中文摘要：

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%。

英文摘要：

Continental margin sediments are an important biogeochemical reactor,where 90% of organic matter（OM） is deposited and remineralized.OM remineralization proceeds from the use of O2,NO-3,Mn（IV）-oxides,Fe（III）-oxides,sulfate,and finally CO2 according to the gains of free energy yield,forming an ideal redox sequence.Differentiating various diagenetic pathways and their relative contributions to OM remineralization is of ecological importance for understanding energy partitioning and carbon cycling,and of biogeochemical importance for understanding the cycling of iron,sulfur,phosphorus,and redox-sensitive trace compounds.The main characteristics of diagenetic pathways of OM degradation and their relative contributions,particularly dissimilatory reduction of Fe（III）-and Mn（IV）-oxides,are reviewed.Generally,in pelagic deep sediments,aerobic respiration is the only important pathway for OM degradation;in continental margin sediments,however,anaerobic pathways coupled to dissimilatory reduction of Fe（III）-oxides and sulfate are mainly responsible for OM degradation,with sulfate reduction accounting for averagely（62±17）%.From pelagic deep-sea to continental margin sediments,lateral zonation of the relative contributions of aerobic respiration and sulfate reduction,respectively,to carbon mineralization can be observed.Recent reaction-transport modeling indicates that global-scale contributions of aerobic respiration,denitrification,dissimilatory Fe（III） reduction,and sulfate reduction to OM degradation are 15%,6.2%,2.8%,and 76%,respectively.