The biogeochemical interactions and feedbacks between the ocean and the atmosphere affect and are affected by climate and environmental changes. I have been studying the variability of chemical composition and behavior of marine atmospheric aerosols from the biogeochemical point of view since the early 1980's. My contributions to our understanding of atmospheric aerosol processes are reviewed briefly here: Anthropogenic and mineral dust aerosols from the Asian continent are found to be transported over the large area of the North Pacific Ocean and to affect the global radiation budget and climate. Atmospheric transport of the aerosols, their chemical and physical interactions and scavenging processes within the marine boundary layer are explained in detail. The impact of atmospheric deposition flux over the sea surface is also found to strongly influence chemical and biological processes in water column and affect rates of marine biological activities. Marine aerosol properties could be altered by feedbacks from marine biological and physical processes. To achieve the quantitative understanding of the linkages among the ocean, the atmosphere and climate, it is necessary to collaborate with community of marine biology, physical oceanography, meteorology and modeling. Finally, I am indeed honored to have been selected to receive the 2009 Oceanographic Society of Japan Award.

The biogeographic characteristics and interannual variation of diatom and silicoflagellate floral fluxes are outlined in the western North Pacific, the Bering Sea, and the Arctic Ocean, based on the time-series sediment trap studies at Stations NAP10t, AB, SA, 50N, K2, KNOT, 40N, and S1. In this paper, two paleoceanographic studies are also introduced. In the paleoceanographic study in the Bering Sea for last 4 million years, long term cooling trend were inferred from the assemblage secession of major diatoms and silicoflagellates. As the another paleoceanography topic, it was estimated by silicoflagellate fossils that the sea surface condition in the middle Eocene Arctic Ocean (ca.45－50Ma) were relatively warm and isolated from other oceans such as the North Atlantic.