Developing and Testing of Bioreactors for Methane Hydrate Biogeochemical Studies in the Laboratory

这项技术开发项目涉及甲烷水合物，这是地球上最丰富的碳氢化合物来源。几十年的地球化学研究证实了含有海洋沉积物的甲烷水合物中厌氧甲烷氧化(AMO)的重要性，但在碳循环中负责这一主要过程的微生物从未被分离出来，也没有获得能够净AMO的纯微生物培养。该项目需要一个跨学科的综合实验和现场计划，通过在受控的可变定义的实验室条件下跟踪AMO来确定AMO的机理，该实验室条件为微生物消费甲烷提供了一个热力学上有利的环境，而不是甲烷的生产。为了创造支持AMO的条件，将建造新设计的厌氧高压/低温生物反应器并进行测试。接种到生物反应器中的微生物将来自具有AMO活性的沉积物样本。这些沉积物将在俄勒冈州海岸外的卡斯卡迪亚边缘在原地条件下被回收。在生物反应器中进行浓缩期间，将对培养介质和产生的甲烷水合物进行各种地球化学分析，并将持续监测和表征环境的生物地球化学。生物反应器将为未来分析同位素标记的生物地球化学平衡和在明确控制条件下的动力学实验提供一个实验平台。

This technology development project addresses methane hydrates, which represent the most abundant hydrocarbon source on Earth. Decades of geochemical studies have established the importance of anaerobic methane oxidation (AMO) in methane hydrate containing marine sediments, but the organisms responsible for this major process in the Carbon cycle have never been isolated; and no pure cultures of microbes capable of net AMO have yet been obtained. The project entails an interdisciplinary integrated experimental and field program to determine the mechanism of AMO by following AMO under controlled variable-defined laboratory conditions that provide a thermodynamically favorable environment for microbial methane consumption over methane production. In order to create conditions which support AMO, newly designed anaerobic high pressure/low temperature bioreactors will be constructed and tested. The source of microorganisms inoculated into the bioreactors will come from sediment samples with AMO activity. These sediments will be recovered under in situ conditions from the Cascadia Margin off the Oregon coast. A variety of geochemical assays on the culture medium and the resulting methane hydrate will be performed during enrichments in the bioreactor, and the biogeochemistry of the environment will be continuously monitored and characterized. The bioreactors will provide an experimental platform for future analyses of isotopically labeled biogeochemical equilibrium and kinetic experiments under well defined controlled conditions.