Molecular-isotopic studies of microbial processes and organic matter in the subseafloor coalbed biosphere of Shimokita (IODP Exp. 337)

该提案寻求继续支持与IODP第337次考察（2012年7月26日至9月30日）有关的巡航后研究，Kai-Uwe Hinrichs教授（支持者）及其同事Verena Heuer博士、Yu-Shih Lin博士和马歇尔鲍尔斯博士分别作为联合首席科学家和船上科学家参加了该研究。IODP失效337是第一个利用隔水管钻井技术对海底碳氢化合物系统进行取芯和取样的科学海洋钻井计划。C 0020 A孔的水深为1180 m，沉积物总深度为2466 m。它是目前科学海洋钻探所钻的最深的洞。该探险队旨在探索与日本海底以下约2公里深埋煤层相关的微生物生态系统和微生物过程，并探测和检查科学钻探所能到达的最深微生物群落的特征。我们建议调查微生物和有机质之间的烃系统的下北半岛的多样性关系。特别是，我们打算解决以下问题：煤层作为地球生物反应器，维持微生物的生命在大埋深？煤衍生化合物的转化和迁移是否影响深层和上覆浅层的碳流和生物量？深海生物圈延伸到海底有多深，生命的限制因素是什么？我们打算使用有机地球化学方法，包括定性，定量和分子同位素分析的气体，溶解的有机物，和极性膜脂代表活的微生物生物量。我们将在基于培养的实验室实验中测试我们关于煤层作为深层生物圈的能源和碳源的假设。为了阐明代谢途径，我们将使用碳和氢的稳定同位素和碳的放射性同位素作为示踪剂。这些技术将提供洞察有机物的生物降解，原核生物量，碳代谢和微生物群落在沉积环境中的活动。

This proposal seeks continued support for post-cruise research related to IODP Expedition 337 (July 26 to September 30, 2012), in which Prof. Dr. Kai-Uwe Hinrichs (proponent) and his co-workers Drs. Verena Heuer, Yu-Shih Lin, and Marshall Bowles participated as co-chief scientist and shipboard scientists, respectively. IODP Exp. 337 was the first scientific ocean drilling initiative to core and sample a subseafloor hydrocarbon system using riser-drilling technology. Hole C0020A was drilled at a water depth of 1180 m and reached a total sediment depth of 2466 m. It is currently the deepest hole that was drilled by scientific ocean drilling. The expedition seeks to explore the microbial ecosystem and microbial processes associated with a deeply buried coalbed situated ~2 km below the seafloor off Japan as well as to detect and examine the signatures of the deepest microbial communities ever accessed by scientific drilling. We propose to investigate the diverse relationships between microorganisms and organic matter in the hydrocarbon system off the Shimokita peninsula. In particular, we intend to address the following questions: Does the coalbed act as geobiological reactor that sustains microbial life at great burial depth? Do the conversion and transport of coal-derived compounds influence carbon flow and biomass at depth and in the overlying shallower strata? How deep does the deep biosphere extend into the seafloor and what are the limiting factors for life? We intend to use organic geochemical approaches including qualitative, quantitative, and molecular-isotopic analyses of gases, dissolved organic matter, and polar membrane lipids representative of live microbial biomass. We will test our hypothesis on the role of coalbeds as energy and carbon sources for the deep biosphere in cultivation-based laboratory experiments. In order to elucidate metabolic pathways we will use stable isotopes of carbon and hydrogen and the radioisotope of carbon as tracers. These techniques will provide insights into biodegradation of organic matter, quantities of prokaryotic biomass, and carbon metabolism and activities of microbial communities in sedimentary environments.