1. Research Center for Engineering Ecology and Nonlinear Science, North China Electric Power University, Beijing 102206, China;
2. School of Environmental Science and Engineering, Shandong University, Jinan 250100, China;
3. College of Life Science, Shandong Normal University, Jinan 250014, China
The phytoplankton community of Lake Nansihu was investigated seasonally from 2011 to 2014. The effects of phytoplankton diversity (species richness and evenness) on both community biomass and temporal stability were analyzed. A total of 138 phytoplankton species belonging to 78 genera and 8 phyla were identified in the lake. Phytoplankton abundance ranged between 5.09×105/L and 6.95×106/L and its biomass varied from 0.44mg/L to 5.46mg/L in different seasons. In spring and winter when the temperature was low, phytoplankton biomass increased with increasing species richness, phytoplankton community with larger number of species was more productive. In summer when the temperature was high, there was a strong negative relationship between phytoplankton biomass and species richness, phytoplankton community with higher diversity had relatively lower biomass. The stability indices of Cyanophyta, Bacillariophyta and total phytoplankton were all unimodally related to phytoplankton species richness. However, the effects of phytoplankton evenness on the Cyanophyta, Chlorophyta, Bacillariophyta or total phytoplankton stability index were not significant (P>0.05). Results in this research indicated that the effects of phytoplankton diversity on community biomass and temporal stability were complex:species richness had a linear relationship with community biomass and influenced by seasonal variations, a unimodal relationship with temporal stability; evenness had no relationship with either community biomass or temporal stability.
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