Tolerance limits of methanogenic life in terrestrial permafrost

陆地永久冻土层产甲烷生命的耐受极限

• 批准号: 5418079
• 负责人: Professor Dr. Dirk Wagner
• 金额: --
• 依托单位: Department 3: Geochemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2007-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5418079?language=en
• 关键词: Tolerance; limits; methanogenic; life; terrestrial

The evolution of life on Earth had already started 3.8 Ga ago, when living conditions on Mars were similar to those on early Earth. Assuming that first life on both planets was determined by complex microbial communities, the Martian life must have adapted to drastically changing environmental conditions or become extinct again. One possibility for survival of Martian primitive life might be subsurface lithoautotrophic ecosystems. Comparable environments exist in permafrost regions on Earth. Thus, terrestrial permafrost is considered to be a model for extraterrestrial analogue studies. The main objective of the planed project is to study tolerance limits of lithoautotrophic microorganisms derived from Siberian permafrost. Beside nitrifying bacteria, which show various adaptation strategies, primarily methanogenic archaea will be used, which show specific adaptations to the oxygen and organic free environment of early Earth. Tolerances of microbes within natural soils as well as pure bacterial cultures will be tested with regard to different stress factors. The borders of growth influenced by temperature extremes, desiccation, starvation and increased salt concentrations will be analyzed. The comparative system studies will serve to understand the modern Mars cryosphere and other extraterrestrial permafrost habitats. This knowledge represents an essential basis for searching and understanding of extraterrestrial life, if present, especially concerning possible protected niches on present Mars.

地球上的生命进化在3.8 Ga前就已经开始了，当时火星上的生活条件与早期地球上的生活条件相似。假设这两颗行星上的第一个生命是由复杂的微生物群落决定的，火星生命必须适应急剧变化的环境条件，否则就会再次灭绝。火星原始生命生存的一种可能性可能是地下岩石自养生态系统。类似的环境存在于地球上的永久冻土区。因此，陆地永久冻土被认为是一个模型，为外星人的类似研究。该计划的主要目标是研究西伯利亚冻土中的岩石自养微生物的耐受极限。除了硝化细菌，它显示出各种适应策略，主要是产甲烷古菌将被使用，这显示出特定的适应早期地球的氧气和有机物的自由环境。将测试天然土壤中微生物以及纯细菌培养物对不同胁迫因素的耐受性。将分析受极端温度、干燥、饥饿和盐浓度增加影响的生长边界。比较系统研究将有助于了解现代火星冰冻圈和其他外星永久冻土栖息地。这些知识是搜寻和了解地外生命（如果存在的话）的重要基础，特别是关于目前火星上可能受到保护的生态位。