Limits of Adaptation and Microbial Extinction in the Antarctic Desert

隐内生微生物在南极沙漠石灰岩的上几毫米处定居。这些微生物生活在极其极端的环境中，接近其生理潜能的绝对极限。融雪的水和光线穿透岩石，但生长似乎受到极低环境温度的限制。在麦克默多干谷的一系列地点观测到气候梯度。这项研究将量化环境条件。自动数据记录仪将监测岩石内部的微尺度气候，基于这些测量的计算机模型将有助于确定生命与灭绝之间的确切环境阈值。透射电子显微镜将用于记录死亡群落的退化和痕迹化石的形成。这里研究的群落被认为是早期火星生命最后阶段的陆地模型。这些研究的结果将有助于重建火星上的灭绝过程，并提出其目前的痕迹可能采取的形式。该项目由美国国家科学基金会和美国国家航空航天局联合资助。

Cryptoendolithic microorganisms colonize the upper few millimeters of limestone rocks of the Antarctic desert. These microbes live in a critically extreme environment, near the absolute limit of their physiological potential. Water from snowmelt and light penetrate the rocks but growth appears to be limited by the extreme low ambient temperatures. A climatic gradient has been observed to span a range of sites located in the McMurdo Dry Valleys. This study will quantify environmental conditions. Automatic data loggers will monitor the microscale climate inside rocks, and computer models based on these measurements will help identify the exact environmental threshold between life and extinction. Transmission electron microscopy will be used to document the degradation of dead communities and the formation of trace fossils. The communities studied here have been proposed as a terrestrial model for the last stages of life on early Mars. The results of these studies will serve to reconstruct the process of extinction on Mars and suggest the form its present- day traces might take. This project is jointly supported by the National Science Foundation and the National Aeronautics and Space Administration.