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陆架边缘海沉积物是重要的生物地球化学反应器,海洋中90%以上的有机质沉积于此并在早期成岩作用过程中矿化。其矿化路径包括有氧呼吸、反硝化、锰氧化物还原、铁氧化物还原、SO42-还原和CO2还原,并按生成自由能减少的顺序依次发生,构成理想的氧化还原序列。定量研究有机碳矿化路径及其对有机质矿化的相对贡献对揭示能量分配和碳循环具有重要的生态学和环境学意义,也是揭示铁、硫、磷及许多氧化还原敏感性微量组分生物地球化学循环的基础。介绍了海洋沉积物中有机质早期成岩矿化路径的主要特点及不同路径对有机质矿化的相对贡献,重点阐述了长期被忽略的铁锰氧化物异化还原路径的研究进展。总体而言,在远洋深海沉积物中,有氧呼吸是有机质矿化唯一的重要路径;而近海沉积物中,铁异化还原和SO42-还原是最主要的厌氧矿化路径,其中SO42-还原占(62±17)%。从远洋深海到近海陆架,沉积物中有氧呼吸和SO42-还原对有机质矿化的相对贡献具侧向分带特征。最近的反应—传输模拟表明,在全球尺度上,有氧呼吸、反硝化、铁异化还原以及SO42-还原对有机质矿化的相对贡献分别为15%、6.2%、2.8%和76%。
The marine sediments on the margins of the shelf are important biogeochemical reactors. Over 90% of the organic matter in the oceans is deposited here and is mineralized during the early diagenesis. Its mineralization path includes aerobic respiration, denitrification, manganese oxide reduction, iron oxide reduction, SO42-reduction and CO2 reduction, and occurs in decreasing order of free energy of formation to form an ideal redox sequence. Quantitative studies of the pathways of organic carbon mineralization and their relative contribution to mineralization of organic matter have important ecological and environmental implications for revealing energy distribution and carbon cycling as well as revealing that trace elements such as iron, sulfur, phosphorus and many redox-sensitive trace component organisms Geochemical cycle of the foundation. The main features of early diagenetic mineralization pathways of organic matter in marine sediments and the relative contribution of different pathways to the mineralization of organic matter are introduced. The progress in the long-neglected ferrous manganese oxide dissimilatory reduction pathway is also described. Overall, aerobic respiration is the only important path for organic mineralization in deep ocean sediments. In offshore sediments, iron dissimilatory reduction and SO42- reduction are the most important anaerobic mineralization pathways, of which SO42- reduction Accounting for (62 ± 17)%. From the deep ocean to the shelf, the relative contribution of aerobic respiration and SO42- reduction in sediments to the mineralization of organic matter has lateral zoning characteristics. Recent reaction-transport simulations show that on the global scale, the relative contributions of aerobic respiration, denitrification, iron dissimilatory reduction and SO42-reduction to organic mineralization are 15%, 6.2%, 2.8% and 76%, respectively.