Collaborative Proposal: Site Survey and Initial Characterization of North Pond: Microbiology, Biogeochemistry, Seismic Profiles

合作提案：北池塘的现场调查和初步表征：微生物学、生物地球化学、地震剖面

• 批准号: 0727175
• 负责人: Andreas Teske
• 金额: --
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0727175&HistoricalAwards=false
• 关键词: Collaborative; Proposal; Site; Survey; Initial

Microbial cells occur in shallow and deep sediments throughout the world's oceans. These cells constitute a major portion of the Earth's prokaryotic biomass and their activity catalyzes the decomposition of buried organic matter. Similarly, microorganisms colonize the ocean crust, leading to the oxidative alteration of young ridge flank basalts. Despite their cosmopolitan abundance, the diversity, habitat, and dispersal pathways of these organisms are poorly defined. Little is known regarding their functional genes and the metabolic activities that allow these prokaryotes to grow and survive in the young crustal environment.North Pond is an isolated northeast-trending sediment pond on the western flank of the Mid-Atlantic Ridge (MAR) at 22deg45'N and 46deg05'W; it is surrounded and underlain by young (7 Ma), porous mid-ocean ridge basalt, and it is isolated from the sediment cover of the Atlantic abyssal basins and outer ridge flanks. This setting provides a "natural laboratory" for examining subsurface microbial community dispersal pathways, occurrence, and colonization patterns. In particular studies can differentiate bacteria and archaea from the deep-sea water column, deep subsurface sediments, and ridge flank basalt. Current deep subsurface microbiology focuses on the question "What kind of microbial life is there, and why?" while avoiding its necessary complement "How did it get there?" This study will accomplish that goal with a vision toward establishing a microbial observatory at North Pond as part of future IODP campaigns. By tracing physical and chemical "signatures" in North Pond sediments, the research will constrain fluid transport pathways and flow rates, and these will be correlated to site-specific microbial composition, key metabolic gene repertoire, and biogeochemical activity of subsurface microbial communities.This research focuses on detailed mapping of the sediment-basement interface of North Pond, by coupling heat flow, seismic information, and pore fluid chemistry data to microbial sampling of the sediments. The goals are two-fold: 1) to conduct a comprehensive site survey of North Pond that includes constraining the hydrology in preparation for our upcoming IODP cruise to North Pond, and 2) to perform a survey of near-surface microbial communities in conjunction with the biogeochemical characteristics and flow paths of their sediment environment. This site survey cruise will permit necessary refinement in shipboard and shore-based methodology and sample handling in preparation of our IODP cruise.Broader Impacts. The biogeochemical activities, composition and temporal and spatial dynamics of marine subsurface communities are an emerging central topic in marine sciences and geomicrobiology. The researchers plan to integrate the findings directly into ongoing undergraduate and graduate student education at their institutions through integration of materials in coursework, and the direct involvement of an REU student. The researchers will engage the broader public via the JOI distinguished Speaker series. Finally, this site survey is part of a much larger vision to develop North Pond into an internationally coordinated benchmark study in subsurface microbiology (i.e., a microbial observatory).

微生物细胞存在于世界海洋的浅层和深层沉积物中。这些细胞构成了地球原核生物量的主要部分，它们的活性催化埋藏有机物的分解。同样，微生物在洋壳上定居，​​导致年轻的山脊侧玄武岩发生氧化改变。尽管它们分布广泛，但这些生物体的多样性、栖息地和扩散途径尚不清楚。关于这些原核生物在年轻的地壳环境中生长和生存的功能基因和代谢活动，人们知之甚少。北池是一个孤立的东北走向的沉积池，位于大西洋中脊 (MAR) 西翼，北纬 22 度 45 分，西经 46 度 05 分；它的周围和下方是年轻的（7 Ma）、多孔的洋中脊玄武岩，并且与大西洋深海盆地和外脊侧翼的沉积物覆盖层隔离。这种环境提供了一个“天然实验室”，用于检查地下微生物群落的扩散途径、发生和定殖模式。特别是研究可以将细菌和古细菌与深海水柱、深层地下沉积物和山脊侧面玄武岩区分开来。当前深层地下微生物学关注的问题是“那里有什么样的微生物生命，为什么？”同时避免其必要的补充“它是如何到达那里的？”这项研究将实现这一目标，其愿景是在北池塘建立微生物观测站，作为未来 IODP 活动的一部分。通过追踪北池沉积物中的物理和化学“特征”，该研究将限制流体输送路径和流速，并将这些与特定地点的微生物组成、关键代谢基因库和地下微生物群落的生物地球化学活动相关联。这项研究的重点是通过耦合热流、地震信息、 以及沉积物微生物采样的孔隙流体化学数据。目标有两个：1) 对北池塘进行全面的现场调查，包括限制水文，为我们即将前往北池塘的 IODP 巡航做准备；2) 对近地表微生物群落及其沉积物环境的生物地球化学特征和流动路径进行调查。这次现场调查巡航将允许对船上和岸基方法以及样本处理进行必要的改进，以准备我们的 IODP 巡航。更广泛的影响。海洋地下群落的生物地球化学活动、组成以及时空动态是海洋科学和地球微生物学的一个新兴中心课题。研究人员计划通过将材料整合到课程作业中以及 REU 学生的直接参与，将研究结果直接整合到所在机构正在进行的本科生和研究生教育中。研究人员将通过 JOI 杰出演讲者系列吸引更广泛的公众。最后，这次现场调查是一个更大愿景的一部分，旨在将北池塘发展成为地下微生物学国际协调基准研究（即微生物观测站）。