Temporal and spatial variations of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) in the East China Sea and the Yellow Sea

Temporal and spatial distributions of dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) were determined in the East China Sea and the Yellow Sea during June–July, 2006 and January–February, 2007. The concentrations of DMS and total DMSP in surface water in the study area were 5.64 (1.79–12.24) and 28.25 (13.98–44.93) nmol L−1 in summer, and were 1.79 (1.02–3.51) and 11.01 (6.90–17.98) nmol L−1 in winter, respectively. The distributions of DMS and DMSP in the study area were obviously influenced by the Yangtze River effluent and the Kuroshio water. Even under highly variable hydrographic conditions, a significant relationship was observed between DMS and chlorophyll a concentrations in summer as well as in winter, suggesting that phytoplankton biomass might play an important role in controlling DMS distribution in the study area. The summer ratios of DMS/chlorophyll a and DMSP/chlorophyll a were approximately twofold higher than winter values, corresponding with the temporal variation in phytoplankton community structure between summer and winter. The sea-to-air fluxes of DMS were estimated to be 5.32 and 11.92 μmol m−2 d−1 using the equations of Liss and Merlivat (1986) and Wanninkhof (1992), respectively.

▶ The distributions of DMS and DMSP in the ECS and the YS are obviously influenced by the Yangtze River effluent and the Kuroshio water, exhibiting large seasonal and spatial variability. ▶ A good relationship between DMS and chlorophyll a concentrations is found in the study area. ▶ Temporal variations in the ratios of DMS/chlorophyll a and DMSP/chlorophyll a are significantly related to the difference of the phytoplankton composition and abundance between summer and winter. ▶ The emission of DMS from the ECS and YS is estimated.