LEXEN: Collaborative Research: A Window into the Extreme Environment of Deep Subsurface Microbial Communities: Witwatersrand Deep Microbiology Project

LEXEN：合作研究：了解深层地下微生物群落极端环境的窗口：Witwatersrand 深层微生物学项目

• 批准号: 9714214
• 负责人: Tullis Onstott
• 金额: $ 19.25万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-10-01 至 1999-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9714214&HistoricalAwards=false
• 关键词: LEXEN; Collaborative; Research; Window; into

9714214 Onstott Recent investigations have identified microbial communities in various crustal environments down to 2800 meters below the surface (mbls). Only a hand full of deep microbial samples from continental crust (500 mbls.) exists, however, because coring is expensive. The gold mines of the 2.9 Ga Witwatersrand Supergroup in South Africa, however, provide a unique opportunity to study microbial communities at depths ranging from 2000 to 3500 mbls. And eventually up to 5000 mbls. Reconnaissance samples of a uranium-rich, gold-bearing, carbonaceous rock and of water from a gallery borehole were collected for microbial analyses from mined depth of 3200 mbls., where the rock and water temperatures were 50 to 55(C. Measures were taken to avoid contamination during mining and sampling. Samples were shipped to the U.S.A. in sterile, anaerobic canisters on ice, processed under sterile anaerobic conditions and distributed to other microbiology labs. Microscopic observations indicated the presence of intact cells in both types of samples. Electron microscopy reveals filamentous microorganisms in the rock samples. Phospholipid fatty acid and DNA analyses indicate that the rock samples contain Cyanobacteria and sulfate-reducing bacteria (SRB). Growth was detected in aerobic and anaerobic enrichments of the rock samples. The water sample yielded a strain of Thermus that is the first reported Thermus to reduce Fe (III) and the first facultative, thermophilic Fe (III) reducing bacteria (IRB). Funds are requested to return to South Africa, set up a sample-processing laboratory on site, and carry out a three-month field study to address the following issues raised by this sample reconnaissance: ( To what extent are rock and water samples contaminated by mining activity and what sampling strategies must be developed to reduce and quantify this contamination? Specifically, do the Cyanobacteria represent mining contamination? ( Does the radiation emanating from the uranium-rich, car bonaceous layer provide a significant source of energy for indigenous microbial communities? In particular, does the radiolytic reaction with water generate sufficient oxygen for the growth of facultative microorganisms like IRB-SA? ( If these microbial communities have been present in the rock since the time of the last thermal episode at 2.0 Ga, then does the in situ activity of the SRB and IRB explain the occurrence of framboidal pyrite and filamentous aggregates of gold? To address the first question, samples of mining water, borehole water, and filtered air samples will be collected and analyzed. For the second question, rock samples of the carbonaceous layer and host rock will be collected with aseptic methods in a three dimensional grid (3x3x12 meter) during excavation of an access tunnel. To answer the second and third question, the relationships between the mineralogy and the bacteria in the rocks will be examined in situ and the capability of the cultured microorganisms to precipitate minerals at in situ conditions will be examined. To constrain the habitation time of the microbial community, the present day and paleo hydrology will be modeled using thermal constraints provided by borehole temperatures and thermochronometry. Incubations of all samples will be initiated on site. Off site analyses during the subsequent 21 months will include 1) phospholipid, glycolipid, ether lipid analyses (Univ. of Tenn.); 2) DNA extraction, polymerase chain reaction (PCR) amplification, cloning, and sequencing (Pacific Northwest National Laboratories-PNNL); 3) acridine orange direct counts (AODC), in situ probe, and field emission gun scanning electron microscopy (FEG-SEM) (Princeton-Rutgers); 4) chemical and isotopic analyses (Princeton-Indiana University); 5) fission track apatite analyses (Princeton-Univ. of Penn.). 6) Phosphorimaging of SRB and uranium reducing activity (PNNL-Princeton).

9714214 ONSTOTT最近的调查已经确定了各种地壳环境中的微生物群落，低于地面以下2800米（MBL）。 但是，只有一只装满了来自大陆壳（500 mbl）的深层微生物样品。但是，由于加油很昂贵。 然而，南非2.9 GA Witwatersrand超级群的金矿为研究微生物群落的深度提供了独特的机会，范围为2000至3500 mbl。最终可达5000 mbl。 收集富含铀，含金，碳岩和水的侦察样品，以从3200 mbl的开采深度进行微生物分析，以进行微生物分析，岩石和水温为50至55（c。采取措施。无菌的厌氧条件和其他微生物学的观测表明，在两个类型的电子显微镜中都存在完整的细胞。岩石样品的厌氧富集产生了一系列热量，这是第一个减少Fe（III）和第一个辅助的嗜热FE（III）还原细菌（IRB）的热量。 要求资金返回南非，在现场建立样本处理实验室，并进行为期三个月的现场研究，以解决该样品侦察所提出的以下问题：（在多大程度上，岩石和水样在多大程度上受到采矿活动的污染，必须开发出什么样本策略，以减少和量化这种污染物？富含铀的汽车构成层为土著微生物群落提供了重要的能量来源吗？将收集和分析黄铁矿和黄金的丝状骨料？ 在第二个问题上，在开挖通道隧道期间，将使用三维网格（3x3x12米）的无菌方法收集碳质层和宿主岩石的岩石样品。 为了回答第二和第三个问题，将在原位检查矿物学与岩石中细菌之间的关系，并将检查培养的微生物在原位条件下沉淀矿物质的能力。 为了限制微生物群落的居住时间，将使用井眼温度和热量学计提供的热约束对当今和古水文学进行建模。 所有样品的孵育将在现场启动。 在随后的21个月内进行现场分析，将包括1）磷脂，糖脂，醚脂质分析（Tenn。）； 2）DNA提取，聚合酶链反应（PCR）扩增，克隆和测序（Pacific Northwest National Laboratories-PNNL）； 3）Acridine Orange Direct Counts（AODC），原位探针和现场发射枪扫描电子显微镜（FEG-SEM）（Princeton-Rutgers）； 4）化学和同位素分析（普林斯顿 - 印度大学）； 5）裂变轨道磷灰石分析（Penn。 6）SRB和铀还原活性（PNNL-PRINCON）的磷光成像。