Organic geochemical and isotopic analysis of dissolved and particulate organic matter of diffuse flow hydrothermal water (Juan de Fuca ridge; ODP Borehole Observatories)

越来越多的证据表明，存在大量的海底生物圈，其化学成分和相关的微生物活动在整个海底发生变化，特别是与洋中脊（MOR）环境有关，在那里，新的地壳物质沿着MOR侧翼形成并随着时间的推移而老化。虽然人们正在研究这些环境的许多方面，并建立了专门的观测站来检查这些环境中的生物和化学过程，但对这些环境中溶解和颗粒有机物的组成如何变化的研究和理解很少。对溶解和颗粒有机物质组成的详细检查，以及对MOR侧翼地下（基底）流体化合物“年龄”的同位素特征的检查，将为这些系统的生物地球化学提供急需的信息。目前的项目旨在利用国际海洋钻探计划（IODP）资助的现有设施来研究海底生物地球化学的这一方面。芝加哥伊利诺伊大学的研究人员将从Juan de Fuca Ridge的ODP钻孔天文台设施收集样本，并将与其他受资助的研究合作收集这些样本。这些样品将用于检测地壳老化和转变过程中溶解有机物和颗粒有机物（DOM和POM）的组成。这项研究将检查这些流体的有机地球化学性质，这些流体的年龄从50万年到350万年不等，温度从38°C到270°C不等。现有设施将允许收集未受污染的地下流体，对化学和同位素结果的解释将允许检查化学反应和微生物过程随着时间的推移对流体的影响。对样品的分析将与德国不来梅大学合作完成，由夏威夷大学和华盛顿大学的其他研究人员共同收集的样品将提供有关流体体积特性的详细信息，包括它们的体积有机特性。这项研究为已经在这里工作的微生物学家、无机和有机地球化学家组成的现有多学科研究团队增加了一个重要组成部分。本研究以有关基底生物圈生物地球化学的假设为指导。这些假设认为，脂质组成和DOM的整体组成反映了基底地壳温度、化学和水文条件下生物组合和群落结构的差异，低分子量有机物（LMOM）是微生物生产力的重要来源。进一步假设这些LMOM是通过化学和生物过程产生的。最后，假设海底过程是可能从基底地壳输出的硫化有机化合物的潜在重要来源。有机地球化学分析将包括脂质的特征以及碳同位素组成的测量。傅里叶变换-离子回旋共振-质谱（FT-ICR-MS）是一种非常强大的技术，可以解析DOM成分的复杂性质，并提供其确切元素组成的信息。这些数据将允许指纹识别。并允许检查DOM特征随时间的演变，这将有助于确定在这些环境中发生的相关生物地球化学过程。更广泛的影响：本研究的科学和社会影响涉及到理解海洋-上地壳环境中发生的复杂相互作用，这是一个生物地球化学重要性和高时空变异性的区域。这些相互作用影响化学物质进入深海，并影响海洋化学。拟议的研究将涉及伊利诺伊大学芝加哥分校的研究生和本科生，这是一个城市校园，大多数理工科学生来自代表性不足的群体。这些学生将被招募参加这个项目。首席研究员还将为“海上教师”项目做出贡献。并将在这些活动期间与教室里的学生进行电子互动。

There is growing evidence that a substantial sub-seafloor biosphere exists and that its chemical composition and associated microbial activity changes across the seafloor, especially in relation to mid-ocean ridge (MOR) environments, where new crustal material is formed and ages over time along the MOR flanks. While many aspects of these environments are being studied, and dedicated observatories have been established to examine the biological and chemical processes in such environments, there has been little study, and there is little understanding of how the composition of dissolved and particulate organic matter changes in these environments. A detailed examination of the composition of the dissolved and particulate organic material, and an examination of isotopic signatures of compound 'age' of the MOR flank subsurface (basement) fluids will provide much needed information on the biogeochemistry of these systems. The current project is designed to examine this aspect of sub-seafloor biogeochemistry using existing facilities funded through the International Ocean Drilling Program (IODP). Investigators from the University of Illinois at Chicago will collect samples from the ODP Borehole Observatory Facility that exists at the Juan de Fuca Ridge, and will collect these samples in collaboration with other funded studies. The samples will be used to examine the composition of dissolved and particulate organic matter (DOM and POM) during the aging and transformation of the crust. The study will examine the organic geochemical properties of the fluids that range in age from less than 0.5 to 3.5 million years, and temperatures from about 38° to 270°C. The existing facility will allow for the collection of uncontaminated subsurface fluids and the interpretation of the chemical and isotopic results will allow examination of the impacts of chemical reactions and microbial processes on the fluids over time. The analysis of samples will be completed in collaboration with the University of Bremen, Germany, and samples co-collected by other investigators from the Universities of Hawaii and Washington will provide details concerning the bulk characteristics of the fluids, including their bulk organic characteristics. This research is adding an important component to the existing multidisciplinary research team of microbiologists, inorganic and organic geochemists already working at this location.The research is guided by hypotheses relevant to the biogeochemistry of the basement biosphere. The hypotheses state that the lipid composition, and overall DOM composition, will reflect differences in biological assemblage and community structure, which depends on the temperature, chemistry, and hydrology of the basement crust, and that low molecular weight organic compounds (LMOM) are important sources of microbial productivity. It is further hypothesized that these LMOM are produced by both chemical and biological processes. Finally, it is hypothesized that the sub-seafloor processes are potentially important sources of sulfurized organic compounds that could be exported from the basement crust.The organic geochemical analyses will include characterization of lipids as well as measurement of carbon isotopic composition. Dissolved organic matter (DOM) of basement fluid and bottom seawater will be analyzed by Fourier Transform-Ion Cyclotron Resonance-Mass Spectrometry (FT-ICR-MS), a very powerful technique that can resolve the complex nature of the DOM constituents and provide information on their exact elemental composition. This data will allow ?fingerprinting? of the source materials and allow examination of the evolution of DOM characteristics over time, which will help identify the relevant biogeochemical processes occurring in these environments. Broader impacts: The scientific and societal impacts of this study relate to understanding the complex interactions that occur within the ocean-upper crust environment, a region of biogeochemical importance and high temporal and spatial variability. These interactions influence the inputs of chemicals to the deep ocean, and influence ocean chemistry. The proposed research will involve graduate and undergraduate students from the University of Illinois at Chicago, an urban campus with the majority of the science students being from under-represented groups. These students will be recruited for this project. The Principal Investigator will also contribute to the ?Teacher-at-Sea? outreach program at the University of Washington, and will interact electronically with students in the classrooms during these activities.