Abstract: Using the data of suspended particulate matter mass concentration measured in four seasonal cruises of spring in May to June 2011,summer in August 2009,autumn from November to December 2010,and winter from December 2009 to J anuary 2010,seasonal distributions of the suspended organic and inorganic matters in the surface-layer over the shelf of the East China Sea (ECS) were analyzed. The results show that the mass concentration of total suspended particulate matter (TSM) is higher in the winter half year than that in the summer half year, and higher inshore than offshore. The isolines are parallel to the shoreline as a whole. There is a turbid water tongue stretching southeastward with notably seasonal variation near 29°N off Zhejiang Province,and there are two centers of high mass concentration near the Changjiang River Estuary and Yushan Islands of Zhejiang Province and two centers of less high mass concentration centered at 32°N, 125°E and 30°N,127°E respectively all the year round. The high TSM mass concentration front (10 mg/L) is usually parallel to the shoreline. It occurs seasonally near the 40~60 m isobath and often separated into two parts in the northern ECS. The less high TSM mass concentration front (3 mg/L) is not parallel to the shoreline because of a turbid water tongue stretching southeastward all the year round at 29‘N. It appears near the 30~40 m isobath in the northern ECS,near the 50~90 m isobaths in the central ECS, and near the 50~80 m isobath in the southern ECS in different seasons. In contrast, the particulate organic matter (POM) mass concentration is higher in the summer half year than that in the winter half year, Like the TSM, there are two centers of high value and two centers of less high value seasonally. The distribution pattern and magnitude of the particulate inorganic matter (PIM) mass concentration is similar to that of TSM,but the contours shrink shoreward by about 0.5°. There are also two high value centers near the Changjiang River Estuary and off Zhejiang Province, but only one less high value center centered at 32° N, 125° E. The percentage of POM in the TSM from high to low is in the order of spring, summer, winter, fall and it is opposite for PIM.

Key words: continental shelf of the East China Sea, surface layer water, total suspended particulate matter, particulate inorganic matter, particulate organic matter, seasonal distri bution