Temporal and spatial distributions of carbonyl sulfide, dimethyl sulfide, and carbon disulfide in seawater and marine atmosphere of the Changjiang Estuary and its adjacent East China Sea

Abstract

AbstractCarbonyl sulfide (COS), dimethyl sulfide (DMS), and carbon disulfide (CS2) concentrations were determined in seawater and the overlying atmosphere of the Changjiang Estuary and the adjacent area during two cruises from 22 February 2016 to 15 March 2016 and from 03 July 2016 to 25 July 2016. The concentration ranges of COS, DMS, and CS2 in seawater during winter were 121–388 pmol L−1, 0.321–1.59 nmol L−1, and 10.3–46.8 pmol L−1, respectively, and those during summer were 98–346 pmol L−1, 0.397–9.13 nmol L−1, and 13.3–65.4 pmol L−1. The DMS concentration in surface seawater varied seasonally, whereas the COS and CS2 concentrations varied little. The atmospheric mixing ratios of COS, DMS, and CS2 were 459–777 pptv, 5.2–96.8 pptv, and 96.9–164 pptv during winter and 417–644 pptv, 133–365 pptv, and 15.8–89.8 pptv during summer, respectively. A correlation analysis revealed that COS concentration was related to the concentrations of DMS and CS2. The estimated fluxes of COS, DMS, and CS2 were in the range of 1.19–2.06 μg m−2 d−1, 15.11–164.81 μg m−2 d−1, and 0.27‐1.32 μg m−2 d−1 during winter and 0.61–0.97 μg m−2 d−1, 71.76–2511 μg m−2 d−1, and 0.38–1.47 μg m−2 d−1 during summer, respectively. These results indicate that the study area is a sink for COS, but served as a source of atmospheric DMS and CS2 during the study period.