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

这项建议寻求继续支持与IODP Expeation 337(2012年7月26日至9月30日)相关的邮轮后研究，在这项研究中，Kai-Uwe Hinrichs教授(倡议者)及其同事Verena Heuer博士、林宇诗博士和马歇尔·鲍尔斯博士分别作为联席首席科学家和船上科学家参与。IODP Exp337是利用立管钻井技术对海底碳氢化合物系统进行取心和取样的第一项科学海洋钻探举措。C0020A孔的水深为1180米，总沉积深度为2466米，是目前科学钻探的最深孔。探险队试图探索与位于日本近海海底约2公里处的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到达的最深微生物群落的特征。我们建议研究岛下半岛外油气系统中微生物和有机质之间的不同关系。特别是，我们打算解决以下问题：煤层是否作为地质生物反应堆，在巨大的埋藏深度维持微生物生命？煤基化合物的转化和运输是否影响深层和上覆浅层的碳流和生物量？深层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，包括对代表活微生物生物量的气体、溶解有机物和极性膜脂进行定性、定量和分子同位素分析。我们将在以栽培为基础的实验室实验中检验我们关于煤层作为深层生物圈的能源和碳源的作用的假设。为了阐明代谢途径，我们将使用碳和氢的稳定同位素以及碳的放射性同位素作为示踪剂。这些技术将提供对沉积环境中有机物的生物降解、原核生物生物量以及碳代谢和微生物群落活动的深入了解。

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.