Phytoplanktonic desmids community in Donghu Lake, Wuhan,China

1 INTRODUCTION Donghu Lake (30o33′N, 114o23′E) is a shallow medium sized freshwater lake in Wuhan City, Hubei Province, China and about 5 kilometers away from the Changjiang (Yangtze) River. Before the 1960s, the water surface area was about 27.8 km2. The lake water was clear and the pH ranged from 6 to 7. The shallow area of the lake abounded with macrophytes. The phytoplanktonic and peripheral desmids were very abundant also in this lake. In the late 1960s, Donghu Lake with tota…

Phytoplanktonic desmids community in Donghu Lake, Wuhan, China

For compilation and comparison of desmids flora, the authors restudied the species composition, cell density and biomass of phytoplankton desmids collected at six stations in Donghu Lake at intervals of three months monitored from March of 1956 to February of 1957. A total of 122 taxa belonging to 16 genera were identified from qualitative and quantitative samples. Species ofCosmarium were the most popular ones occupying about 41% of the total species. Based on the observations, the annual mean values of the cell density and biomass were 132.11×10² cells/L and 0.09 mg/L.Cosmarium, Staurastrum, Staurodesmus andClosterium dominated and contributed more than 70% of the total cell density and biomass at six stations in four seasons. The maximum species number, cell density and biomass in autumn revealed that the highest variety (64 taxa, 1296×10² cells/L and 0.889 mg/L respectively) occurred at Station 3 located in the southern part of Donghu Lake. From then on to the mid 1990s the desmids community decreased sharply in Donghu Lake, resulted clearly from eutrophication in the lake.