[Influence of Periodic Temperature Disturbance on the Succession of Algal Community Structure]

In order to study the mechanism of the habitat disturbance of reservoir on algae blooms, some interior control experiments about the feature of algal diversity and the succession of community structure under different temperature disturbance cycle but the same amplitude condition were conducted, based on the intermediate disturbance hypothesis and combined with algal community habitat selection theory and ecological functional groups of algae. The results showed that:① the intermediate disturbance would accelerate the growth of algae and increase their diversity. Under the gradient of the intermediate disturbance group Δ22℃/48h, the diversity of phytoplankton was the highest, and the biomass reached the maximum, however, without absolute dominant algal species. While in the high frequency disturbance group Δ22℃/24h the biodiversity was relatively lower, but the algae biomass was reduced. ② the periodical change of temperature had obvious influence on the succession of the phytoplankton community, and the dominant species also presented certain differences. The succession of the algal advantageous function group followed the basic rule of X₁(Chlorella)→J(Scenedesmus)→S₁(Phormidium) or X₂ (Chlamydomonas), and the community structure also presented a trend that the C/CR type algae took advantage and the superiority was gradually replaced by R type algae. When the high temperature disturbance was frequent, the R type algae (S₁) was distinctly ascendant. During the experiment, the community structure was given priority to the C/R strategy algae with no or low disturbance. However, the coexistence of algae with different growth strategies was evident in group Δ22℃/48h. Meanwhile, the S strategy algae (L₀) resistant to high temperature stress began to emerge.