Collaborative Research: Microbial Ecology of Ocean Basement Aquifers: ODP Borehole Observatories

洋壳由在大洋中脊(MOR)形成的基岩加上随着基岩老化并远离大洋中脊而积累的上覆沉积物组成。越来越多的证据表明，在莫尔盆地两侧和海洋盆地的全球系统之下，存在着大量老化的、被沉积物掩埋的基底，存在着大量的生物圈。目前的项目将利用长期海洋钻探计划钻孔观测站(软木塞)提供的前所未有的机会，收集未受污染的基底流体样本，以进行地球化学、微生物学和生态表征。由于水-岩反应和相关的微生物生境随着基底温度和年龄的不同而不同，因此将研究Juan de Fuca Ridge(JFR)两侧多个钻孔观测站的基底流体的地球化学和分子(遗传)多样性，范围从基底年龄(约1.24至350万年)和基底温度(38至65摄氏度)不等。水-岩石和水(例如，氧化-还原)反应和生活在它们附近的生物体之间的协同作用要求采用跨学科的方法进行研究。在这个项目中，微生物群落和代谢多样性将与地球化学过程密切结合起来进行研究。在现场，实时分析将同时测量关键的溶解还原-氧化(氧化还原)物种；这种测量将有助于阐明基底流体的代谢气候(例如，微生物如何获得能量和固定碳)，并指导本研究的培养部分。这些地球化学和生物学研究将为许多潜在代谢反应的热力学计算提供输入数据(例如，一种能量‘路线图’)，这将为某些代谢的发生提供‘现实检验’。地球化学测量和能量计算将为微生物群落协同作用的现实建模提供亟需的环境背景。参与机构的首席调查人员和学生将与许多其他机构的水文地质学家、地球化学家和技术员以及国际大洋钻探计划(IDOP)的工作人员密切互动，以利用现有的科克观测站，并影响对海洋基底微生物群落研究最有利的新钻孔观测站的发展。多名本科生、研究生和博士后将密切参与该项目的所有阶段，并将受益于跨机构的非正规教育和培训。该项目将与密歇根大学的NASA天体生物学研究所(NAI)积极互动，对该研究所而言，海底生物圈研究是一个日益重要的组成部分。学生和个人将参加面向K-12学校和普通公众的教育推广项目，特别是继续非常成功的船到教室和“海上教师”推广计划；后者将把K-12科学教师直接纳入项目的各个方面，从最初的规划到实地和实验室工作。

The ocean crust consists of basement rock formed at the mid-ocean ridges (MOR) plus the overlying sediments that accumulate over time as the basement rock ages and moves away from the MORs. There is growing evidence that a substantial biosphere exists throughout the immense volume of aging, sediment-buried basement underlying the global system of MOR flanks and ocean basins. The current project will exploit the unprecedented opportunities provided by long-term Ocean Drilling Program borehole observatories (CORKs) to collect uncontaminated samples of basement fluids for geochemical, microbiological and ecological characterization. Because water-rock reactions and associated microbial habitats vary with basement temperature and age, the geochemistry and molecular (genetic) diversity will be examined in basement fluids from multiple borehole observatories on the flanks of the Juan de Fuca Ridge (JFR), ranging in basement age (ca.1.24 to 3.5 million years) and in basement temperature (38 to 65degrees centigrade). The synergy between water-rock and aqueous (e.g., oxidation-reduction) reactions and the organisms living in proximity to them demands an interdisciplinary approach to research. In this project, the microbial community and metabolic diversity will be studied in close conjunction with geochemical processes. In situ, real-time analyses will simultaneously measure key dissolved reduction-oxidation (redox) species; such measurements will help to elucidate the metabolic climate of the basement fluids (e.g., how the microbes gain energy and fix carbon) and guide culturing portions of this study. These geochemical and biological studies will provide input data for thermodynamic calculations of numerous potential metabolic reactions (e.g., a sort of energy 'road map'), which will provide a 'reality-check' for the occurrence of certain metabolisms. Geochemical measurements and energetic calculations will provide a much-needed environmental context for realistic modeling of microbial community synergy. The principal investigators and students from the participating institutions will interact closely with hydrogeologists, geochemists and technologists from numerous other institutions, as well as with staff of the International Ocean Drilling Program (IDOP) to both exploit existing CORK observatories and to influence development of new borehole observatories that are optimal for ocean basement microbial community studies. Multiple undergraduate, graduate and post-doctoral students will be intimately involved in all stages of the project, and will benefit from cross-institutional informal education and training. The project will actively interact with UH's NASA Astrobiology Institute (NAI), for which subseafloor biosphere studies is an increasingly significant component. Students and PIs will participate in educational outreach projects to K-12 schools and the general public, especially including continuation of the very successful ship-to-classroom and "Teacher at Sea" outreach programs; the latter will involve integrating K-12 science teachers directly into all aspects of the project from initial planning to field and laboratory work.