Collaborative Research: Geochemical Effects on the Functional Microbial Community Dynamics of Hydrothermal Deposits along the Eastern Lau Spreading Center

合作研究：地球化学对刘东部扩散中心热液矿床功能微生物群落动态的影响

• 批准号: 1233037
• 负责人: Jeffrey Seewald
• 金额: $ 23.84万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1233037&HistoricalAwards=false
• 关键词: Collaborative; Research; Geochemical; Effects; Functional

Extreme environmental gradients exist at deep-sea hydrothermal vents where high temperature, low pH and reduced fluids mix with cold oxygenated seawater. This results in a plethora of microbes taking advantage of abundantly available microniches. From small subunit (16S) rRNA gene surveys and directed enrichment culturing of vent deposits from many sites, patterns in diversity are emerging that suggest that geochemical processes, particularly those that affect fluid pH, play a fundamental role in regulating microbial diversity and community composition. This a three year study at vent fields along the Eastern Lau Spreading Center (ELSC) to investigate the relationship between vent geochemistry and microbial community dynamics. The ELSC was chosen because it provides large and systematic changes in fluid and rock geochemistry, spreading rate, magmatic/tectonic processes, and proximity to the volcanic arc over its relatively short length of 397 km. The individual vent fields therefore provide excellent natural laboratories for exploring, in depth, the factors that influence the diversity and relationships of microbial communities associated with actively forming deep-sea hydrothermal deposits. The study will be carried out at 3 geochemically different hydrothermal fields along the ELSC. The scientists will document microbial community composition and diversity associated with hydrothermal deposits from each area for comparison with data obtained in 2009 and 2005. The close proximity of these geochemically distinct vent areas within the ELSC provides an ideal opportunity to investigate the effect of vent fluid and deposit geochemistry on the structure and function of microbial communities, as well as the specific roles of individual populations, associated with active hydrothermal deposits. The investigators hypothesize that, given the extreme environmental characteristics (e.g., low fluid pH and high iron at Mariner), they will see distinct differences in the metagenomes and particularly in the metatranscriptomes among the Kilo Moana, ABE and Mariner vent fields. The specific objectives are to: 1) Link geochemical and microbial dynamics along the ELSC (from 2005-­2013); 2) Use of metagenomic and transcriptomic data to explore biogeochemical cycles that are regulating the functional roles of the microbial communities in vent fields along the ELSC; and 3) Use the metagenomic information to enrich for targeted novel Thermoprotei and acidophiles. Active hydrothermal metal sulfide deposits and fluid samples will be collected from the vent fields along the ELSC. Bar-coded pyrosequencing of archaeal and bacterial 16S rRNA amplicons will be obtained for over eighty samples. The geochemical environment of the chimneys will be modeled to determine in situ geochemical conditions. These values will be used in statistical analyses to explore the factors affecting the observed differences in the communities. Using the 16S rRNA gene 454 pyrotags coupled with the geochemical characterization, specific samples will be selected for metagenomic and metatranscriptomic analyses (1-3 of each per site). The molecular information will be used to target specific samples that: (i) harbor novel unclassified diversity; (ii) have vent endemic lineages; and (iii) have acidophilic relatives from terrestrial systems, for enrichment culturing (using the geochemistry to help constrain culturing conditions). Broader Impacts. The project will expand our understanding of the extent of the microbial biosphere. At least one graduate student will participate in interdisciplinary studies that involve next-­generation sequencing, molecular microbial ecological techniques, and geochemical modeling. ALR will involve a registered PSU Pacific Islander student in the research and requested research cruise. Undergraduate students from Bridgewater State University will be involved in the fluid sampling program, thereby providing a meaningful and exciting research experiences. The PIs will share the excitement of new deep-sea vent discoveries with the public through writing general articles, giving lectures at schools, and through continuing education for school teachers through existing programs (e.g. through the Saturday Academy, PSU (http://www.saturdayacademy.org/).

极端环境梯度存在于深海水热通风孔，高温，低pH和速度降低的烟道与冷氧气的海水混合在一起。这导致了许多微生物利用了绝对可用的微观。从小型亚基（16s）rRNA基因调查和许多位置的通风矿床的富集培养物，多样性的模式正在出现，表明地球化学过程，尤其是那些影响流体pH的过程，在调节微生物多样性和社区组成方面起着基本作用。这项在东部刘扩散中心（ELSC）的通风田进行了为期三年的研究，以研究排气地球化学与微生物社区动态之间的关系。之所以选择ELSC，是因为它提供了流体和岩石地球化学，扩散速率，岩浆/构造过程以及与火山弧相对短的397 km的相对短长度的巨大变化。因此，单个排气场为探索与积极形成深海氢基沉积物相关的微生物群落的多样性和关系的因素提供了出色的天然实验室。该研究将在沿ELSC的3个地球化学不同的热液场进行。科学家将记录与每个区域的水热沉积相关的微生物群落组成和多样性，以与2009年和2005年获得的数据进行比较。ELSC中这些地球化学上不同的通风口区域的紧密近端提供了研究通风流体的理想机会，可以研究通风流体的效果，并将地球化学对微生物社区的结构和功能的效果以及各个人群相关。研究人员假设，鉴于极端的环境特征（例如，水手在水手中的低流体pH和高铁），他们将看到宏基因组，尤其是在基洛·莫阿纳（Kilo Moana），安倍晋三和水手通风口领域的元文字中的明显差异。特定目标是：1）沿ELSC链接地球化学和微生物动力学（从2005年至2013年）； 2）使用元基因组和转录组数据探索正在调节微生物群落在ELSC沿通风口领域中的功能作用的生物地球化学周期； 3）使用宏基因组信息丰富针对靶向的新型热蛋白和嗜酸剂。沿ELSC的排气场将收集活性的热液金属硫化物沉积物和流体样品。将对超过80个样品获得档案和细菌16S rRNA扩增子的钢筋编码的焦磷酸测序。将对烟囱的地球化学环境进行建模，以确定原位地球化学条件。这些值将用于统计分析中，以探索影响社区观察到的差异的因素。使用16S rRNA基因454烟火结合地球化学表征，将选择特定的样品进行元基因组和元文字分析（每个位点的1-3）。分子信息将用于针对特定样本：（i）具有新颖的未分类多样性； （ii）有通风内族谱系； （iii）具有来自陆生系统的嗜酸亲戚，用于富集培养物（使用地球化学来帮助约束文化条件）。更广泛的影响。该项目将扩大我们对微生物生物圈程度的理解。至少一名研究生将参加涉及下一代测序，分子微生物生态技术和地球化学建模的跨学科研究。 ALR将涉及一名注册的PSU Pacific Islander学生参与研究，并要求进行研究。布里奇沃特州立大学的本科生将参与流体抽样计划，从而提供有意义且令人兴奋的研究经验。 PI将通过撰写一般文章，向学校讲座以及通过现有课程为学校教师进行继续教育（例如，通过星期六学院，PSU（http://www.saturdayacademy.org/），通过撰写一般文章，在学校讲座和继续教育，与公众分享新的深海发泄发现的兴奋。