陆架边缘海沉积物有机碳矿化及其对海洋碳循环的影响

边缘海沉积物是海洋重要的碳储库,其内部的碳循环主要是由有机质矿化分解过程来驱动的。有机碳进入边缘海沉积物后,矿化分解为溶解无机碳(DIC)进入沉积物孔隙水并扩散到上层水柱,参与海洋系统碳循环;同时还有部分DIC与钙镁等离子结合形成自生碳酸盐,保存于沉积物碳库。从生物地球化学角度探讨有机质埋藏机制和效率,在此基础上重点综述沉积物硫酸盐还原、产甲烷和甲烷厌氧氧化过程的耦合机制,以及有机质矿化对自生碳酸盐形成的影响等方面的研究进展,以期加深对陆架边缘海沉积物在全球碳循环收支平衡中的作用及其气候环境效应的认识。

Sedimentary Organic Carbon Mineralization and Its Contribution to the Marine Carbon Cycle in the Marginal Seas

Continental margin sediments are important ocean carbon repository,and the internal carbon cycle is mainly driven by the mineralization processes of sedimentary organic matter. Most organic carbon is transformed to Dissolved Inorganic Carbon(DIC) by mineralization processes after being delivered to continental margin sediments,and DIC from pore water diffuses into the upper water column and participates in the ocean carbon cycle. At the same time,some DIC combines ions such as Ca2+and Mg2+and precipitates as authigenic carbonate minerals so that carbon is stored in the deposits. Based on the biogeochemical study of the mechanism and efficiency of organic matter burial,we discussed the interaction among sulfate reduction,methanogenesis and anaerobic oxidation of methane,and the effect of organic mineralization on the formation of authigenic carbonate.By reviewing the above-mentioned aspects,we can obtain a better understanding of the role of continental margin sediments in the global carbon cycling budgets as well as its climate and environmental effects.