Microbial Degradation of Refractory Organic Carbon During Rock Weathering

岩石风化过程中难降解有机碳的微生物降解。埃格林顿Petsch海洋化学和地球化学系伍兹霍尔海洋学研究所伍兹霍尔，MA 02543碳循环的一个重要组成部分是有机碳从古代沉积岩转移到海洋和大气中。 在岩石风化和土壤形成过程中，古代沉积有机物的氧化消耗O2并释放CO2，从而在地质时间尺度上对地球大气的组成进行了强有力的控制。 本研究探讨了岩石风化过程中微生物活动在沉积有机质降解和氧化中的作用。 我们已经确定，有微生物生活在浅层地下沉积岩。化合物特定的14 C分析细胞膜脂质被用来建立，在文化中，这些生物同化难熔的，岩石衍生的有机碳作为其碳源。 本研究的未来研究包括：化合物特定的13 C和14 C分析环境样品中的微生物脂质，以确定岩石风化的自然环境中的碳途径。对现场样品和实验室培养物中的微生物进行系统发育分析，以建立群落结构并与已知生物进行比较。微生物细胞与迭代更特异性探针的荧光原位杂交以检查微生物之间的空间关系，风化环境中的有机质和矿物探测器红外光谱提供沉积岩内有机物组成的微观描述和与微生物生长模式的相关性。通过与无菌相比，通过这项研究，将出现一个前所未有的描述微生物活动对岩石风化过程中古代沉积有机物氧化的影响，直接适用于了解全球范围的碳循环和地球大气成分的控制。

AbstractMicrobial Degradation of Refractory Organic Carbon during Rock WeatheringByK.J. Edwards, T.I. Eglinton, S.T. PetschDepartment of Marine Chemistry and GeochemistryWoods Hole Oceanographic InstitutionWoods Hole, MA 02543An important component of the carbon cycle is transfer of organic carbon from ancient sedimentary rocks to the oceans and atmosphere. Oxidation of ancient sedimentary organic matter during rock weathering and soil formation consumes O2 and releases CO2, thus providing a strong control on the composition of Earth's atmosphere over geologic time scales. This study investigates the role of microbial activity in the degradation and oxidation of sedimentary organic matter during rock weathering. We have determined that there are microorganisms living within shallow-subsurface sedimentary rocks. Compound-specific 14C analysis of cell membrane lipids was used to establish that in culture, these organisms are assimilating refractory, rock-derived organic carbon as their carbon source. Future investigations of this study include: Compound-specific 13C and 14C analysis of microbial lipids from environmental samples to determine carbon pathways in nature environments of rock weathering. Phylogenetic analysis of microorganisms in field samples and lab cultures to establish community structure and comparison with known organisms. Fluorescent in-situ hybridizations of microbial cells with iteratively more specific probes to examine spatial relationships between microorganisms, organic matter and minerals in weathering environmentsArray-detector infrared spectroscopy to provide microscale description of organic matter composition within sedimentary rocks and correlations with microbial growth patterns.Analysis of abundance and composition of dissolved organic compounds released through microbial activity compared with sterile controls to contrast rates of oxidation versus dissolution of ancient sedimentary organic matter.From this study will emerge an unprecedented description of the influence microbial activity has on oxidation of ancient sedimentary organic matter during rock weathering, with direct applicability towards understanding of global scale carbon cycling and controls on the composition of Earth's atmosphere.