Chemolithotrophic life in ultramafic rocks: carbon substrates and pathways enabled by water-rock reactions using field and experimental hydrothermal investigations

在地球上最古老的岩石、陨石和其他行星的大气层中都发现了甲烷和其他碳氢化合物。在地球上，这些碳氢化合物通常被认为是生物活动的产物，因此可以指示今天或数十亿年前生命的存在。因此，碳氢化合物的研究对于研究早期地球上生命的起源和演化，以及在极端环境和其他行星上寻找生命具有重要意义。然而，碳氢化合物也可以由非生物(非生物)反应产生，但这些碳氢化合物的合成条件尚不清楚。为了区分生物成因碳氢化合物和非生物成因碳氢化合物，必须确定产生非生物成因碳氢化合物和反应抑制剂的地质条件。因此，必须为非生物成因碳氢化合物确定独特的地球化学指标。在自然环境中，识别非生物成因碳氢化合物的难度增加。地下水和其流经的岩石之间的反应，如蛇纹岩作用(超镁铁质岩石的水化作用)，为非生物成因碳氢化合物的生产和化学富含岩石的生命创造了可修改的条件。生物反应可以修改或叠印非生物起源的签名。因此，必须研究有利于非生物碳氢化合物生产和化学石质营养生命的地点的碳循环，以确定这些修饰，确定能够在蛇纹岩作用期间产生的极端pH条件下存活的生命，并确定这些系统中的生命对蛇纹岩作用产物的依赖。对超镁铁质岩石中早期生命和水-岩反应的研究将通过促进对地球生命演化和非生物成因碳氢化合物生产的认识而使加拿大人受益。

Methane and other hydrocarbons have been detected in Earth's oldest rocks, meteorites, and the atmospheres of other planets. On Earth, these hydrocarbons are often thought to be products of biological activities, and thus can indicate the presence of life today or billions of years ago. Therefore the investigation of hydrocarbons has implications for the study of the origin and evolution of life on early Earth, and the search for life in extreme environments and on other planets. Hydrocarbons, however, can also be produced by non-biological (abiogenic) reactions, yet the conditions under which these hydrocarbons are synthesized are not well understood. To differentiate between the biogenic and abiogenic hydrocarbons, the geologic conditions for creating abiogenic hydrocarbons and reaction inhibitors must be determined. Subsequently, unique geochemical indicators must be identified for abiogenic hydrocarbons. In natural settings, there is added difficulty identifying abiogenic hydrocarbons. Reactions between groundwater and the rock it flows through, such as serpentinization (the hydration of ultramafic rock), produce conditions amendable for abiogenic hydrocarbon production as well as chemolithotrophic life. Biological reactions can modify or overprint abiogenic signatures. Therefore, studying carbon cycling in locations favourable for abiogenic hydrocarbon production and chemolithotrophic life must be examined to determine these modifications, to identify life that can survive in extreme pH conditions that are created during serpentinization, and to determine the dependence of life in these systems on products of serpentinization. The research into early life and water-rock reactions in ultramafic rocks will benefit Canadians through the advancement of knowledge of life's evolution on Earth and the production of abiogenic hydrocarbons.