[Chlorophyll a content and primary productivity of phytoplankton in Meiliang Bay of Taihu Lake].

Based on the investigations on primary productivity of phytoplankton and related factors at four stations in Meiliang Bay of Taihu Lake from May 1998 to August 1999, this paper studied the distribution of phytoplankton chlorophyll a, its primary productivity, and their relationships with environmental factors. The results showed that there were obvious temporal and spatial differences in chlorophyll a and primary productivity. The high values of chlorophyll a content and primary productivity were recorded in spring and summer. Generally, chlorophyll a content and primary productivity decreased from inner to outer in the bay. The vertical profile of primary productivity showed that the maximum of primary productivity was recorded at 20-50 cm water depth in spring, summer and autumn, while there was no remarkable difference in winter. The primary productivity exponentially increased with water temperature from 10 to 30 degrees C. There was a significant positive correlation between chlorophyll a content and primary productivity. The correlation coefficients between nutrients and primary productivity varied greatly, which presented that nutrient was not the limiting factor for phytoplankton growth. The analysis of P-I curves based on different photosynthesis-irradiance models showed that obvious light inhibition was occurred at surface water in spring and summer.