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，存在大量的海底下生物圈，其化学成分和相关微生物活动在整个海底发生变化，特别是与大洋中脊环境有关，在那里新的地壳物质沿大洋中脊侧翼形成并随着时间的推移而老化。虽然正在对这些环境的许多方面进行研究，并建立了专门的观测站来研究这些环境中的生物和化学过程，但很少有研究，对这些环境中溶解和颗粒有机物的组成如何变化也知之甚少。对溶解和颗粒有机物质的组成进行详细检查，并对MOR侧翼地下(基底)流体的化合物“年龄”的同位素特征进行检查，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由国际大洋钻探方案(大洋钻探方案)资助的现有设施，审查海底以下生物地球化学的这一方面。伊利诺伊大学芝加哥分校的研究人员将从胡安·德富卡山脊的ODP型钻孔观测站收集样本，并将与其他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化过程中溶解和颗粒有机物(DOM和POM)的组成。这项研究将检查年龄从不到50万年到350万年，温度从大约38°C到270°C的流体的有机地球化学性质。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。样品的分析将与德国不来梅大学合作完成，夏威夷大学和华盛顿大学的其他调查人员共同收集的样品将提供有关流体整体特征的细节，包括它们的整体有机特征。这项研究为已经在该地点工作的微生物学家、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。这项研究以与基底生物圈生物地球化学有关的假设为指导。这些假设指出，脂质组成和总体DOM组成将反映生物组合和群落结构的差异，这取决于基壳的温度、化学和水文，低分子量有机化合物(LMOM)是微生物生产力的重要来源。进一步假设，这些LMOM是由化学和生物过程产生的。最后，假设海底以下过程可能是可能从基底地壳输出的硫化有机化合物的重要来源。有机地球化学分析将包括脂类的表征以及碳同位素组成的测量。利用傅里叶变换-离子回旋共振-质谱仪(FT-ICR-MS)对基底流体和底层海水中的溶解有机物(DOM)进行分析，这是一种非常强大的技术，可以解决DOM组成的复杂性，并提供有关其准确元素组成的信息。这些数据可以用来识别指纹吗？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：这项研究的科学和社会影响涉及理解海洋-上地壳环境内发生的复杂相互作用，这是一个具有生物地球化学重要性和高度时空变异性的区域。这些相互作用影响了化学品对深海的输入，并影响了海洋化学。这项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，大多数理科学生来自代表性不足的群体。这些学生将被招募到这个项目中。首席调查员还将为海上教师？在华盛顿大学的外展计划，并将在这些活动期间在教室里与学生进行电子互动。

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.