Microbial Observatories: Anhydrophilic, Halotolerant Microbial Mats of San Salvador Island, Bahamas

Drs。Hans Paerl和Timothy Steppe（北卡罗来纳大学教堂山分校），Alan Decho（南卡罗莱纳大学哥伦比亚分校），James Pinckney（德克萨斯农工大学）正在研究位于巴哈马圣萨尔瓦多岛湖泊中高度多样化的微生物垫的群落结构和功能。由于圣萨尔瓦多的蒸发水量超过了降雨量，湖水的盐度可以达到正常海水的五倍。降雨的年际和季节变化使湖泊水位和盐度波动很大。因此，覆盖湖底大部分并控制湖泊生态的微生物席长期受到严酷的、可能致命的限制，如干燥、强烈的太阳辐射和高温。然而，它们设法在地球上一些最极端的条件下生长和生存。本研究的目的是评估5年期间水分供应对微生物垫结构多样化、群落组成、产量和碳固存的影响。特别强调的是培养和描述适应缺水环境的新型生物。将采用先进的分子生物学、高分子化学、生理学和微生物学技术来完成研究目标。水是生命不可缺少的。这项提议的工作解决了一个对所有生命都至关重要的基本机制，即保存水和平衡离子的能力。了解和描述缺水的微生物群落可能为理解可能存在水的其他行星和卫星上生命过程的关键控制提供至关重要的信息。无亲水性群落存在于“丰饶或饥荒”的条件下。圣萨尔瓦多的降雨是断断续续的，主要限于大风暴，包括该岛经常遭受的飓风。监测原始无水群落在不同水文条件下随时间的生理反应，将提供必要的信息，以了解长期和短期气候振荡（包括预测的10至40年飓风活动周期升高）如何影响关键的生命维持过程。培养个体种群将为了解可用于工业或医疗目的的无水生命形式的生物学提供具体信息。

Drs. Hans Paerl and Timothy Steppe (University of North Carolina at Chapel Hill), Alan Decho (University of South Carolina at Columbia), James Pinckney (Texas A & M University) are examining the community structure and function of highly-diverse microbial mats located in lakes on San Salvador Island, Bahamas. Because water evaporation exceeds rain precipitation on San Salvador, lakewater salinity can reach up to five times that of normal seawater. Interannual and seasonal variability in rainfall causes lake-levels and salinities to fluctuate greatly. Consequently, the microbial mats, which cover extensive portions of the lake bottoms and control the lakes' ecology, are subjected to prolonged periods of harsh, potentially lethal constraints such as desiccation, intense solar radiation, and high temperatures. Yet, they manage to grow and survive under some of the most extreme conditions on the planet. The objective of this study is to assess the influence water availability has on the structural diversification, community composition, production, and carbon sequestration in microbial mats over a five-year period. A particular emphasis will be placed on culturing and characterizing novel organisms that are adapted to water-stressed environments. State of the art molecular biological, polymer chemistry, physiological, and microbiological techniques will be employed to accomplish the research goals.Water is indispensable for life. The proposed work addresses a fundamental mechanism that is essential to all life, the ability to conserve water and balance ions. Understanding and characterizing water-stressed microbial communities may provide information crucial for understanding key controls of life processes on other planets and moons where water may exist. Anhydrophilic communities exist under 'feast or famine' conditions with regard to water availability. Rainfall on San Salvador is episodic and largely confined to major storms, including hurricanes to which the island is often subjected. Monitoring the physiological responses of pristine anhydrophilic communities over time and under different hydrologic conditions will provide information necessary to understanding how long and short term climatic oscillations (including a predicted 10 to 40 year period of elevated hurricane activity) impact critical life-sustaining processes. Culturing individual populations will provide specific information for understanding the biology of anhydrophilic life forms that may be exploited for industrial or medical purposes.