The characteristics of sedimentary organic carbon in the mud area in the western North Yellow Sea since the Holocene

The sedimentary environment of the mud area in the western North Yellow Sea is stable, and the sedimentary record is continuous, making it an excellent proxy for reconstructing paleoenvironment of the local region and surrounding watershed. Previous researches on the sedimentary organic carbon in the mud area are limited to its modern distribution characteristics through surface sediment analysis, and works on the long-term sedimentary processes and mechanisms of organic carbon remain insufficient. Core W03 in the mud area was used to reconstruct the sedimentary environment of organic carbon since the Holocene using sedimentary total organic carbon index, and to clarify the impact of climate and oceanic environmental changes on the source and deposition of organic carbon. During the period of sea level rise stagnation (10.3～9.8 cal.kaBP), a hard clay layer was developed rich in terrestrial organic carbon (60.7%). The turbulent sedimentary environment resulted in a relatively low total organic carbon content (average of only 0.22%). During the period of sea level rising (9.8～7.0 cal.kaBP), marine-sourced organic carbon (47.7%) boomed in a relatively stable sedimentary environment, which was conducive to the burial of organic carbon. Since the high sea level period (7.0 cal.kaBP to present), the Yellow Sea circulation system has been formed gradually, and the input of terrigenous organic carbon has changed correspondingly with the change of coastal current intensity under the East Asian winter monsoon scheme. The contribution of marine organic carbon was increased continuously to 50.0%, and so did the content of total organic carbon (0.58%). Therefore, sedimentary organic carbon in the mud area since the Holocene is controlled by sea level fluctuation and the resultant ocean circulation system.