Microbial Distributions in North American Biological Soil Crusts: Exploring the Great Divide

生物土壤结皮是在干旱地区普遍存在的表层土壤微生物有机沉积组合，那里的缺水限制了更高植被覆盖率的发展。这项研究将建立在先前对北美土壤结皮微生物生物多样性调查的基础上，包括莫哈德和奇瓦瓦沙漠地区。有了这些数据的补充，就可以检验这样一种假设，即热沙漠和冷沙漠之间的微生物分布存在巨大的生物地理差异。研究活动将包括尝试将已检测到但尚未研究的各种微生物带入培养。在所有方法中，将结合使用以DNA为基础的方法和传统的微生物学和系统技术。持续努力清点和描述土壤结皮的微生物种群，对于了解整个沙漠的生物地球化学功能并在面临越来越多的人为干扰时保护它们至关重要。这些努力可能会加强干旱土地生态系统的管理和保护。由于试错法不适用于土壤结皮等天生生长缓慢的生态系统，解释和预测能力必须依赖于对这些生态系统的环境限制和功能特性的彻底机械理解，而这在很大程度上取决于维持这些生态系统的微生物多样性的现有清单。

Biological soil crusts are topsoil organo-sedimentary assemblages of microorganisms that are prevalent in arid lands, where the lack of water restricts the development of much higher plant cover. This study will build on a previous survey of microbial biodiversity in North American soil crusts by including the Mohave and Chihuahuan desert regions. With the addition of these data the hypothesis that there exists a great biogeographical divide in the distribution of microbes between hot and cold deserts can be tested. Research activities will include attempts to bring into culture a variety of microorganisms that have been detected but not yet studied. In all approaches, a combination of DNA-based methodologies and traditional microbiological and systematic techniques will be used. A sustained effort in inventorying and describing microbial populations of soil crusts is crucial in order to understand the biogeochemical functions of deserts at large, and to safeguard them in the face of ever increasing anthropogenic disturbances. These efforts will likely enhance management and preservation of arid land ecosystems. Because the trial and error approach is not appropriate for ecosystems that are inherently slow-growing, such as soil crusts, explanatory and predictive abilities have to rely on a thorough mechanistic understanding of the environmental constraints and functional properties of these ecosystems, which hinges heavily on available inventories of the microbial diversity that sustains them.