Dimensions US-China-South Africa: Establishing genetic, phylogenetic and functional mechanisms that shape microbiome diversity of polar and alpine soils

微生物是生态系统的基础，并驱动土壤中的生物和化学，例如将土壤有机物质转化为温室气体二氧化碳和甲烷，以及可供植物使用的氮和磷化合物。土壤微生物群落多样性维持着生态系统的稳定性和可持续性。了解这些微生物的生态学是最引人注目的科学挑战之一。该项目将重点研究北极、南极和青藏高原土壤生态系统的微生物生态学。之所以选择这些“三极”土壤进行研究，是因为它们受气候变化的影响不成比例，预计未来将显示出微生物活动增加和土壤有机质周转增加。虽然微生物擅长适应环境变化，但微生物群落转变的功能影响仍有待确定。基于实验室和实地的方法将确定在这些“三极”土壤生态系统中成功的微生物及其原因，即，哪些细菌物种/菌株是成功的，以及哪些功能特性使它们成功。了解土壤生态系统如何在这些极地地区的反应是至关重要的评估控制的地球化学循环和澄清微生物反馈在不断变化的世界。该项目将组建一个国际团队，并招募年轻学者，以反映微生物学，生态学和环境科学方面的专业知识。研究将通过将样本和数据纳入K-12，本科生和研究生水平的实践课堂培训，与教育活动相结合。该项目将描述导致稳定和可持续土壤的标志性土壤微生物群落多样化的机制。我们缺乏对调节和维持微生物生物多样性的机制的预测性理解，以及这与微生物生物化学相关的微生物功能的关系。需要采取综合办法来确定形成和维持这种生物多样性的原则。该项目结合了生物多样性的遗传、系统发育和功能维度，以探索形成土壤系统“多样性沼泽”的因素。总体假设是，资源分配，选择性捕食，和时间分离的活动，每个有助于特定的细菌菌株/物种在极地和高山系统的成功。国际研究小组将专注于在北极，南极和青藏高原栖息地的土壤中测试这些假设，并将酸杆菌作为研究的模型微生物门。将结合实验室和现场方法来描述酸杆菌的遗传、系统发育和功能多样性，酸杆菌是在地球仪上发现的最普遍但最难以捉摸的细菌门之一。这项研究将确定它们在土壤中的生态系统功能，它们与其他微生物的相互作用，它们对气候变化等环境压力的适应，并将评估它们的原位动态和活动。这些数据的整合将解决哪些生物竞争资源，避免捕食，并最终在这些生态系统中占据根本不同的生态位。阐明这些平衡/稳定机制可以开始解释土壤微生物中观察到的巨大细菌多样性。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Microorganisms are the foundations of ecosystems and drive the biology and chemistry in soils, e.g. the conversion of soil organic matter into the greenhouse gases carbon dioxide and methane, as well as nitrogen and phosphorous compounds that can be used by plants. Soil microbial community diversity maintains ecosystem stability and sustainability. Understanding the ecology of these microorganisms is one of the most compelling scientific challenges. This project will focus on the microbial ecology of soil ecosystems in the Arctic, Antarctic, and Tibetan Plateau. These “tri-polar” soils are chosen for study as they are disproportionately impacted by climate change and predicted to show increased microbial activity and enhanced turnover of soil organic matter in the future. While microbes excel at adapting to environmental change, the functional implications of microbial community transitions remain to be characterized. Laboratory- and field-based approaches will identify microorganisms that are successful in these “tri-polar” soil ecosystems and why, i.e., which bacterial species/strains are successful and what functional traits make them successful. Understanding how soil ecosystems respond in these polar regions is critical for evaluating the controls of biogeochemical cycling and clarifying microbial feedbacks in a changing world. This project will assemble an international team and recruit young scholars to reflect a blend of expertise in microbiology, ecology and environmental sciences. Research will be integrated with educational activities by involving samples and data into hands-on classroom training at the K-12, undergraduate, and graduate levels.This project will delineate mechanisms that lead to diverse soil microbial communities that are hallmarks of stable and sustainable soils. We lack predictive understanding of mechanisms that regulate and maintain microbial biodiversity and how this relates to biogeochemically relevant microbial functions. Integrative approaches are needed to identify the principles that shape and maintain this biodiversity. This project combines genetic, phylogenetic, and functional dimensions of biodiversity to probe factors that shape the “morass of diversity” of soil systems. The overarching hypothesis is that resource partitioning, selective predation, and temporal separation of activity each contribute to the success of particular bacterial strains/species in polar and alpine systems. The international research team will focus on testing these hypotheses in soils across Arctic, Antarctic and Tibetan Plateau habitats with the Acidobacteria as a model microbial phylum for study. Laboratory- and field-based approaches will be linked to describe the genetic, phylogenetic and functional diversity the Acidobacteria, one of the most ubiquitous but elusive bacterial phyla found in terrestrial ecosystems around the globe. The study will identify their ecosystem functions in soils, their interactions with other microbes, their adaptations to environmental stress such as climate change, and will assess their in situ dynamics and activity. Integration of these data will address which organisms compete for resources, avoid predation, and ultimately, occupy fundamentally distinct niches in these ecosystems. Elucidating these equalizing/stabilizing mechanisms can begin to explain the tremendous bacterial diversity observed in soil microbiomes.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.