Quantitative Investigation of Aqueous Organic Compounds in Ridge-Crest Hydrothermal Fluids

有机化合物在海洋中脊海水热液通过地壳的循环过程中起着重要的化学、物理和生物作用。尽管它们很重要，但目前尚不清楚沉积和非沉积轴向温泉系统热液中含水有机物质的丰度和组成。在这项研究中，将使用新设计的气密流体采样器和潜水器Alvin在Juan de Fuca山脊北部的Endeavour和Middle Valley热液区对热液流体进行采样。新的采样器允许在单个流体样品中定量地确定挥发性和非挥发性水性物质的丰度。流体将进行定量分析，以获得广泛的水性有机和无机物种，以充分表征地下化学环境，并限制有机-无机化学相互作用的程度。这些结果将使人们对热液系统中调节有机物种产生和破坏的因素有更多的了解，并允许对广泛的生物地球化学过程进行评估，如地壳蚀变、成矿金属的动员、从海洋地壳到水柱的碳通量、支持地下生物圈的营养物质的可用性，以及可能代表生命前体的有机化合物的非生物合成。

Organic compounds play an important role in numerous chemical, physical, and biological processes during circulation of seawater-derived hydrothermal fluids through the crust at mid-ocean ridges. Despite their importance, the abundance and composition of aqueous organic species in hydrothermal fluids from sedimented and unsedimented axial hot-spring systems are presently unknown. During this study, hydrothermal fluids will be sampled at the Endeavour and Middle Valley hydrothermal fields, northern Juan de Fuca ridge using a newly designed gas-tight fluid sampler and the submersible Alvin. The new sampler allows the abundance of both volatile and non-volatile aqueous species to be determined quantitatively in a single fluid sample. Fluids will be analyzed quantitatively for a broad spectrum of aqueous organic and inorganic species to fully characterize subsurface chemical environments and constrain the extent of organic-inorganic chemical interaction. The results will lead to an increased understanding of factors that regulate the generation and destruction of organic species in hydrothermal systems and allow evaluation of a broad spectrum of biogeochemical processes such as crustal alteration, mobilization of ore-forming metals, the flux of carbon from the oceanic crust to the water column, the availability of nutrients to support a subsurface biosphere, and the abiotic synthesis of organic compounds that may represent precursors to life.