Chlorophyll Anomaly Triggered by Long-range Transported Dust over the Northern South China Sea

Satellite assessment of the biogeochemical impact of airborne dust deposition into open oceans is hindered by our current inability to retrieve dust properties and ocean color over an extensive period of time, particularly under the influence of cloudy conditions. In this study, we explore the changes of Chlorophyll-a (Chl-a) concentration due to airborne dust fertilization over the northern South China Sea (SCS), which is a cloudy environment with oligotrophic waters in the spring. Multi-year composites from NASA/SeaWiFS Chl-a imagery, in conjunction with a 16-year observational record of dust events, provide a first look at the Chl-a distribution for dust events and the non-dust background during March-April in this region. Our results reveal that the long-range transport of Asian dust to the SCS, although relatively rare (6 cases since 1994), does occur and can significantly enhance phytoplankton blooms. Compared to the western North Pacific, oceanic biogeochemistry in the northern SCS may be much more susceptible to long-range transported Asian dust.