C-RUI: Geomicrobial Processes in an Ancient Methane Seep Deposit: Resolving Temporal and Spatial Shifts in Localized Microbial Ecosystems

摘要：美国科罗拉多州坎帕尼亚区~76 Ma的Tepee Buttes提供了一个极好的机会来模拟化石甲烷渗漏中保存下来的地质微生物过程的记录，这是一个尚未实现的规模。广阔的空中范围、可达性和保存质量使得碳酸盐降水的遗传模型随着时间的推移在个别渗漏和整个领域得以发展。由于降水是由甲烷厌氧氧化（AOM）和细菌硫酸盐还原（BSR）介导的，因此地质记录可以作为局部微生物生态系统在单个渗漏的生命周期中如何在时间和空间上变化的代表。该方案旨在解决碳酸盐产生的沉积物深度，量化局部微生物生态系统产生的碳酸盐在地球化学和岩石学上是否与与化学共生无脊椎动物相关的碳酸盐不同，并模拟生物地球化学参数在时间和空间上的变化。对Tepee Buttes的初步研究表明，岩石组构的复杂共生序列，以及稳定的同位素比率，将有助于建立碳酸盐丘的形成模型，包括形成深度。细菌体化石和微生物岩的识别将使我们能够绘制出每个山丘生命周期中局部微生物生态系统的调整图。碳和氧稳定同位素分析表明，孤峰之间的序列存在差异，我们将解决这些现象。pi建议通过两个本科院校（Gustavus Adolphus和Oberlin学院）和一个主要研究型大学（密苏里大学哥伦比亚分校）的合作项目，解决微生物诱导的碳酸盐/硫化物生产的时空测序问题。这项研究需要在大约3平方公里的面积上进行详细的实地测绘、地貌学和岩石学研究以及同位素地球化学。在野外，将绘制土丘的表面成分图，以显示与碳酸盐相和无脊椎动物种群有关的微生物生态系统分布。在实验室中，我们将在早期成功的基础上，应用多方向分析方法，包括岩石学（阴极发光、x射线荧光）、SEM/EDS和稳定同位素比率（C、O和S）。知识价值。对帐篷丘成因的了解将为定义现代和古代渗流环境中微生物与沉积物的相互作用提供重要工具。古生物学家、地质学家和地球物理学家的活跃研究领域。通过采用合作的方式，pi将从微生物古生物学、埋藏学和同位素地球化学方面的各自优势中获益，重点是改进生物地球化学代理，以识别微生物生态系统的化石记录。更广泛的影响。该项目的结果将对研究化石和现代甲烷渗漏的生物地球化学模式的研究人员有价值。传播计划要求为教育工作者制作DVD/CD-ROM，向广大读者介绍甲烷渗漏中微生物-沉积物相互作用的动态和复杂世界。这项研究将为至少四名本科生提供关键的初级研究经验，他们将参与研究的各个方面，包括制定现场策略，实验室分析和准备手稿。学生将透过亲身体验及教学工作坊，认识到合作的重要性，而该计划亦将广泛影响各学院的本科生研究能力及教学方法。

AbstractThe Tepee Buttes (~76 Ma, Campanian) of Colorado provide an excellent opportunity to model the preserved record of geomicrobial processes at a fossil methane seep at a scale that has not been realized. The broad aerial extent, accessibility, and quality of preservation allow for the development of a genetic model of carbonate precipitation over time at individual seeps and throughout the entire field. As the precipitation is mediated by both anaeorobic oxidation of methane (AOM) and bacterial sulfate reduction (BSR), the geologic record serves as a proxy for how the localized microbial ecosystems vary temporally and spatially through the life cycle of an individual seep. This proposal seeks to address the depth within the sediment at which carbonate production occurs, to quantify whether the carbonate produced from localized microbial ecosystems differs geochemically and petrographically from carbonate associated with chemosymbiotic invertebrates, and to model how the biogeochemical parameters vary in time and space. Preliminary work on the Tepee Buttes has demonstrated that the complex paragenetic sequence of petrofabrics will, along with the stable isotopic ratios, be useful in developing a model of the formation of the carbonate mounds, including depth of formation. The recognition of bacterial body fossils and microbialite will allow us to map the adjustment of localized microbial ecosystems over the lifecycle of each butte. Carbon and oxygen stable isotope analyses have shown that there is variation among sequences between buttes and we will address these phenomena. The PIs propose to address the temporal and spatial sequencing of the microbially induced carbonate/sulfide production through a collaborative project involving two undergraduate institutions (Gustavus Adolphus and Oberlin Colleges) and a major research university (University of Missouri, Columbia). The research entails detailed field mapping over an approximately 3 km2 area, taphonomic and petrographic study, and isotope geochemistry. In the field, surface components of the mounds will be mapped to demonstrate microbial ecosystem distribution in relation to carbonate phases and invertebrate populations. In the laboratory, we will build upon earlier successes by applying a multi-directed analytical approach involving petrography (cathodoluminescence, x-ray fluorescence), SEM/EDS, and stable isotope ratios (C, O, and S). Intellectual Merit. Knowledge of the genesis of the Tepee Buttes will provide important tools for defining microbial-sediment interactions in modern and ancient seep settings.an active research area for (paleo) biologists, geologists, and geophysicists. By applying a collaborative approach, the PIs will gain from the individual strengths in microbial paleontology, taphonomy, and isotope geochemistry focused on refining biogeochemical proxies for recognizing the fossil record of microbial ecosystems. Broader Impacts. The results of this project will be valuable to researchers studying biogeochemical patterns at both fossil and modern methane seeps. The dissemination plan calls for the development of a DVD/CD-ROM for educators that will open up the dynamic and complex world of microbial-sediment interactions in methane seeps to a broad audience. This research will provide critical primary research experience for at least four undergraduate students who will be involved in all aspects of the research including formulation of field strategy, laboratory analysis, and preparation of manuscripts. The students will gain an appreciation for collaboration through the experience and teaching workshops, and the project will broadly impact the undergraduate research capabilities and teaching pedagogies of the PIs.