Controls on the Abundance of Carbon Species in Unsedimented Submarine Hydrothermal Systems: An Experimental Investigation

随着人们对热液在洋壳中大规模喷发和循环的范围和性质有了更多的了解，地下生物地球化学循环中非生物化学的界线在某些意义上变得越来越模糊，但在另一些意义上却明显交织在一起。目前，对水热流体中有机化合物化学的考虑提出了许多不确定因素和有趣的问题。这项研究的实验室实验方法将使用柔性槽水热容器来研究一些关键的化学目标：i)在与大洋玄武岩热液蚀变过程中经历的条件相适应的温度和压力下测量方解石的溶解度，ii)测定矿物催化的二氧化碳非生物还原为CH4的速率，以及iii)评估水的热力学活性对催化活性矿物在非生物形成还原碳化合物上的有效性的影响。对这些研究结果的解释涉及似乎各种各样的主题，如大洋中脊碳循环、过量二氧化碳的地质固定、极端环境中生命的存在，甚至它的起源。

ABSTRACTOCE-0136954As more is discovered of the extent and nature of the large scale venting and circulation of hydrothermal waters through the oceanic crust, delineation of abiotic chemistries from subsurface biogeochemical cycles has become increasingly blurred in some senses, yet clearly intertwined in others. Consideration of the chemistry of organic compounds in aqueous hydrothermal fluids currently poses many uncertainties and intriguing questions. The deliberately constrained laboratory experimental approach of this study will use flexible-cell hydrothermal vessels to investigate a number of key chemical objectives: i) measurement of calcite solubility at temperatures and pressures appropriate to the conditions experienced during the hydrothermal alteration of oceanic basalts, ii) determination the mineral catalyzed rates of abiotic reduction of CO2 to CH4 and iii) evaluation of the influence of the thermodynamic activity of water on the effectiveness of catalytically active minerals on the abiotic formation of reduced carbon compounds.Interpretation of the results of these investigations has impact upon topics as seemingly diverse as the mid-ocean ridge carbon cycle, the geological sequestration of excess carbon dioxide, the existence of life in extreme environments and even its origin.