Spatial Scaling of Bacterial Biodiversity

微生物构成了地球生物多样性的大部分，在生物地球化学循环和生态系统功能中发挥着关键作用，但人们对它们的空间分布知之甚少。历史上一直认为，由于其独特的生物学，自由生活的微生物在全球范围内无处不在，具有世界性，因此与其他形式的生命相比，具有根本不同的生物多样性比例关系。尽管这些差异被认为是微生物的普遍特征，但这方面的经验证据很少，最近的观察揭示了微生物生物多样性的比例关系，这种关系在性质上类似于植物和动物。这项研究建立在最近这些研究的基础上，以提供对微生物生物多样性的空间尺度的更全面的理解。该项目将使用贝塔多样性分析作为一种理论工具，回答有关扩散历史和环境异质性在控制微生物多样性空间尺度方面的相对重要性的问题。分析将基于一组空间上明确的微生物多样性数据，这些数据是由全球规模的采样计划生成的，重点是地中海地区的土壤-加州、智利、南非和澳大利亚的气候区域。微生物多样性将使用以甲烷氧化菌为重点的分子方法进行分析。统计分析将确定产生和维持微生物β多样性的过程的相对重要性，以及这些过程如何随区域、空间尺度和分类分辨率而变化。这项工作将有助于对全球生物多样性格局的总体理解。该项目的一个外展部分将吸引当地默塞德学区的学生参与一个促进将数学应用于环境科学的项目。

Microorganisms comprise much of Earth's biodiversity and play critical roles in biogeochemical cycling and ecosystem functioning, yet little is known about their spatial distribution. It has historically been assumed that due to their unique biology, free-living microorganisms are globally ubiquitous and cosmopolitan, and thus have fundamentally different biodiversity scaling relationships relative to those observed for other forms of life. Although these differences have been assumed to be universally characteristic of microorganisms, the empirical evidence for this is scant, and recent observations are revealing microbial biodiversity scaling relationships that are qualitatively similar to those of plants and animals. This research builds on these recent studies to provide a more comprehensive understanding of the spatial scaling of microbial biodiversity. This project will use beta-diversity analyses as a theoretical tool to answer questions about the relative importance of dispersal history and environmental heterogeneity in controlling the spatial scaling of microbial diversity. Analyses will be based on a spatially-explicit set of microbial diversity data, generated by a sampling scheme that is of global scale, and focused on soils in the Mediterranean-climate regions of California, Chile, South Africa, and Australia. Microbial diversity will be assayed using molecular methods focused on methane oxidizing bacteria. Statistical analyses will determine the relative importance of the processes generating and maintaining microbial beta diversity, and how these processes vary with region, spatial scale and taxonomic resolution. This work will contribute broadly to a general understanding of global biodiversity patterns. An outreach component of this project will engage students in the local Merced school district in a program that promotes the application of math to the environmental science.