Experimental Study of Iron Partitioning and Hydrogen Generation During Serpentinization of Ultramafic Rocks

科学家们越来越意识到生活在海底和海底以下的微生物群落，它们依靠化学能（化学合成）而不是阳光茁壮成长。 虽然尚不清楚这种化学合成群落的丰富程度和分布范围，但有人认为，它们可能对全球生物量以及碳和其他元素的地球化学循环作出重大贡献。 维持这些深海微生物的化学能量的主要来源是分子氢（H2），它是由水与超镁铁质岩石反应产生的，这一过程被称为蛇纹石化。 然而，控制蛇纹石化过程中产生的氢量的因素仍然知之甚少。 本研究在高温和沿着水蒸气压曲线进行实验室实验，监测水-岩反应进行时的H2产生，作为模拟蛇纹石化过程的一种方法。 采用最先进的高分辨率方法对固体反应产物进行详细分析，可以确定产生氢气的化学反应。 数值地球化学模型将为将实验室结果外推到自然系统提供一个框架。这项工作的更广泛影响包括培训一名博士后助理和两名本科生。 这项研究还将成为一个新的大学课程的中心，该课程旨在培训学生采用多学科的科学方法。

Scientists have become increasingly aware of microbial communities living at and below the seafloor where they thrive on chemical energy (chemosynthesis) rather than sunlight. While it is not yet known how abundant and widespread such chemosynthetic communities are, it has been suggested that they may make significant contributions to global biomass and the biogeochemical cycles of carbon and other elements. A primary source of chemical energy that sustains these deep sea microbes is molecular hydrogen (H2), which is generated from the reaction of water with ultramafic rocks, a process known as serpentinization. However, the factors that control the amount of hydrogen generated during serpentinization remain poorly known. This research conducts laboratory experiments at high temperatures and along the vapor pressure curve of H2O that monitor H2 production as water-rock reactions proceed as a way to simulate the serpentinization process. Detailed analysis of the solid reaction products with state-of-the-art high resolution methods make it possible to define the chemical reactions that generate hydrogen. Numerical geochemical models will provide a framework for extrapolating the laboratory results to natural systems. Broader impacts of the work include training for a postdoctoral associate and two undergraduate students. The research will also serve as a focal point for a new university course aimed at training students in a multidisciplinary scientific approach.