Marginal seas are essential reservoirs for terrestrial organic carbon (OC) transported by riverine systems. Knowledge on the burial efficiency of terrestrial OC in these environments is critical for evaluating the current and future potential of marginal seas as carbon sinks. However, the spatial and temporal variability of this efficiency, along with its controlling mechanisms, remain poorly understood. In this study, we analyzed total organic carbon (TOC) and its stable carbon isotopes (δ¹³C_TOC), total nitrogen (TN), terrestrial biomarkers (long-chain n-alkanols), and mineralogical parameters from sediment core A01-B to investigate the burial history of terrestrial OC in the southern Yellow Sea (YS) over the last 10.3 kyr. Using an end-member mixing model based on TOC/TN ratio and δ¹³C_TOC, we quantified the terrestrial OC. Furthermore, its burial efficiency we calculated by assessing the loadings of both long-chain n-alkanols and calculated terrestrial OC. Our results indicate that terrestrial OC delivered by the Yellow River has been effectively sequestered in the southern YS, exhibiting relatively high values during the periods of 7–5 ka and 3–0 ka and low values during the 10–7 ka and 5–3 ka intervals. From 10 to 7 ka, the sea-level rising induced extension of the transport pathway resulting in rapid decrease of terrestrial OC burial efficiency. However, during the stable high sea-level condition (7 ka to present), the interaction and succession of the Yellow Sea Cold Water Mass (YSCWM) and the East Asian Winter Monsoon (EAWM) enhanced and modulated the terrestrial OC preservation. During 7–5 ka, the expansion of the YSCWM created the stable environment with low oxygen and low temperature conditions that favored terrestrial OC preservation, thereby enhancing burial efficiency. In contrast, the contraction or southward migration of the YSCWM during the 5–3 ka led to a decline trend in terrestrial OC burial efficiency. After 3 ka, the YSCWM stabilized in its modern configuration, while an intensified EAWM reduced the oxygen exposure time of terrestrial OC during lateral transport along the shelf, ultimately increasing burial efficiency. This study provides valuable insights into the dynamic response of terrestrial OC preservation to deposition environment and climate change in marginal seas.

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