A unique seasonal pattern in dissolved elemental mercury in the South China Sea, a tropical and monsoon-dominated marginal sea

A unique seasonal pattern in dissolved elemental mercury (DEM) was observed in the tropical monsoon-dominated South China Sea (SCS). The DEM concentration varied seasonally, with a high in summer of 160 +/- 40 fM (net evasion 580 +/- 120 pmol m(-2) d(-1), n = 4) and a low in winter of 60 +/- 30 fM (net invasion -180 +/- 110, n = 4) and showed a positive correlation with sea surface temperature (SST). The elevated DEM concentration in summer appears mainly abiologically driven. In winter, the SCS acts as a sink of atmosphere Hg-0 as a result of low SST and high wind of the year, enhanced vertical mixing, and elevated atmospheric gaseous elemental mercury. Annually, the SCS serves as a source of Hg0 to the atmosphere of 300 +/- 50 pmol m(-2) d(-1) (385 +/- 64 kmol Hg yr(-1), similar to 2.6% of global emission in similar to 1% of global ocean area), suggesting high regional Hg pollution impacts from the surrounding Mainland (mostly China). Citation: Tseng, C. M., C. H. Lamborg, and S. C. Hsu (2013), A unique seasonal pattern in dissolved elemental mercury in the South China Sea, a tropical and monsoon-dominated marginal sea, Geophys. Res. Lett., 40, 167-172, doi:10.1029/2012GL054457.