。拟议的工作具有创新性，因为它利用了最近开发的焦磷酸测序方法和基于系统发育的社区分析方法，以比以前对任何营养量更全面地探究。这项研究的结果将导致对土壤微生物对养分可用性变化的反应的预测性，机械理解，并将提高对草原生态系统中地下微生物群落的因素的基本理解。由于草原是地球上最广泛，最有生产力的生态系统类型之一，因此了解草原的结构和功能可能会因人类活动（即化石燃料燃烧和农业肥料的使用）的升高而变化，这是至关重要的。需要更好地了解微生物如何应对这些养分输入，因为土壤微生物在维持土壤生育能力，陆生碳循环和生态系统的整体健康方面起着关键作用。从这项工作中开发的结果，方法和概念将通过几项关键的教育和外展活动进行传达和研究。 （1）针对美国和国际研究生的“动手”，为期2周的夏季培训课程，重点是使用分子方法来评估土壤微生物多样性。该课程将为调查微生物生物多样性的工具和方法提供全面的介绍，同时促进美国境内和外部研究人员之间的合作。 （2）开发一系列“土壤生态学”学习活动，以介绍参与课后数学，工程和科学成就（MESA）计划的本地中学学生（针对科学和技术职业中缺乏代表性的学生的多样性）的多样性以及生态系统中土壤生物的重要性。 （3）将在未来5年中直接参与研究项目的研究生和本科生的指导和培训。