Program

Atmospheric dust is a possible source of bio-active iron to the high nitrate low-chlorophyll (HNLC) waters, which could result in phytoplankton blooms and enhance the oceanic carbon productivity. Previous studies have shown that atmospheric dust from Asian deserts can be widely deposited in North Pacific. Iron enrichment experiments in the same area prove the importance of iron to stimulate primary production. However, it is still unclear how Asian dust transportation and deposition relate to the iron effect on biogeochemistry in HNLC waters of the Northwest Pacific. In this study, satellite data from MODIS aqua and CALIPSO level 2 retrievals are analyzed to identify the horizontal pathway of Asian dust and vertical distribution of dust concentrations over the ocean. Dust dissolved in water is calculated from deposition rates and soluble dust ratio estimated from a detailed dust model. Daily surface chlorophyll concentrations from SeaWiFS and MODIS are then synchronized with the dissolved dust estimates to find the iron fertilization cases related to the dust supplied iron. Investigations on satellite data and model simulations reveal a close relation between the transportation and deposition of Asian dust and iron effect on carbon productivity in the Northwest Pacific Ocean.