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

漫流热水中溶解有机物和颗粒有机物的有机地球化学和同位素分析（Juan de Fuca 海脊；ODP 钻孔观测站）

• 批准号: 1030681
• 负责人: Fabien Kenig
• 金额: $ 19.61万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1030681&HistoricalAwards=false
• 关键词: Organic; geochemical; isotopic; analysis; dissolved

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.

越来越多的证据表明，存在着大量的海底下生物圈，其化学成分和相关的微生物活动在整个海底发生变化，特别是在大洋中脊环境中，在那里，新的地壳物质沿着大洋中莫尔侧翼形成并随着时间的推移而老化。虽然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，但研究很少，对这些环境中溶解和颗粒有机物的组成如何变化的了解也很少。详细检查溶解和颗粒有机物质的组成，以及检查莫尔侧翼地下（基底）流体的化合物“年龄”的同位素特征，将提供这些系统的地球化学方面急需的信息。目前的项目旨在利用国际大洋钻探计划（IODP）资助的现有设施，研究海底下生物地球化学的这一方面。来自伊利诺伊大学芝加哥分校的调查人员将从胡安·德富卡海岭的ODP钻孔观测设施收集样本，并将与其他资助的研究合作收集这些样本。这些样品将用于检查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。该研究将检查年龄从不到50万年到350万年，温度从38°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对流体的长期影响。将与德国的不莱梅大学合作完成样品分析，来自夏威夷大学和华盛顿大学的其他研究人员共同采集的样品将提供有关流体整体特性的详细信息，包括其整体有机特性。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小组增加了一个重要组成部分，这项研究以与基底生物圈地球化学有关的假设为指导。该假说指出，脂质成分，和整体DOM组成，将反映生物组合和社区结构，这取决于温度，化学和水文的基底地壳的差异，和低分子量有机化合物（LIFE）是微生物生产力的重要来源。进一步假设，这些脂质是由化学和生物过程产生的。最后，假设海底下的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类的表征以及碳同位素组成的测量。基底流体和底层海水的溶解有机物（DOM）将通过傅立叶变换离子回旋共振质谱（FT-ICR-MS）进行分析，这是一种非常强大的技术，可以解决DOM成分的复杂性，并提供有关其确切元素组成的信息。这些数据将允许？指纹吗的源材料，并允许检查DOM特性随时间的演变，这将有助于确定在这些环境中发生的相关地球化学过程。更广泛的影响：这项研究的科学和社会影响涉及了解海洋-上地壳环境内发生的复杂相互作用，这是一个具有地球化学重要性和时空变异性的区域。这些相互作用影响着化学品进入深海，并影响着海洋化学。拟议中的研究将涉及来自芝加哥伊利诺伊大学的研究生和本科生，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。这些学生将被招募参加这个项目。主要研究者也将参与？海上教师？在华盛顿大学的推广计划，并将在这些活动中与学生在教室里进行电子互动。