Dissertation Research: Diversity, Distribution, and Cultivation of Novel Soil Bacteria from Snowmelt-Saturated Alpine Tundra

微生物的活动是全球营养循环的根本驱动力。然而，这些微生物中的绝大多数都是未经培养的，因此完全未知。研究新微生物的生物学对于了解它们在快速变化的生物圈中的功能、反应和反馈至关重要。土壤是微生物特别复杂的栖息地。它蕴藏着高度的微生物多样性和生物量，是研究的前沿，因为对其自然土壤环境中特定的新微生物的研究完全缺乏。这项拟议工作的目标是确定新发现的细菌在融雪淹没的高山冻原土壤中所起的作用。初步结果表明，这些细菌在地理上无处不在，位于耗尽氧气的土壤表面以下，但也普遍存在于冬季积雪的土壤表面。基于DNA序列的方法将被用来将这些新细菌的存在与各种环境特征联系起来。这种新型细菌预计将在寒冷、无氧的生境中茁壮成长，并将通过模拟这些条件而成为培养的目标。事实上，这项工作的一个主要目标是在实验室中分离出这种新的细菌。这项研究将首次深入了解特定的未培养的新型土壤细菌的生态学，并揭示无氧土壤区的范围和结构，这是养分循环中被忽视的因素。

The activity of microorganisms is the fundamental driver of global nutrient cycling. Yet, the vast majority of these microbes are uncultivated, and thus completely unknown. It is critical to investigate the biology of novel microbes to understand their function, response, and feedback on a rapidly changing biosphere. Soil is a particularly complex habitat for microbes. It harbors high microbial diversity and biomass, and is a frontier for research as studies of specific novel microbes within their natural soil environment are completely absent. The goal of the proposed work is to determine the roles of newly discovered bacteria from snowmelt-flooded alpine tundra soil. Preliminary results suggest that these bacteria are geographically ubiquitous, are located beneath the soil surface where oxygen is depleted, but are also prevalent at the soil surface under winter snowpack. DNA sequence-based approaches will be used to correlate the presence of these novel bacteria with various environmental characteristics. The novel bacteria are predicted to thrive in cold, oxygen-free habitats, and will be targeted for cultivation by mimicking these conditions. Indeed, a major goal of this work is to isolate the novel bacteria in the laboratory. This study will yield the first insights into the ecology of specific uncultivated, novel soil bacteria, and reveal the extent and structure of oxygen-free soil zones, an overlooked factor in nutrient cycling.