Collaborative Research: Delineating The Microbial Diversity and Cross-domain Interactions in The Uncharted Subseafloor Lower Crust Using Meta-omics and Culturing Approaches

下洋壳大部分尚未勘探，是地球上生物勘探的最后前沿之一。初步数据表明，从西南印度洋亚特兰蒂斯岸海底以下790米深处采集的下大洋地壳样品中存在活跃的地下生物圈。即使生命只存在于温度允许且流体流动可以提供碳和能源的可居住体积的一小部分中，活跃的下海洋地壳生物圈也会对深层碳预算产生影响，并产生对早期地球上可能存在的微生物群的见解。这对其他研究学科、教育工作者和学生都很感兴趣。K-12教育计划将利用推广合作者A.马丁内斯，一个七年级的教师在鹰通行证，得克萨斯州，谁航行作为外展专家钻井远征360。马丁内斯在一所1级学校工作，那里有98%的西班牙裔学生和2%的美洲原住民学生，以及大量的英语学习者和移民。每年进行一次学校访问，在此期间，项目研究人员将向学生介绍微生物学的实践活动，并就海洋微生物学，项目以及如何追求科学相关职业进行会谈。此外，每月与学生和PI举行Skype会议，更新项目进展情况。学生每年前往得克萨斯大学海洋科学研究所，在那里他们可以参观校园，并在R/V凯蒂上进行3小时的巡航，在此期间，他们学习并帮助不同的海洋学采样方法。该项目部分支持两名研究生，一名伍兹霍尔本科暑期学生，多名德克萨斯A+M本科生的参与，以及两个机构的3名主要研究人员，其中包括一名早期职业研究人员，他以前没有接受过NSF的支持。由于缺乏对下大洋地壳的了解，该项目有望改变我们对这一广阔环境中生命的理解。该项目评估了这一地壳生物圈中所有三个生命领域的代谢功能，重点是营养循环和评价与其他深海微生物生境的联系。下洋壳是一个潜在的巨大生物圈，其微生物成分及其介导的地球化学循环可能通过断层和地下流体流动与深海过程有关。亚特兰蒂斯浅滩是一个构造窗口，直接暴露了海底的下大洋地壳。这使得海底钻探和环境研究能够改变我们对深海海底生物圈与海洋其他部分之间联系的理解。对从360号探险队回收的岩石的初步分析表明，海水与下大洋地壳的相互作用创造了各种地球化学条件，能够通过提供营养和化学能量来支持各种微生物生命。 该项目是对地下室样品中所有3个生命领域的微生物学的第一次跨学科调查，结合了多样性和“元组学”分析，营养添加实验分析，高通量培养和分离物生理分析，包括评估其利用特定碳源的能力，拉曼光谱和脂质生物标志物分析。比较基因组学被用来将这些样本中与碳循环有关的基因和途径与已发表的其他深海环境研究的数据进行比较。收集的样本提供了一个难得的和时间敏感的机会，以获得详细的了解微生物生命，这种生命的可用碳和能源，以及微生物群的分散和下大洋地壳与上覆无光水柱之间的地球化学过程的联系。

The lower ocean crust has remained largely unexplored and represents one of the last frontiers for biological exploration on Earth. Preliminary data indicate an active subsurface biosphere in samples of the lower oceanic crust collected from Atlantis Bank in the SW Indian Ocean as deep as 790 m below the seafloor. Even if life exists in only a fraction of the habitable volume where temperatures permit and fluid flow can deliver carbon and energy sources, an active lower oceanic crust biosphere would have implications for deep carbon budgets and yield insights into microbiota that may have existed on early Earth. This is all of great interest to other research disciplines, educators, and students alike. A K-12 education program will capitalize on groundwork laid by outreach collaborator, A. Martinez, a 7th grade teacher in Eagle Pass, TX, who sailed as outreach expert on Drilling Expedition 360. Martinez works at a Title 1 school with ~98% Hispanic and ~2% Native American students and a high number of English Language Learners and migrants. Annual school visits occur during which the project investigators present hands on-activities introducing students to microbiology, and talks on marine microbiology, the project, and how to pursue science related careers. In addition, monthly Skype meetings with students and PIs update them on project progress. Students travel to the University of Texas Marine Science Institute annually, where they get a campus tour and a 3-hour cruise on the R/V Katy, during which they learn about and help with different oceanographic sampling approaches. The project partially supports two graduate students, a Woods Hole undergraduate summer student, the participation of multiple Texas A+M undergraduate students, and 3 principal investigators at two institutions, including one early career researcher who has not previously received NSF support of his own. Given the dearth of knowledge of the lower oceanic crust, this project is poised to transform our understanding of life in this vast environment. The project assesses metabolic functions within all three domains of life in this crustal biosphere, with a focus on nutrient cycling and evaluation of connections to other deep marine microbial habitats. The lower ocean crust represents a potentially vast biosphere whose microbial constituents and the biogeochemical cycles they mediate are likely linked to deep ocean processes through faulting and subsurface fluid flow. Atlantis Bank represents a tectonic window that exposes lower oceanic crust directly at the seafloor. This enables seafloor drilling and research on an environment that can transform our understanding of connections between the deep subseafloor biosphere and the rest of the ocean. Preliminary analysis of recovered rocks from Expedition 360 suggests the interaction of seawater with the lower oceanic crust creates varied geochemical conditions capable of supporting diverse microbial life by providing nutrients and chemical energy. This project is the first interdisciplinary investigation of the microbiology of all 3 domains of life in basement samples that combines diversity and "meta-omics" analyses, analysis of nutrient addition experiments, high-throughput culturing and physiological analyses of isolates, including evaluation of their ability to utilize specific carbon sources, Raman spectroscopy, and lipid biomarker analyses. Comparative genomics are used to compare genes and pathways relevant to carbon cycling in these samples to data from published studies of other deep-sea environments. The collected samples present a rare and time-sensitive opportunity to gain detailed insights into microbial life, available carbon and energy sources for this life, and of dispersal of microbiota and connections in biogeochemical processes between the lower oceanic crust and the overlying aphotic water column.