Biosignatures of microbial function in subsurface systems

地下系统微生物功能的生物特征

• 批准号: RGPIN-2014-04563
• 负责人: Slater, Greg
• 金额: $ 5.25万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=587883
• 关键词: Biosignatures; microbial; function; subsurface; systems

Microbial organisms were the first and remain the most prolific forms of life on Earth, and are thought to be the most likely form of life to be observed in the search for life beyond the Earth. Understanding the unique organic, isotopic, mineral or morphologic biosignatures associated with microbial life in extreme environments provides the foundation for our interpretation of the history of life on Earth recorded in the geologic record, as well as the basis by which we will search for life on Mars or elsewhere. While estimated to be comparable in mass to that on Earth’s surface, the subsurface biosphere is only recently being explored. This proposal seeks to understand the carbon sources, metabolic activities and biosignatures associated with life in the deep terrestrial subsurface, and to compare and contrast it with those of endolithic communities living just below the surface of rocks in extreme environments. Taking advantage of ongoing research and relationships with working mines, this research will sample fracture systems that range from paleometeoric, biological systems isolated for thousands to millions of years at shallower depths to ancient, deeper systems that have been isolated for up to more than a billion years and may preserved abiotic signatures comparable to the early Earth and meteorites. Biosignatures of bacteria, eukarya and archea, as well as signatures of bacterial spore formation will be analyzed across these systems to assess the microbial community including the distribution of microbial abundance, the carbon sources and cycling that is supporting it, and the limits on its persistence along with the extent to which it is a dynamic system over geologic timescales. Recognizing and interpreting evidence of the activities of microbial life, both on Earth and potentially beyond, also requires the ability to differentiate unique “biosignatures” of life and its processes from signatures of abiotic systems (“abiosignatures”). While life has overprinted any abiotic signatures in almost all environments on Earth, some of these deep fracture systems, especially the most ancient ones, may in fact sample abiotic conditions and thus provide an unparalleled opportunity to characterize “abiosignatures” on Earth. These abiosignatures could then be compared to those associated with meteorites and provide an exciting new perspective on the search for life beyond the Earth. In addition to field samples, microcosm experiments designed to characterize biosignatures of microbial utilization of energy and/or carbon sources generated via water rock interaction will be used generate an laboratory based dataset that will contribute to interpretation of field results. As a counter point to this deep subsurface system, a secondary research focus will be on endolithic communities living millimeters below the surface of rocks in surface environments under extremes of aridity, temperature and geochemistry. Understanding the abundance, metabolisms and persistence of these systems will contribute complimentary insight to the research in the deep subsurface, furthering our understanding of the limits and capabilities of life, as well as developing our understanding of biosignatures and their implications to the record of life in the geologic record of life on Earth and as targets for the search for life on other planets.

微生物是第一个，仍然是地球上最多产的生命形式，被认为是在地球以外的生活中观察到的最有可能观察到的生命形式。了解在极端环境中与微生物生活相关的独特有机，同位素，矿物或形态生物签名为我们解释地质记录中记录的地球生活历史的基础，以及我们将在火星或其他地方寻找生活的基础。虽然估计在地球表面上的质量是可比的，但直到最近才探索地下生物圈。该提议旨在了解与深层地下的生命相关的碳源，代谢活动和生物签名，并将其与生活在极端环境中岩石表面以下的内线石器时代社区的碳来源进行比较和对比。利用正在进行的研究和与工作地雷的关系，这项研究将采样裂缝系统，从隔离的古流动性，生物系统隔离到数千万到数百万年，到较浅的层次到古代，更深的系统，这些系统已被隔离了多达亿年，并且可能保留了与早期地球和地球早期和地球和象征相当的非生物签名。细菌，真核病和阿彻的生物签名以及细菌散射形成的特征将在这些系统中进行分析，以评估微生物群落，包括微生物丰度的分布，支持它的碳源和循环，以及其持久性的局限性以及它具有动态的地球系统的效果。认识和解释微生物生命活动的证据，无论是在地球上还是在范围内，都需要能够区分生命的独特“生物签名”及其过程与非生物系统的特征（“ Abiosignatures”）。尽管生命在地球上几乎所有环境中都过多地打印了任何非生物签名，但其中一些深层断裂系统，尤其是最古老的系统，实际上可能采样了非生物条件，因此提供了无与伦比的机会来表征地球上的“ Abiosignations”。然后可以将这些非生物结构与与陨石相关的结构进行比较，并为寻求地球以外的生命提供令人兴奋的新观点。除田间样品外，使用水岩相互作用生成的能量和/或碳源的微生物利用的生物签名旨在表征型缩影实验，将生成一个基于实验室的数据集，该数据集将有助于对现场结果的解释。作为对这个深处的地下系统的反对点，二级研究重点将集中在岩石表面以下在岩石表面以下的胚胎社区，在干燥，温度和地球化学的极端情况下。了解这些系统的丰度，新陈代谢和持久性将为深度地下的研究提供互补的见解，进一步了解我们对生命的局限性和能力的理解，以及对生物签名的理解及其对生物记录的理解及其对人地球生活记录中的生活记录的影响，以寻求生命的目标，以寻求其他人的生活。