Biogeochemistry of Serpentinizing Systems

人为造成的二氧化碳（CO2）浓度正在上升。我们可以通过将其储存在地下的碳酸盐岩中来减少二氧化碳。二氧化碳可以在流经富含铁和镁、低硅和钾（超镁铁质）的岩石的地下水中自然转化为固体碳酸盐。这些反应被称为CO2的碳（C）矿化，它们与被称为蛇纹石化的过程有关。蛇纹石化是一种水-岩反应，产生具有非常高pH值的地下水，富含甲烷（CH 4）和氢（H2）。C矿化可能会增强注入CO2到地下水中的网站的蛇纹化。然而，地球化学碳循环和超镁铁质地下深部生物圈的了解甚少。我们不知道注入二氧化碳是否会导致甲烷的产生，这是另一种强大的温室气体。纯研究跟踪的C基板，转换，并在这个超镁铁系统的产品是必需的。此外，蛇纹岩化的地点可以在理解地球上生命的进化和极端环境中的生命方面发挥不可或缺的作用。蛇纹岩化的地点也对在其他超镁铁质行星和卫星上寻找生命感兴趣。因此，我正在进行的研究计划的3个长期目标是：1）量化大气和超镁铁质岩石之间的碳交换并增强碳储存; 2）确定生命如何在地下蛇纹化的高pH值，低营养极端环境中生存;和3）发现可用于确定地球和其他世界蛇纹化地点现存和生物化生命存在的生物特征。为了实现这些长期目标，在接下来的5年里，我将：1）量化自然CO2和CH 4通量，并确定如何增强蛇形化系统中的CO2封存; 2）确定活跃的微生物和病毒群落，以及蛇形化相关地下水中的代谢; 3）发现蛇形化地点过去和现在生活的分子和同位素指标。我预计这项研究将有助于：1）减缓气候变化的创新方法; 2）关于病毒和微生物鉴定，它们的相互作用以及碳的微生物代谢的新成果;和3）确定蛇纹石化的地点作为宇宙中其他地方极端微生物生命的可能场所，并作为太空探索的目标。除了为加拿大减缓气候变化和空间探索的方法作出贡献外，加拿大还将受益于对15名高素质人员的化学、生物和地质培训。

Anthropogenic carbon dioxide (CO2) concentrations are on the rise. We can reduce this CO2 by storing it in the ground as carbonate rock. CO2 can be naturally converted to solid carbonate in groundwaters flowing through rocks high in iron and magnesium and low in silica and potassium (ultramafic). These reactions are known as carbon (C) mineralization of CO2, and they are associated with the process known as serpentinization. Serpentinization is a water-rock reaction that produces groundwater with very high pH values and is enriched in methane (CH4) and hydrogen (H2). C mineralization may be enhanced by injecting CO2 into the groundwater at sites of serpentinization. However, the biogeochemical carbon cycling and the deep biosphere in the ultramafic subsurface are poorly understood. We do not know if injecting this CO2 may result in a greater production of CH4, which is another powerful greenhouse gas. Pure research in tracing the C substrates, transformations, and products in this ultramafic system is required. Additionally, sites of serpentinization could play an integral part in understanding the evolution of life on Earth and life in extreme environments. Sites of serpentinization are also of interest to the search for life on other ultramafic planets and moons. Thus, the 3 long-term goals of my ongoing research program are to: 1) quantify C exchange and enhance C storage between the atmosphere and ultramafic rocks; 2) determine how life survives in the high pH, low nutrient extreme environment of subsurface serpentinization; and 3) discover biosignatures that can be used to determine the presence of extant and fossilized life at sites of serpentinization on Earth and other worlds. To contribute to these long-term goals, over the next 5 years, I will: 1) quantify the natural CO2 and CH4 fluxes and determine how to enhance CO2 sequestration within serpentinizing systems; 2) determine the active microbial and viral communities, and the metabolisms within serpentinization-associated groundwaters; and 3) discover molecular and isotopic indicators of past and present life at sites of serpentinization. I anticipate this research will contribute to: 1) innovative methods for climate change mitigation; 2) novel outcomes with respect to viral and microbial identification, their interactions, and microbial metabolism of carbon; and 3) identification of sites of serpentinization as possible loci of extremophile life elsewhere in the universe, and as targets for space exploration. In addition to contributing to Canada's approach to climate change mitigation and space exploration, Canada will also benefit from the chemical, biological, and geological training of 15 highly qualified people.