Collaborative Research: ETBC: Deep Crustal Biosphere: Microbial Cycling of Carbon

智力上的功绩。在过去二十年里，来自世界各地的研究揭示了地下微生物生态系统的范围和种类，其中包括大陆和海洋环境中的各种地质环境。从极地永久冻土和冰盖到赤道海洋沉积物，从透水含水层到4公里深的裂隙岩石，从深层包气带到油藏，发现了包括许多新物种在内的各种细菌和古菌组合。随着陆壳和洋壳深度和温度的增加，地表气候变化和光球层过程对次表层微生物生态系统的影响减弱，而用有机和无机营养物质丰富结壳的类Fisher-Tropsch过程和辐射分解过程变得越来越重要。无论有机碳的来源如何，控制其生物降解为二氧化碳和甲烷的规则应该与石油储藏库的规则相似。该项目的目标是确定这些规则，确定地下微生物生态系统对有机物的生物降解的速率和限度，并确定谁对此负责。为实现这些目标，调查人员将利用南非威特沃特斯兰德盆地矿山中随处可见的钻孔(深度从0.8至3.8公里不等)，研究浅层有机光合作用和深层非生物成因碳氢化合物的生物降解所涉及的程度和物种间相互作用。通过结合使用1)气相色谱、高效液相和核磁共振表征DOC，2)DOC、DIC、碳氢化合物、脂肪和有机酸的13C分析，3)碳氢化合物的H同位素分析，4)CH4、DIC、DOC和脂肪的14C分析，以及5)16S rRNA的稳定同位素探针(SIP)，我们将描绘1)化学自养产生的有机酸，2)非生物产生的碳氢化合物，3)热生产生的有机酸和4)从表面光圈产生的溶解有机物(DOC)在碳代谢过程中对次表层微生物群落结构及其营养相互作用的相对重要性。这些分析将对从数千年到数千万年的裂隙水中收集的浮游微生物群落进行。更广泛的影响。该研究项目将让本科生和毕业生参与实践跨学科研究，他们将把同位素地球化学和有机地球化学分析与遗传分析结合起来。来自北美和南非的学生将参与实地和实验室研究，这是与南非科学家正在进行的合作的一部分。RNA-SIP孵化实验将伴随着分离实验，这将进一步扩大该大学的地下培养收集和遗传数据库。(F)加强其生物修复和生物技术方面的努力。该项目将开始整合与碳代谢有关的遗传、分类和功能多样性。研究人员将致力于将一个基于网络的地下微生物数据库与一个可供下载用于新闻发布的地下微生物的扫描电子显微镜/透射电子显微镜图像图库结合在一起；作为图库的一部分，我们将发起一个“这种微生物在世界上哪里发生？”描述在哪里发现了相关的菌株或序列。该网站将提供一个关于地下深层微生物生物地理数据库的开端。在采矿公司允许的情况下，抽样考察的视频将在网站上公布。该项目还将为优化开发威特沃特斯兰德盆地未开发的天然气藏以及私营公司在南非开发二氧化碳封存项目提供基本的科学基础

Intellectual Merit. For the past two decades studies from around the world in a wide variety of geological environments in both continental and marine settings have revealed the extent and variety of subsurface microbial ecosystems. From polar permafrost and ice sheets to equatorial marine sediments, from permeable aquifers ~200 meters deep to fractured rock 4 km deep, from deep vadose zones to oil reservoirs, diverse assemblages of bacteria and archaea, including many novel species, have been discovered. As depth and temperature increase in both the continental and oceanic crust, the effects of changing surface climate and photospheric processes on the subsurface microbial ecosystem diminish while Fisher-Tropsch-like and radiolytic processes, which enrich the crust with a mixture of organic and inorganic nutrients, become increasingly important. Regardless of the origin of the organic carbon, the rules that govern its biodegradation to CO2 and CH4 should be similar to those for petroleum reservoirs. The goals of this project are to determine those rules, determine the rates and limits of the biodegradation of organic matter by subsurface microbial ecosystems, and determine who is responsible. To accomplish these goals, investigators will utilize the readily accessible boreholes present in the mines of the Witwatersrand Basin, South Africa, which range in depth from 0.8 to 3.8 km, to examine the extent of and the inter-species interactions involved in biodegradation of organic photosynthate in shallow depths and abiogenic hydrocarbons at great depth. By employing a combination of 1) GCMS, HPLC, and NMR characterization of the DOC, 2) 13C analyses of DOC, DIC, hydrocarbons, lipids, and organic acids, 3) H isotope analyses of hydrocarbons, 4) 14C analyses of CH4, DIC, DOC, and lipids, and 5) stable isotope probes (SIP) of the 16S rRNA, we will delineate the relative importance of 1) chemoautotrophically produced organic acids, 2) abiogenically produced hydrocarbons, 3) thermogenically produced organic acids and 4) dissolved organic matter (DOC) from the surface photosphere, to the subsurface microbial community structure and its trophic interactions during carbon metabolism. These analyses will be performed on planktonic microbial communities collected from fracture water ranging in age from thousands of years to tens of millions of years. Broader Impacts. The program of study will engage undergraduates and graduates in hands-on interdisciplinary research where they will integrate isotope geochemistry and organic geochemical analyses with genetic analyses. Students from North America and South Africa will participate in the field and laboratory research as part of an ongoing collaboration with South African scientists. The RNA-SIP incubation experiments will be accompanied by isolation experiments that will further enlarge the subsurface culture collection and genetic database at the Univ. of Free State (UFS) and enhance their bioremediation and biotechnology efforts. The project will begin to integrate the genetic, taxonomic and functional diversity with respect to carbon metabolism. Investigators will work to assemble a web-based subsurface microbial database with a gallery of SEM/TEM images of subsurface microorganisms that can be downloaded for press releases; and as part of the gallery we will initiate a "Where in the world does this organism occur?" describing where related strains or sequences have been found. The web site will provide the beginnings of a microbial biogeographical database for the deep subsurface. When permitted by the mining companies videos of the sampling expeditions will be posted on the web site. The project will also provide fundamental scientific underpinnings for optimal exploitation of untapped natural gas reservoirs in the Witwatersrand Basin and for the development of CO2 sequestration projects in South Africa by private firms