The effect of temperature on growth characteristics and competitions of Microcystis aeruginosa and Oscillatoria mougeotii in a shallow, eutrophic lake simulator system
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Blue-green algal blooms formed by Microcystis and Oscillatoria often occur in shallow eutrophic lakes, such as Lake Taihu (China) and Lake Kasumigaura (Japan). Growth characteristics and competitions between Microcystis aeruginosa and Oscillatoria mougeotii were investigated using lake simulator systems (microcosms) at various temperatures. Oscillatoria was the superior competitor, which suppressed Microcystis, when temperature was <20°C, whereas the opposite phenomenon occurred at 30°C. Oscillatoria had a long exponential phase (20 day) and a low growth rate of 0.22 day−1 and 0.20 day−1 at 15°C and 20°C, respectively, whereas Microcystis had a shorter exponential phase (2–3 days) at 30°C and a higher growth rate (0.86 day−1). Interactions between the algae were stronger and more complex in the lake simulator system than flask systems. Algal growth in the lake simulator system was susceptible to light attenuation and pH change, and algae biomasses were lower than those in flasks. The outcome of competition between Microcystis and Oscillatoria at different temperatures agrees with field observations of algal communities in Lake Taihu, indicating that temperature is a significant factor affecting competition between Microcystis and Oscillatoria in shallow, eutrophic lakes.
KeywordsMicrocystis Oscillatoria Lake simulator Competition Lake Taihu
This work was supported by the Major State Basic Research Development Program of China (No. 2002CB412301), JICA Taihu Water Environment Restoration Model Project and National Natural Science Foundation of China (No. 40501078). We thank Dr. Fengchang Wu, Dr. Shao Yang and three anonymous reviewers for their useful comments and suggestions.
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