大河影响下的陆架边缘海是有机碳的主要沉积区，在全球碳的生物地球化学循环中发挥着重要作用。受频繁的物理改造作用等影响，该区沉积的有机碳并没有得到很好的保存，而是发生了显著的再矿化分解，但是对其具体过程和机制了解还很少，制约了对区域碳循环过程的深入认识。本项目以长江口-东海内陆架，特别是泥质沉积区为主要研究对象，通过对沉积物进行厌氧培养实验，分析间隙水中溶解无机碳、溶解有机碳及其稳定同位素、氧化还原敏感元素、常量离子等参数，并结合沉积物比表面积、微生物丰度与群落组成和关键功能基因分析等，阐明长江口-东海内陆架泥质区沉积有机碳的再矿化速率、过程和机制及其对有机碳保存和自生矿物形成的影响。通过以上研究，揭示泥质沉积物中的有机碳再矿化在大河影响下的陆架边缘海元素循环中的独特作用，丰富和深化对边缘海碳汇的认识。

River dominated ocean margins (RiOMars) are the major depocenter of organic carbon and play an important role in global biogeochemical cycle of carbon. Effective remineralization of sedimentary organic carbon (SOC) occurs in these systems instead of efficient preservation due to frequent physical reworking of sediments in the upper layer. However, the processes and controlling mechanisms of SOC remineralization remain poorly constrained, which hinder the deep understanding of the regional carbon cycle. In this project, dissolved inorganic carbon (DIC), dissolved organic carbon (DOC) and their stable carbon isotopes, redox-sensitive elements, and major ions in pore-water of time-series incubated sediments, as well as the specific surface area (SSA) and the abundance, community composition and key functional genes of microorganisms in sediments collected from the Changjiang Estuary and East China Sea inner-shelf, especially the mud areas, will be analyzed to better constrain the rates, processes, and mechanisms of SOC remineralization and its impacts on SOC preservation and authigenic mineral formation in this region. Implementation of this project will help to reveal the unique role of SOC remineralization in biogeochemical cycles of elements in RiOMars, and enrich and deepen the knowledge of marginal seas as carbon sinks.