| To understand the relationship between the spatial-temporal variations of phytoplankton primary productivity and its environmental factors in Dianshan Lake,monthly survey was carried out from April,2009 to March,2010,with the method of white and black bottles. The result shows that seasonal variation of primary productivity (calculated according to carbon,following the same) is summer ［0.95 g·(m3·d)-1］ > winter ［0.83 g·(m3·d)-1］ > spring ［0.77 g·(m3·d)-1］ > autumn ［0.62 g·(m3·d)-1］. From the flat distribution,primary productivity is higher in northern and southern parts than that in east and west,with no significant differences in each point ( p＞0.05 ). From the vertical distribution,phytoplankton light availability is an important limiting factor. Primary production of 0.3 m underwater is higher than that of 0.5 m. However,primary production of 0.3 m level in summer is lower because of light inhibition. Seasonal changes in primary productivity may be due to phytoplankton community structure and replacement of the dominant species. There are significantly positive correlation between Chlorophyll a (Chl-a) and phytoplankton density with primary productivity (p < 0.01),and Chl-a has better correlation with primary productivity. Phytoplankton biomass shows a positive reaction to its productivity and may preliminary provide a reference for the number of phytoplankton. |
