Characteristics of Chlorophyll Fluorescence of Microcystis aeruginosa at the end of overwintering in Taihu Lake, China

摘要

Algal chlorophyll fluorescence can be expressed as the photosynthetic potential directly. In order to recognize the photosynthetic activity of Microcystis aeruginosa in the period of overwintering, the chlorophyll fluorescence and algal biomass in different sites of Taihu lake was studied. Based on the data of maximal photochemistry efficiency of PSⅡ(Fv/Fm) , excitation capture efficiency of PS Ⅱ (F′v/F′m) , quantum efficiency of PSⅡ(ΦPSⅡ) , maximum relative electron transfer rate (rETRmax), results show that, horizontally, the four parameters of Microcystis in the Center were the highest, the following is those in Gonghu bay, Meiliang bay, and the lowest in Zhushan bay. There was significant difference between the western part and the southern part (p＜0.05). Vertically, those four parameters in 1.0m depth were the highest among the different depth in water column (p＜0.05), The maximum electron transport rate in rapid light curve in the center, Meiliang bay and Gonghu bay was about 1435μmol m-2s-1 and in Zhushan bay, the western and southern part was about 676μmol m-2s-1 of photosynthetically active radiation. Whereas for the biomass of Microcystis, horizontally, it is higher in the Center and western part than other stations (p＜0.05). Vertically, there is no remarkable difference among all water layers (p ＞ 0.05). It is concluded that Microcystis in the middle level of water showed the higher photosynthetic activity, and concentrated in the center and western part of Taihu Lake. It showed the higher photosynthetic activity in the center than other places during the overwintering period. It could be deduced that Microcystis in the center area of Taihu Lake played an important role in its recruitment.