Phytoplankton composition in freshwater ecosystems is varied
and oftentimes includes cyanobacteria and green microalgae as
major components . Furthermore, in some lakes of eutrophication, such as Taihu
Lake in China, Microcystis and Chlorella species were the most
dominant phytoplankton species although their cell densities
fluctuated wildly during the different seasons.
Microcystis spp. was found to be severely limited at temperatures
below 15 8C, and at the preferred
temperature range of 24 to 35 8C .
Chlorella spp. also could tolerate temperatures of 15 to 35 8C, with
optimal temperatures ranges 25 to 32.4 8C for growth. Temperature has been considered as a primary
factor driving Microcystis blooms because high water temperatures
reportedly enhance the distribution and abundance of Microcystis
species to a large extent in eutrophic freshwater ecosystems
. Also, cyanobacteria generally grow better in
higher temperatures than do other phytoplankton
species such as diatoms and green algae . This gives cyanobacteria a competitive
advantage at elevated temperatures. Therefore, global warming
has been suggested to accelerate the expansion of cyanobacterial
blooms .