Sources of Organic Compounds in Submarine Hot-Springs: An Experimental Investigation

知识价值：热液喷口流体中的含水碳物种对海洋的碳通量、栖息在喷口环境中的生物群落和生命起源具有重要意义。虽然在热液流体中发现了几种有机化合物，但它们的来源是生物的还是非生物的尚不清楚。本研究使用高温高压下的实验室实验来评估这两个过程产生的有机组合的化学和同位素组成。这项工作的一个重点是纯气相费托反应（FT）的碳和氢同位素特征，这种非生物表面催化反应被用来解释自然环境中存在的生命前碳氢化合物。含水热解实验将在缓冲热液压力和温度条件下进行，使用三种类型的微生物生物量，利用海水溶解的有机碳，观察到高温热液流体中有机碳的浓度相对于海水有所下降。由此产生的同位素和成分数据将用于识别热液系统中迄今为止被忽视的潜在热解产物。更广泛的影响：这项研究支持博士后研究人员，并将吸引本科生参与研究。在pi的指导下，来自四年制公立大学布里奇沃特州立学院（Bridgewater State College）的一名本科生将密切参与实验设计过程和随后的分析工作，这一提议不需要任何费用。

Intellectual Merit: Aqueous carbon species in hydrothermal vent fluids have important implications for carbon fluxes to the ocean, biological communities that inhabit vent environments, and the origin of life. Although several organic compounds have been identified in hydrothermal fluids, their origin as either biotic or abiotic is unclear. This research uses laboratory experiments at high temperatures and elevated pressures to assess the chemical and isotopic composition of organic assemblages produced by these two processes. A focus of the work is the carbon and hydrogen isotopic signature of pure gas-phase Fischer-Tropsch type (FT) reactions, abiotic surface catalyzed reactions that have been invoked to explain the presence of pre-biotic hydrocarbons in natural environments. Hydrous pyrolysis experiments will be carried out at buffered hydrothermal pressure and temperature conditions using three types of microbial biomass using seawater dissolved organic carbon that is observed to have depleted concentrations in high-temperature hydrothermal fluids relative to seawater. Resulting isotopic and compositional data will be used to identify potential pyrolysis products in hydrothermal systems that have, to date, been overlooked. Broader Impacts: This research supports a postdoctoral researcher and will engage undergraduates in research. At no cost to this proposal, an undergraduate from Bridgewater State College, a four-year public undergraduate institution, will be intimately involved with the experimental design process and the subsequent analytical efforts, under mentorship by the PIs.