Spatio-temporal variability and sources of volatile halocarbons in the South Yellow Sea and the East China Sea

Abstract

Abstract Concentrations of volatile halocarbons (VHCs) in surface seawater of the South Yellow Sea and the East China Sea were measured during the summer and winter of 2011. The concentration maxima of CHCl3, C2HCl3, and C2Cl4 were observed in winter, and elevated concentrations of CHBr2Cl and CHBr3 were found in summer. The distributions of VHCs markedly decreased along the freshwater plume from river mouths (such as the Yangtze River estuary) to the open sea. Additionally, the effects of salinity, chlorophyll a, phytoplankton, bacterial abundance, and nutrients on the sources of VHCs were examined. The data showed evidence of spatiotemporal variability and association between the sources of these VHCs and the Yangtze River runoff and biological activity, as well as terrestrial input. The estimated fluxes indicated that the study area acted as sources of VHCs in the atmosphere during the study period.