The role of microbial Fe and Mn oxidation in submarine weathering of volcanic glass

来自加利福尼亚斯克里普斯海洋学研究所的研究人员将描述海底玄武岩表面化学的变化，特别是铁和锰的释放和氧化速率，这是由微生物与火山玻璃相互作用引起的。本研究主要解决以下问题：(1)玄武岩玻璃是否支持深海环境中化学岩石自养细菌的生长；(2)玄武岩玻璃的组成如何影响微生物群落组成、玻璃蚀变速率和二次相的形成；(3)Fe(II)-和Mn(II)-氧化细菌是否参与或加速玄武岩玻璃的蚀变。这项工作的主要目的是确定微生物的活动是否显著加速了海洋环境中玄武岩玻璃的溶解速率。这项工作的动机来自于玄武岩玻璃是海洋地壳中最丰富和最活跃的成分之一。科学计划将包括现场和实验室两个部分。实地调查将包括NOAA/NURP资助的潜水器在夏威夷和Loihi海山的侧翼潜水，研究最近的熔岩流，并进行为期一到五年的暴露实验。采样区域将包括那些具有铁（II）或锰（II）浓度范围的玻璃。实验室研究将模拟受控化学条件下玻璃的生物腐蚀。该分析项目将使用研究小组开发的新型同步加速器x射线分析技术，研究表面化学和Fe和Mn浸出和氧化深度的变化。将研究由玻璃定殖细菌生长的生物膜以及生长在玻璃上的微生物群落的多样性和组成。将使用最先进的分子生物学技术（FISH， TRFLP）对来自海底玄武岩的天然和实验室培养的铁和锰氧化微生物进行表征。风化玄武岩的地球化学分析将包括电子探针和配备能量色散化学分析仪的扫描电子显微镜的检查。这项工作将回答微生物是否导致火山玻璃的风化以及这一过程是否实质性地影响海洋中的生物地球化学循环的问题。它还将确定火山玻璃是否可以作为支撑深海地壳生命的可行基质。更广泛的影响包括开发和改进新的表面分析技术，支持和培训博士后学者和博士生。它还将通过互联网数据库和网站为高中/初中教师和学生提供数据和研究资源。

Researchers from the Scripps Institution of Oceanography in California will characterize changes in surface chemistry of seafloor basalts, in particular the rate of Fe and Mn release and oxidation, arising from microbial interaction with volcanic glasses. The research addresses the following questions: (1) do basaltic glasses support growth of chemolithoautotrophic bacteria in deep ocean environments, (2) how does the composition of the basaltic glass affect the microbial community composition, rates of glass alteration, and the formation of secondary phases, and (3) do Fe(II)- and Mn(II)-oxidizing bacteria participate in or accelerate the alteration of basaltic glass. The main goal of this work is to determine if the activity of microorganisms significantly accelerates the rates of basaltic glass dissolution in the marine environment. Motivation for this work comes from the fact that basaltic glass is one of the most abundant and reactive components of the ocean crust. The scientific program will include both field and laboratory components. Field investigations will include NOAA/NURP funded submersible dives on the flanks of Hawaii and Loihi seamount to study recent lava flows and carry out exposure experiments that will range from one to five years in duration. Sampling areas will include those with glasses that possess a range of Fe(II) or Mn(II) concentrations. Laboratory investigations will simulate biocorrosion of glass under controlled chemical conditions. The analytical program will entail investigation of changes in surface chemistry and in depths of Fe and Mn leaching and oxidation using novel synchrotron X-ray based analytical techniques developed by the research team. Biofilms grown by glass-colonizing bacteria will be studied as well as the diversity and composition of microbial communities growing on the glass. Characterization of natural and laboratory-grown Fe and Mn oxidizing microbes from sea floor basalts will be carried out using state-of-the-art molecular biological techniques (FISH, TRFLP). Geochemical analyses of weathered basalts will include examination by electron microprobe and a scanning electron microscope equipped with an energy dispersive chemical analyzer. This work will answer the question of whether microbes cause the weathering of volcanic glass and whether this process substantially impacts biogeochemical cycles in the oceans. It will also determine whether volcanic glass can serve as a viable substrate to support life in the deep ocean crust. Broader impacts include the development and refinement of new surface analytical techniques, support and training of a Postdoctoral Scholar and a Ph.D. student. It will also make available data and research resources for high/middle schoolteachers and students through the Internet via databases and websites.