Microbial Degradation of Refractory Organic Carbon During Rock Weathering

难熔有机碳在岩石风化过程中的微生物降解作者：K.J.Edwards，T.I.Eglinton，S.T.Petch海洋化学和地球化学系伍兹霍尔海洋研究所，马萨诸塞州伍兹霍尔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。古代沉积有机质在岩石风化和土壤形成过程中的氧化消耗O2并释放二氧化碳，从而在地质时间尺度上对地球大气的组成提供了强有力的控制。本研究探讨微生物活性在岩石风化过程中沉积有机质降解和氧化过程中的作用。我们已经确定在浅层-地下沉积岩中有微生物生活。细胞膜脂的化合物特异性14C分析表明，在培养中，这些生物正在同化难消化的、来自岩石的有机碳作为其碳源。这项研究的未来研究包括：对环境样品中的微生物脂肪进行化合物特有的13C和14C分析，以确定岩石风化自然环境中的碳途径。对野外样本和实验室培养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。将微生物细胞与更具特异性的探针进行原位荧光杂交，以研究风化环境中微生物、有机物和矿物之间的空间关系阵列探测器红外光谱提供了沉积岩中有机质组成的微观描述以及与微生物生长模式的相关性。与无菌对照相比，通过微生物活动释放的溶解有机物的丰度和组成的分析，以对比古代沉积有机质的氧化和溶解速率。从这项研究中，将出现前所未有的关于微生物活动对岩石风化过程中古代沉积有机质氧化的影响的描述，直接适用于理解全球尺度的碳循环和对地球大气组成的控制。

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.