title: Contribution of petroleum-derived organic carbon to sedimentary organic carbon pool in the eastern Yellow Sea (the northwestern Pacific).
abstract: We investigated molecular distributions and stable carbon isotopic compositions (δ13C) of sedimentary n-alkanes (C15C35) in the riverbank and marine surface sediments to trace natural and anthropogenic organic carbon (OC) sources in the eastern Yellow Sea which is a river dominated marginal sea. Molecular distributions of n-alkanes are overall dominated by odd-carbon-numbered high molecular weight n-C27, n-C29, and n-C31. The δ13C signatures of n-C27, n-C29, and n-C31indicate a large contribution of C3gymnosperms as the main source of n-alkanes, with the values of -29.5 ± 1.3‰, -30.3 ± 2.0‰, and -30.0 ± 1.7‰, respectively. However, the contribution of thermally matured petroleum-derived OC to the sedimentary OC pool is also evident, especially in the southern part of the study area as shown by the low carbon preference index (CPI25-33, <1) and natural n-alkanes ratio (NAR, <-0.6) values. Notably, the even-carbon-numbered long-chain n-C28and n-C30in this area have higher δ13C values (-26.2 ± 1.5‰ and -26.5 ± 1.9‰, respectively) than the odd-carbon-numbered long-chain n-C29and n-C31(-28.4 ± 2.7‰ and -28.4 ± 2.4‰, respectively), confirming two different sources of long-chain n-alkanes. Hence, our results highlight a possible influence of petroleum-induced OC on benthic food webs in this ecosystem. However, the relative proportions of the natural and petroleum-derived OC sources are not calculated due to the lack of biogeochemical end-member data in the study area. Hence, more works are needed to constrain the end-member values of the organic material supplied from the rivers to the eastern Yellow Sea and thus to better understand the source and depositional process of sedimentary OC in the eastern Yellow Sea.
authors.affiliation: Department of Marine Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si, Gyeonggi-do 426-791, South Korea; Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, South Korea. Electronic address: jhkim123@kopri.re.kr.
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Marine Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si, Gyeonggi-do 426-791, South Korea.
authors.forename: Dong-Hun
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Marine Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si, Gyeonggi-do 426-791, South Korea.
authors.forename: Suk-Hee
authors.initials: SH
authors.lastname: Yoon
authors.affiliation: Marine Geology and Geophysics Division, Korea Institute of Ocean Science and Technology, Ansan 426-744, South Korea.
authors.forename: Kap-Sik
authors.initials: KS
authors.lastname: Jeong
authors.affiliation: Department of Marine Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si, Gyeonggi-do 426-791, South Korea.
authors.forename: Bohyung
authors.initials: B
authors.lastname: Choi
authors.affiliation: Department of Marine Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si, Gyeonggi-do 426-791, South Korea. Electronic address: shinkh@hanyang.ac.kr.
authors.forename: Kyung-Hoon
authors.initials: KH
authors.lastname: Shin
mesh_terms: D000473:Alkanes / Q000032:analysis; D002247:Carbon Isotopes / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D019015:Geologic Sediments / Q000032:analysis*; D010140:Pacific Ocean; D010578:Petroleum; D045483:Rivers
chemical_list: D000473:Alkanes; D002247:Carbon Isotopes; D010578:Petroleum
keywords: Carbon isotope; Gymnosperm; Petroleum; The Yellow Sea; n-alkanes