LExEn: Role of Atmospheric Trace Gases in Microbial Colonization and Succession on Recent Lava Flows

LExEn：大气痕量气体在微生物定殖和近期熔岩流演替中的作用

• 批准号: 0085495
• 负责人: Gary King
• 金额: $ 47.5万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-10-15 至 2004-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0085495&HistoricalAwards=false
• 关键词: LExEn; Role; Atmospheric; Trace; Gases

DEB-0085495Gary M. KingDrs. Gary M. King of the University of Maine and Klaus Nusslein of the University of Massachusetts-Amherst have been awarded a grant from the NSF Life in Extreme Environment (LExEn) program to determine the role of atmospheric trace gases in microbial colonization and succession on recent lava flows. Volcanic activity has played an important role in the development of terrestrial ecosystems for much of Earth's history, and continues to shape terrestrial environments at present. Deposition of lava and tephra result in surfaces that over time support complex, highly productive biological communities. However, young or recently extruded lavas represent extreme environments that contain few of the major nutrients necessary for sustaining life. Neither organic matter nor a fixed form of nitrogen (e.g., ammonium or nitrate) are readily available within or on the matrix of young lava. Thus, early colonization of lava by microbes requires a source of exogenous nutrients. Recent observations of young Hawaiian lava indicate that the atmosphere provides a significant source of carbon and energy for early microbial colonization. In particular, trace gases such as hydrogen and carbon monoxide (and possibly methane) serve as substrates that fuel the metabolism of functionally diverse microbes. Among these microbes are bacteria that use atmospheric nitrogen as a source of cellular nitrogen, and species that form important symbioses with plants. The nature of trace gas utilization by microbes colonizing young lavas will be the primary focus of this LExEn research effort. A variety of field and laboratory studies in the vicinity of the Kilauea volcano will document relationships among lava age (emphasizing chronosequences from 0-300 yr), microbial biomass, trace gas utilization (hydrogen, carbon monoxide and methane) and precipitation regimes (e.g., moist versus dry). Extractions of genomic DNA from lava will be used to determine the diversity of microbial communities across age and climate gradients, and the diversity of specific functional groups within these communities. Finally, the research will include efforts to enrich, isolate and characterize novel trace-gas utilizing microbes from young lava and to determine the significance of such isolates in situ. The research is expected to yield new insights about the survival and dynamics of microbes in extreme environments relevant for understanding both contemporary and ancient terrestrial systems as well as systems that might exist on other planets.

DEB-0085495Gary M.国王博士加里M.缅因州大学的King和马萨诸塞大学阿默斯特分校的Klaus Nusslein获得了NSF极端环境中的生命（LExEn）计划的资助，以确定大气痕量气体在微生物定植和最近熔岩流的演替中的作用。 火山活动在地球历史的大部分时间里对陆地生态系统的发展起着重要作用，并继续塑造着目前的陆地环境。 熔岩和火山灰的沉积形成了表面，随着时间的推移，这些表面支持着复杂的、高产的生物群落。 然而，年轻的或最近挤出的熔岩代表了极端的环境，几乎不含维持生命所需的主要营养物质。 既不是有机物，也不是氮的固定形式（例如，铵或硝酸盐）容易在年轻熔岩的基质内或基质上获得。 因此，早期熔岩的微生物定居需要外源营养源。 最近对年轻的夏威夷熔岩的观察表明，大气为早期微生物的定居提供了重要的碳和能量来源。 特别是，痕量气体，如氢气和一氧化碳（可能还有甲烷），作为底物，为功能多样的微生物的代谢提供燃料。 在这些微生物中，有利用大气氮作为细胞氮来源的细菌，也有与植物形成重要共生关系的物种。 微生物对年轻熔岩的微量气体利用的性质将是LExEn研究工作的主要重点。 在基拉韦厄火山附近进行的各种实地和实验室研究将记录熔岩年龄（强调0-300年的年代序列）、微生物生物量、痕量气体利用（氢气、一氧化碳和甲烷）和降水状况（例如，潮湿与干燥）。 从熔岩中提取的基因组DNA将用于确定不同年龄和气候梯度的微生物群落的多样性，以及这些群落中特定功能群的多样性。最后，这项研究将包括利用年轻熔岩中的微生物来富集、分离和表征新的痕量气体，并确定这些分离物的原位意义。 这项研究有望产生关于极端环境中微生物生存和动力学的新见解，有助于理解当代和古代地球系统以及可能存在于其他行星上的系统。