Dianchi Lake Sediment Algae Characteristics And Phytoplankton Spatial And Temporal Distribution

This paper studies the composition and characteristics of algae in the sediment through the cultivation experiment, and on the basis of previous studies and comprehensive. Based on statistical analysis of data from previous studies of the temporal and spatial distribution of phytoplankton in Dianchi Lake, and some environmental factors on the growth of algae and Stocks change. The conclusions are :The algae species composition of in the Dianchi Lake sediment is Microcystis.sp, Scenedesmus.sp, Pedias trum.sp, Tetraedron.sp, Staurastrum.sp, Cyclotella.sp, Cyclotella.sp, Melosira.sp, Naricula.sp,and same with phytoplankton species in the Dianchi lake. In the effects of environmental conditions experiment, we found the recruitment rate and abundance of Microcystis was correlated with temperature ,we also found there is no correspondence between the N, P concentration and the recruitment rate or abundance ,the different light cycle also had no direct effect on the recruitment or abundance of Microcystis .The abundance of the Microcystis in Chuhaikou is higher than Caohai and Luojisying.Suggested that the rate of recruitment from sediment to water may be a process of importance in the initiation of algal blooms.Based on the statistical analysis found that seasonal changes of phytoplankton biomass in Dianchi lake :Biomass is usually two peaks in a year, usually in the summer and autumn-winter, the seasonal changes of phytoplankton specices composition: green algae in the Dianchi Lake superiority over the summer. Cyanobacteria superiority over the autumn and winter. diatom were present in the spring. changes in phytoplankton biomass is the overall downward trend. the annual changes in phytoplankton species composition : diatoms and green algae dominated in 1993, 1996, in 2000, 2002, 2005 ,cyanobacteria is the dominant species. The spatial variability in phytoplankton biomass: Caohai>Longmencun>Chuhaikou>Luojiaying . The spatial variability in the algae species composition: diatoms and green algae dominated in Caohai and Luojiaying in 1993 and 1996.. green algae is the dominant species in Chuhaikou,Luojiaying. In 2000, 2002 and 2005 phytoplankton species composition of four sampling points are basically the same, green algal and cyanobacteria were the dominant in four sampling points. Dianchi Lake's cyanobacteria biomass correlated positively with total nitrogen concentration, turbidity (P <0.01).