Sources and radiocarbon ages of aerosol organic carbon along the east coast of China and implications for atmospheric fossil carbon contributions to China marginal seas

TitleSources and radiocarbon ages of aerosol organic carbon along the east coast of China and implications for atmospheric fossil carbon contributions to China marginal seas
Publication TypeJournal Article
Year of Publication2018
AuthorsYu, M, Guo, Z, Wang, X, Eglinton, TIan, Yuan, Z, Xing, L, Zhang, H, Zhao, M
JournalScience of The Total Environment
Volume619-620
Pagination957 - 965
Date PublishedJan-04-2018
ISSN00489697
KeywordsAEROSOLS, China marginal seas, Fossil carbon, Radiocarbon (14C) tracer, Total organic carbon
Abstract

Aerosol deposition is an important mechanism for the delivery of terrestrial organic carbon (OC) to marginal seas, but OC age characteristics of aerosols are not well constrained and their contributions to sediment OC burial have not been quantified. Total suspended particle samples were collected along the east coast of China at Changdao (CD), Qingdao (QD) and Huaniao Island (HNI), and were analyzed for total organic carbon (TOC) isotopes (13C and 14C) in order to bridge this information gap. TOC δ13C and Δ14C values ranged from − 23.6 to − 30.5‰, and − 153 to − 687‰, respectively, with the latter corresponding to 14C ages ranging from 1280 to 9260 yr. Estimated contributions of fossil carbon to TOC based on 14C mass balance approach ranged from 26 to 73%, with strong seasonal variations in fossil carbon observed at CD. Fossil carbon at CD showed the highest proportion (73%) in winter, reflecting anthropogenic emissions and the lowest proportion (26%) in summer, caused by biomass contribution (annual ave., 52% ± 17%). In contrast, the fossil carbon at both QD (57–64%) and HNI (57–67%) dominated throughout the year, reflecting local anthropogenic influences and long-range transport. Mass balance estimates indicate that atmospheric deposition and riverine export accounted for 31% and 69% of fossil carbon inputs to the China marginal seas (CMS) respectively, with fossil carbon burial efficiencies approaching 100% in the CMS. On a global scale, an atmospheric fossil carbon deposition flux of 17.2 Tg C yr− 1 was estimated, equivalent to 40% of the estimated fluvial flux to the ocean, and potentially accounting for 24–41% of fossil OC burial in marine sediments. Therefore, the atmospheric deposition constitutes an important source of fossil carbon to marine sediments, and could play a key role in regional and global scale OC budgets and biogeochemical cycles.

URLhttps://linkinghub.elsevier.com/retrieve/pii/S004896971733259X
DOI10.1016/j.scitotenv.2017.11.201