Collaborative Research: Experimental controls on Clumped Isotope Signatures of Methane in Deep-Sea Vents

该项目将研究海洋热液系统中甲烷气体化学特性的控制。该项目将使用实验室实验来探索甲烷气体和二氧化碳的同位素组成。这些实验室数据将使未来对海底喷口中的CH4和CO2的研究成为可能。这项研究将为地球内部和海洋之间碳循环的研究提供信息。它也与极端环境下的生命和生命的起源有关。项目更广泛的影响包括研究生和本科生以及高中暑期实习生的研究机会。来自加州州立大学圣贝纳迪诺分校（一所少数族裔服务机构）的研究生将在马里兰大学和华盛顿卡内基研究所学习。在那里，他们将获得最先进的同位素地球化学经验。深海热液喷口系统通过将热源、非生物和微生物来源的有机化合物引入上覆水柱，影响地球内部和海洋之间的碳循环。玄武岩和超镁铁质热液系统的喷口流体除含有丰富的CH4外，还含有其他有机物质。本项目旨在利用双取代双氘同位素（13CH3D, 12CH2D2）研究深海喷口CH4的成因和演化。在一系列涉及有机物分解的热液实验中。利用高质量分辨率气源多收集器质谱仪（Panorama， UMD）评估稀有甲烷同位素物的分布。实验将评估12CH2D2-13CH3D-12CH3D-12CH4-13CH4-HD-HDO-H2O体系中的平衡关系，并描述与矿物相和H2O H同位素组成对非生物和热成因形成机制的影响相关的同位素效应。本研究旨在将三角洲- 12ch2d2和三角洲- 13ch3d的演化应用于海底热液系统和海洋地壳深处的水/岩相互作用进行综合研究。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The project will study the controls on the chemical characteristics of methane gas in ocean hydrothermal systems. This project will use laboratory experiments to explore the isotopic composition of methane gas and carbon dioxide. Those lab data will enable future studies of CH4 and CO2 in seafloor vents. The study will inform studies of the cycling of carbon between the Earth’s interior and oceans. It is also relevant to life in extreme environments and the origin of life. Project broader impacts include research opportunities for graduate and undergraduate students and high-school summer interns. Graduate students from California State University, San Bernardino (a minority-serving institution) will spend time at the University of Maryland and the Carnegie Institution of Washington. There they will gain experience with state-of-the-art isotope geochemistry.Deep-sea hydrothermal vent systems affect the cycling of carbon between the Earth’s interior and oceans by introducing organic compounds of thermogenic, abiotic and microbial origin to the overlying water column. Vent fluids from both basalt and ultramafic-hosted hydrothermal systems contain abundant CH4 in addition to other organic species. This project aims to explore the origin and evolution of CH4 in deep-sea vents by employing the use of double-substituted and doubly-deuterated isotopologues (13CH3D, 12CH2D2). In a series of hydrothermal experiments involving organic matter decomposition. CO2 reduction and non-equilibrated CH4 gases in the presence of mineral catalysts, the distribution of rare methane isotopologue will be assessed by the use of a high-mass-resolution gas-source multiple collector mass spectrometer (Panorama, UMD). Experiments will assess the equilibrium relationships in the 12CH2D2-13CH3D-12CH3D-12CH4-13CH4-HD-HDO-H2O system and describe isotope effects associated with the impact of mineral phases and H2O H isotope composition on the abiotic and thermogenic formation mechanisms. This study aims to be a comprehensive study of Delta-12CH2D2 and Delta-13CH3D evolution applied to subseafloor hydrothermal systems and water/rock interactions deeper in the oceanic crust.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.