DISSERTATION RESEARCH: Living on the Edge: Biodiversity and Metabolic Potential of Microbial Communities in Salt Crusts of the Hyperarid Atacama Desert

几十年来，阿塔卡马沙漠的极度干旱地区被认为是生命的干旱极限，环境太恶劣，无法维持任何生长。然而，最近发现微生物在土壤表面的盐结壳上定植。据推测，盐是它们生存的关键，因为它能够从大气中吸收水分，并在完全干燥的环境中形成液体溶液。该项目是对这一独特生态系统中微生物群落的第一次深入研究，旨在实现两个目标：1)分析微生物多样性如何受到水分有效性的影响，2)确定水分有效性的微小变化如何影响微生物群落的代谢潜力。这将通过使用16S rRNA基因测序、宏基因组分析和共聚焦激光扫描显微镜来完成。本研究探讨微生物多样性和代谢潜力如何随气候和湿度变化。研究结果将为描述地球上生命地理形态的生态学理论提供依据。这些理论对于生态系统的适当管理和预测生物对全球变化的反应至关重要。该研究的完成也将为未来探索微生物的干燥性和紫外线耐受性奠定重要的基础，这对包括生物技术和可再生能源在内的各个领域都有很大的兴趣。

For decades, the hyperarid region of the Atacama Desert was considered to be the dry limit to life, too hostile to sustain any growth. However, microorganisms have recently been discovered colonizing salt crusts on the surface of soils. It is hypothesized that salt is the key to their survival because it is able to absorb moisture from the atmosphere and create a liquid solution in an otherwise totally dry environment. This project is the first in-depth examination of the microbial communities in this unique ecosystem, and is designed to achieve two objectives: 1) to analyze how microbial biodiversity is affected by water availability, and 2) to determine how small changes in the availability of water influence the metabolic potential of the microbial communities. This will be accomplished through the use of 16S rRNA gene sequencing, metagenomic analysis, and confocal laser scanning microscopy. This research examines how microbial biodiversity and metabolic potential vary with climate and moisture. The results will inform ecological theories that describe geographical patterns of life on earth. These theories are essential for proper management of ecosystems and for predicting biological response to global changes. Completion of the proposed research will also lay critical groundwork for future exploration of the desiccation and UV tolerance of the microorganisms, which is of great interest to a variety of fields including, biotechnology and renewable energy.