ANNUAL VARIATIONS OF CHLOROPHYLL A AND PRIMARY PRODUCTIVITY IN THE EAST CHINA SEA
ZHANG Yu-Rong;DING Yue-Ping;LI Tie-Jun;XUE Bin;GUO Yuan-Ming;Marine Fishery Institute of Zhejiang Province,Zhejiang Province Key Lab of Mariculture and Enhancement;
We analyzed the seasonal variations in horizontal and vertical distributions of chlorophyll a and primary productivity in the East China Sea based on investigation data collected during 2008––2009. Results show that chlorophyll a(Chl a) concentration in the four seasons from spring to winter was 1.33, 0.93, 1.61, and 0.65 mg/m3, respectively. Generally, maximum Chl a concentration was observed at 0—10m depth in spring, summer, and autumn, but at the bottom in winter. However, in the distant sea, Chl a concentration varied less in season, while in offshore area, vertical variation was observed. The primary productivity of the four seasons was 1375.03, 414.37, 245.45, and 102.60 mg/(m3 h), respectively. Both Chl a concentration and primary productivity were higher than those of the same periods in historical references. The highest average primary productivity was observed in the Yuwai Fishery, and lowest in Haizhou Bay Fishery. In addition, Chl a concentration and primary productivity were significantly positively interrelated. Low temperature in spring and autumn and low salinity in spring and summer were suitable for the growth of phytoplankton. Phosphate may be an important controlling factor to limit Chl a growth in spring and autumn.