Collaborative Research: The Role of Snow Patches on the Spatial Distribution of Soil Microbial Communities and Biogeochemical Cycling in the Antarctic Dry Valleys.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。一个模型提出，微生物普遍分布在全球环境中，环境条件选择生理适应当地物理条件的类群。另一种模型预测，扩散是微生物分布的重要限制，微生物群落的空间异质性是扩散和当地环境限制的结果。根据这两种模式，微生物群落的空间异质性可能在极端生态系统中特别明显，在极端生态系统中，具有合适生理学的生物体的环境选择是最明显的。我们认为南极陆地环境是研究微生物地理学的理想场所，原因有三：1）南极的原始性质和偏远性使通过人类媒介传播的外来物种的流行最小化; 2）南极环境的极端条件提供了一个强大的环境过滤器，限制了非土著类群的建立;陆地环境的极端异质性提供了土壤条件（温度、水和养分供应）的自然梯度。在拟议的研究中，我们将调查雪对土壤微生物群落的组成和空间分布的影响，并在麦克默多干旱山谷的土壤地球化学循环。我们将在景观尺度（重复遥感以表征雪的分布），在山谷和斑块尺度（量化雪斑块消融，微生物群落和亚表层土壤的地球化学循环）进行实地考察。我们假设，雪补丁在构建土壤微生物群落的空间分布及其相关的生态系统功能，因为物理和水文的影响，雪补丁对土壤环境中发挥了重要作用。这项研究将通过与国际南极研究所公共外联活动的直接联系，包括传播环境科学和微生物学网络学习单元，作为中学和中学后教育工作者的资源，帮助公众进一步认识极地研究对生物学、生态学和水文学等基本问题的重要性。三名研究生，一名博士后学者和多名本科生将参加研究活动。

AbstractThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Two models have been proposed to describe controls over microbial biogeography. One model proposes that microbes are ubiquitously distributed across the global environment, and that environmental conditions select for taxa physiologically adapted to local physical conditions. An alternative model predicts that dispersal is the important limitation to the distribution of microorganisms and that spatial heterogeneity of microbial communities is a result of both dispersal and local environmental limitations. According to both models, spatial heterogeneity of microbial communities may be especially pronounced in extreme ecosystems where the environmental selection for organisms with suitable physiology is most strongly manifest. We propose that Antarctic terrestrial environments are ideal places to examine microbial biogeography for 3 reasons: 1) the pristine nature and remoteness of Antarctica minimizes the prevalence of exotic species dispersed through human vectors; 2) the extreme conditions of Antarctic environments provide a strong environmental filter which limits the establishment of non-indigenous taxa; and 3) extreme heterogeneity in the terrestrial environment provides natural gradients of soil conditions (temperature, water and nutrient availability). In the proposed research we will investigate the influence of snow on the composition and spatial distribution of soil microbial communities and linked biogeochemical cycling in the McMurdo Dry Valleys. We will conduct fieldwork at the landscape scale (repeated remote sensing to characterize snow distribution), at the valley and patch scales (quantify snow patch ablation, microbial communities and biogeochemical cycling in subnivian soils). We hypothesize that snow patches play an important role in structuring the spatial distribution of soil microbial communities and their associated ecosystem functioning because of the physical and hydrological influences that snow patches have on the soil environment. The research will contribute to greater public awareness of the importance of polar research to fundamental questions of biology, ecology and hydrology through direct linkages with International Antarctic Institute public outreach activities, including dissemination of web-based learning units on environmental science and microbiology, targeted as resources for secondary and post-secondary educators. Three graduate students, one postdoctoral scholar and multiple undergraduates will participate in the research activities.