中文摘要：

生物多样性产生和维持机制长期以来是生态学研究的核心问题。人们通过实验观察和理论推导揭示了很多群落生物多样性的共有模式及其背后的生态学过程，而相关的工作主要集中在动植物等大型生物中。微生物是地球上数量最多、分布最广，以及在生态系统过程中发挥极其重要作用的生物类群，但人们对其群落多样性的认识还非常有限。将介绍目前人们对能够独立自由生活的微生物多样性分布模式的探索，总结对其背后的生物学利生念学过程的研究现状，并探讨当前面临的挑战。

英文摘要：

A central objective of ecology is to understand the mechanisms that generate and maintain biodiversity. Ecologists have conducted a lot of theoretical and empirical studies to unravel macroecological patterns of diversity and distribution of various organisms and to understand the underlying processes that produce these patterns. However, most of these studies focus on macroorganisms, i.e. plants and animals. While microorganisms are the most abundant and widespread on earth and mediate important ecosystem processes, little is known about their diversity and distributional patterns. Here, we review recent studies of the diversity pattern of free-living microorganisms and the potential underlying ecological processes, and then discuss some most challenging tasks in microbial diversity research.