Lin, Yu-ShihYu-ShihLinWei, Chih-LinChih-LinWeiChang, Yuan-PinYuan-PinChangWang, Jih-TerngJih-TerngWangChuang, Shu-YingShu-YingChuangWang, Liang-ChiLiang-ChiWangLiu, James T.James T.LiuLi, Hong-ChunHong-ChunLiHsu, Chieh-WeiChieh-WeiHsu2025-10-302025-10-302025-11https://www.scopus.com/pages/publications/105017885730?origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/733278Continental shelf sediments are a focal point for research on the transport, degradation, and burial of organic matter (OM), yet OM reactivity has rarely been examined within an integrated source-to-sink framework. This study investigates the relationships among source-to-sink processes, surface sediment OM composition, and oxygen consumption rates—used as a proxy for OM reactivity—of the northeastern Taiwan Strait, a passive margin shelf influenced by small mountainous rivers (SMRs). Distinct zonation of OM types was observed across the shelf. Petrogenic OM, the most abundant component, was concentrated in the depocenter, likely transported by hyperpycnal flows. Its association with low total oxygen uptake (TOU) underscores its refractory character. In contrast, fresh terrestrial OM, enriched in nearshore muds via hypopycnal flows or resuspension-advection processes, elevated TOU by nearly threefold compared to petrogenic OM-dominant sediments. As a minor component, marine OM exhibited a spatial distribution consistent with vertical delivery by the biological pump. High benthos-mediated oxygen consumption was found in silty and sandy sediments with the maximum marine OM proportion. Dissolved oxygen uptake showed a strong positive correlation with total hydrolyzable amino acids, derived from both marine and terrestrial sources. The observed connection between OM composition and oxygen consumption is attributed to the high-fidelity delivery of fresh and refractory OM from SMRs, followed by spatial partitioning driven by transport dynamics. The burial efficiency of terrestrial OM on this passive margin shelf was lower than on adjacent active margins, highlighting the critical role of shelf morphology in regulating carbon burial efficiency in SMR-sustained systems.Oxygen consumption ratePassive margin shelfPetrogenic organic matterSmall mountainous riverTotal hydrolyzable amino acid[SDGs]SDG6[SDGs]SDG13[SDGs]SDG14journal article10.1016/j.gca.2025.09.031