LExEn: Water Stress Dynamics in Anhydrophilic Microbial Mats

生命存在和繁殖的最基本标准是水的存在。极端嗜热菌(嗜热菌、嗜热菌、嗜压菌、嗜酸菌、嗜盐菌、嗜碱性菌)只要有充足的水，就能在环境中活跃地定居和生长，尽管环境恶劣。相比之下，无水细胞对间歇性暴露在液态或气相水中，以及细胞成分缺乏水的单层覆盖的长期水分胁迫都表现出高度的耐受性。在这些条件下，电池还可能受到极端温度、太阳辐射和高盐度的影响。现存的厌水菌对急性干燥的生存和恢复反应可能为理解其他行星和卫星(即火星和欧罗巴)上可能存在各种形式水的生命过程的关键控制提供关键信息。这项研究将调查和描述微生物垫子的能力，这些微生物垫子被认为是地球上最早存在的生物群落的现代类似物，能够以干燥的形式在水分胁迫下生存下来。微生物垫是陆地和水生生态系统中无处不在、自我维持的特征，往往是地球上一些最极端(即温度、光照、养分枯竭)环境中唯一具有功能的生物群落。利用跨学科(生态学、生理学、分子生物学)和协作团队的方法，我们将确定在受全球气候梯度影响的极端环境中，从极地到温带到热带跃层，水资源可获得性和水分亏缺如何决定垫子群落的分布、活动和结构。这项研究的结果将适用于生态、分子和生物地球化学研究，目的是了解在缺水条件下基于发育、生存和进化的行星生命的极限。

The most fundamental criterion for the existence and proliferation of life is the presence of water. Extremophiles (thermophiles, pychrophiles, barophiles, acidophiles, halophiles, alkalphiles) can colonize and grow actively in environments, albeit harsh ones, as long as water is abundant. In contrast, anhydrophiles, exhibit a high tolerance for both intermittent exposure to liquid or gas-phase-water, and long term water stress where cellular components lack a monolayer coverage of water. Under these conditions cells may also be subjected to extremes of temperature, solar irradiation, and hypersalinity. The survival and recovery responses of extant anhydrophiles to acute desiccation may provides information critical to understanding key controls of life processes on other planets and moons where various forms of water may exist (i.e. Mars and Europa). This study will investigate and characterize the ability of microbial mats, which are believed to be modern day analogs of Earth's first extant biotic communities, to survive water stress in the form of desiccation. Microbial mats are ubiquitous, self-sustaining, features in terrestrial and aquatic ecosystems and are often the only functional biotic communities in some of the most extreme (i.e. temperature, irradiance, nutrient deplete) environments on Earth. Using an interdisciplinary (ecology, physiology, molecular biology) and collaborative team approach, we will determine how water availability and water deficit determine the distribution, activities and structure of mat communities in extreme environments subject to a global climatic gradient, ranging from polar to temperate to tropical clines. The results from this research will be applicable to ecological, molecular and biogeochemical studies aimed at understanding the limit of planetary life based on development, survival and evolution under water-deprived conditions.