Distribution and source of organic matter in surface sediment from the muddy deposit along the Zhejiang coast, East China Sea

To constrain organic matter compositions and origins, elemental (TOC, TN, C/N) and stable carbon (δ13C) and nitrogen isotope (δ15N) compositions are measured for surface sediments collected from muddy deposit along the Zhejiang coast, East China Sea. The results showed that the TOC, TN, C/N, δ13C, and δ15N were 0.19–0.67%, 0.03–0.09%, 6.76–9.22, −23.43 to −20.26‰, and 3.93–5.27‰, respectively. The δ13C values showed that the mixing inputs of terrigenous and marine organic matter generally dominated sedimentary organic matter in the west part, and the sedimentary organic matters were mainly influenced by the marine organic matter in the east part of the study area. A stable carbon isotope two end member mixing model estimates ~38% terrestrial -derived and ~62% marine-derived inputs to sedimentary organic matter. Microbial mineralization strongly controls δ15N values, and therefore cannot be used to identify the provenance of organic matter for the Zhenjiang coast. •δ13C could effectively identify the provenance of sedimentary organic matter.•Terrigenous organic matter dominated sedimentary organic matter in the west part.•Marine organic matter was mainly from the algal cells in the east part.