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首页> 外文期刊>Antarctic science >Effects of extreme cold and aridity on soils and habitability: McMurdo Dry Valleys as an analogue for the Mars Phoenix landing site
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Effects of extreme cold and aridity on soils and habitability: McMurdo Dry Valleys as an analogue for the Mars Phoenix landing site

机译：极端干旱和干旱对土壤和居住性的影响：麦克默多干旱谷作为火星凤凰登陆点的类似物

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AbstractThe McMurdo Dry Valleys are among the driest, coldest environments on Earth and are excellent analogues for the Martian northern plains. In preparation for the 2008 Phoenix Mars mission, we conducted an interdisciplinary investigation comparing the biological, mineralogical, chemical, and physical properties of wetter lower Taylor Valley (TV) soils to colder, drier University Valley (UV) soils. Our analyses were performed for each horizon from the surface to the ice table. In TV, clay-sized particle distribution and less abundant soluble salts both suggested vertical and possible horizontal transport by water, and microbial biomass was higher. Alteration of mica to short-order phyllosilicates suggested aqueous weathering. In UV, salts, clay-sized materials, and biomass were more abundant near the surface, suggesting minimal downward translocation by water. The presence of microorganisms in each horizon was established for the first time in an ultraxerous zone. Higher biomass numbers were seen near the surface and ice table, perhaps representing locally more clement environments. Currently, water activity is too low to support metabolism at the Phoenix site, but obliquity changes may produce higher temperatures and sufficient water activity to permit microbial growth, if the populations could survive long dormancy periods (～106 years).
机译：摘要麦克默多干旱谷是地球上最干燥，最冷的环境之一，是火星北部平原的绝佳类似物。为准备2008年凤凰火星计划，我们进行了跨学科研究，比较了泰勒河谷较低的较湿土壤（TV）与较干燥的大学谷地（UV）的生物学，矿物学，化学和物理性质。我们对从地表到冰台的每个地平线进行了分析。在电视中，黏土大小的颗粒分布和较少的可溶性盐都表明水的垂直和可能水平运输，微生物生物量更高。云母转变为短层状硅酸盐表明含水风化。在紫外线下，盐，粘土大小的物质和生物质在地表附近更为丰富，这表明水的向下迁移最少。首次在超干区建立了每个视野中微生物的存在。在地表和冰床附近发现了更高的生物量，这可能代表了当地更多的自然环境。目前，水的活动度太低，无法支持Phoenix地区的新陈代谢，但是如果种群可以长期休眠（约106年），倾斜的变化可能会产生更高的温度和足够的水活动性，从而使微生物得以生长。

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