The semi-enclosed nature of East Sea (ES) of the northwestern Pacific Ocean having subtropical and subarctic circulations bounded by the subarctic front encompasses complex physical, biological and chemical processes associated with the formation of numerous recurring eddy features (Fig. 1). These eddies occur at different time scales and have a large influence on the spatial and temporal dynamics of phytoplankton blooms in the East Sea. The present study analyzes these phenomena using SeaWiFS and AVHRR as well as in-situ data Concurrently, hydrographic parameters measured with the CTD sensors are used to elucidate physical factors affecting the spatial distribution and abundance of phytoplankton blooms. Horizontal distributions of potential temperature () and salinity of water off the eastern coast show cold and low saline surface water along the coast and warm and high saline subsurface water offshore, indicative of the northward flow of East Korean Warm Current (EKWC), which deserves important focus as a recurring and energetic feature influencing the dynamics of mesoscale anticyclonic eddy fields in the central East Sea. The process of formation and decay of such eddies often produce interior upwelling that shoals and steepens the nutricline, enhancing phytoplankton population by advection or diffusion of nutrients. The enhanced Chl-a concentration associated with these eddies are attributable to populations of dinoflagellates and diatoms because the region of the eddy formation appears to be strongly connected with EKWC and NKCC waters.