The Impact Of Thermal Discharge From And Electric Power Plant On Plankton Of Douhe Reservior

The impact of thermal discharge from an electric power plant on plankton of Douhe reservoir (DHR) is discussed in this paper. As a representative multi-functional and shallow reservoir north of china, under the long-term thermal discharge, DHR has heavy thermal impact. And there is lots of information about the aquatic ecosystem of DHR .The results of investigation compared with the historical information can provide reference for the study of similar lakes and reservoirs. This investigation is aimed to research the impact of thermal discharge on aquatic ecosystem through investigation on the plankton of DHR. This investigation is operated in year 2005 and 2006. During the investigation, 170 species of plankton is identified and they are found to belong to 8 phyla, 87 genera. And there are 27 species of plankton belongs to 13 genera Cyanophyta, 72 species of plankton belongs to 41 genera Chlorophyta, 50 species of plankton belongs to 19 genera Bacillariophyta, 4 species of plankton belongs to 2 genera Chrysophyta , 4 species of plankton belongs to 3 genera Xanthophyta, 5 species of plankton belongs to 4 genera Euhlenophyta, 1 species of plankton belongs to 1 genera Cryptophyta, 5 species of plankton belongs to 2 genera Pyrrophyta. According the result, the plankton in the water of DHR is mainly composed of Cyanophyta, Chlorophyta and Bacillariophyta. The zooplankton is mainly composed of Difflugia sp., Centropyxi sp., Trichocerca capucina .sp.and Ascomorpha sp. There are 100 different species of the zooplankton in the water of DHR. Among them, Rotifera, total 37 kinds ofand account for 37% of all categories,has the most category; In addition,Protozoan ,total 33 kinds ofand account for 33% of all categories; Cladocera ,total 16 kinds of and account for 16% of all categories; and Copepoda total 14 kinds of and account for 14% of all categories. Under the influence of thermal discharge of the electric power plant, phytoplankton composition is incline to Chlorophyta-Cyanophyta-mainy type. The density of the population changes with the temperature and the high temperature may lead the life-cycle of the plankton become short.The level of the water eutrophication (take density of phytoplankton as to mainly evaluate index sign) will rise as the raising of the temperature of the water. Also the index of species diversity will debase as the raising of the temperature of the water.From the investigation both within and out of the laboratory, also the model text in lab,we get the conclusion that:1. The thermal impact for plankton mainly represent in: high temperature would probably promote the growth of Cyanophta and Chlorophyta. Also high temperature would expedite the reproducement and shorten the developing period of the phytoplankton.2. The higher temperature would bring an increase amount of phytoplankton but a...