Organic carbon in wet deposition of an urbanized coastal bay, North China: Flux, sources and biogeochemical implications

The process of atmospheric organic carbon (OC) entering the ocean through wet deposition plays a crucial role in the global carbon cycle. To gain insights into the biogeochemical dynamics of OC at the land-sea margin, we conducted an extensive four-year investigation on precipitation OC in Jiaozhou Bay (JZB). The results showed that the volume-weighted mean concentration of particulate OC (POC) and dissolved OC (DOC) in precipitation were 0.38 and 2.06 mg C L−1 with an average wet deposition flux of OC for 2666.5 mg C m−2 yr−1. The source of POC in precipitation is predominantly by the C3 plant emission and burning and fossil fuel combustion. Wet deposition contributed 986.6 t yr−1 of OC of which 506.3 t yr−1 of bioavailable DOC, which could have significant implications for carbon cycle in the JZB. This study could enhance the understanding of the marine atmospheric OC in coastal areas. [Display omitted] •Long-term observation of DOC and POC in wet deposition in an urbanized coastal bay•Source apportionment of OC in precipitation in Jiaozhou Bay (JZB)•The atmospheric environment of JZB has showed a gradual improvement in terms of OC.•Wet deposition contributed JZB with sizeable amounts of bioavailable and inert OC.