Abstract: Using HPLC-CHEMTAX method, pigments data collected from the nearshore surface water of the East China Sea in spring of 2008 were analyzed for understanding phytoplankton community structure and relationships with environmental factors. Results showed that the dominant groups are diatoms and dinoflagellates, which averagely contributed to chlorophyll a (Chl a) up to 42% and 32%, respectively. Both diatoms and dinoflagellates preferred in the environment with lower temperature, lower salinity, and higher N/P ratio, but the diatoms bloom occurred in the salinity front formed by the interaction of the Changjiang diluted water and the open ocean water which is higher in salinity and lower in temperature and N/P ratio, while the dinoflagellates bloom occurred in the temperature front formed by the interaction of the Changjiang diluted water and the Taiwan Warm Water which is higher in temperature, lower in salinity and N/P ratio. LOWESS results revealed that both Chl a and dinoflagellates increased incipiently and then decreased as temperature or salinity increasing, while relationships between diatoms and temperature or salinity showed a larger fluctuation. Both Chl a and diatoms increased as N/P ratio increasing, while the relationship between dinoflagellates and N/P ratio displayed a larger fluctuation.

Key words: phytoplankton community, chlorophyll a, spring bloom, environmental factor, nearshore of the East China Sea