| Reservoir is a kind of semi-artificial and semi-natural water body. The main function of the reservoir is water suppling combing ablities with controlling flood, generating electricity and irrigating. The reservoir' s ecological characteristic is very obvious, the current changes the hydrophyte' s growing and distribution in the reservoir directly. The relationship between the species composition, distribution, development and water dynamic is most particular. With the global increasing need of water supply and the effect bringed by humanbeing' s activities to the reservoir' s water quality, carrying out the study of reservoir ecology and its application to the water quality management is being a hot study point in modem limnology.In the reservoir, algae are the primary producers, the algal changes of species and quantity are related to some condition factors. In addtion, they are related to the water trophic level. Nowdays people have noticed the relationship between reservoir and algae, so advanced studies on algae in the reservoir are being carried out.Zhangze Reservoir (113° 10 E, 36°20 N) is located in the Changzhi City, Shanxi Province, North China. The average annual rainfall is ca. 550-650mm (mainly in summer). From April of 1987 to April of 2003, we have sampled five times in the Zhangze Reservoir in order to do quantitative and qualitative researches on algae. Based on the studies, 196 species (induding varieties and forms) of algae were identified, which belong to 5 divisions, 29 families and 62 genera. In the speciesmen of Apr-1987, 104 species (including varieties and forms) have been found comprisingof 19 families, 34 genera. In the speciesmen of Apr-1995, 47 species (including varieties and forms) have been found comprising of 15 families, 22 genera. In the speciesmen of Jul-2002, 23 species (including varieties and forms) have been found comprising of 10 families, 14 genera. In the speciesmen of Oct-2002, 84 species (including varieties and forms) have been found comprising of 17 families, 31 genera. In the speciesmen of Apr-2003, 62 species (including varieties and forms) have been found comprising of 20 families, 32 genera. In addition, we also have used a serial of assessing indexes, such as the saprobic system, biological index and bacillariophyte consult index, to evaluate the water quality of Zhangze Reservoir. From the results we can see that the species number of same month in 1987, 1995, 2003 is different. The species number of Apr-1987 is the most, 104 species. The second is Apr-2003, 62 species. The species number of Apr-1995 is the least, 47 species. In the different seasons in same year the species number is dynamic. The number of Oct-2002 is the most, 84 species. Apr-2003 is the second, 62 species. Jul-2003 is the least, 23 species. From the changes of the cell density, we can conclude that in all the seasons the bioamass of green algae is the most, diatom is the second and the distribution of other algae is very poor. Using the saprobic system, we conclude that the water quality of Zhangze Reservoir is approaching to 3 -mesosaprobic. By the bacillariophyte consult index, the results are in turn 0.11 (Apr-1987), 0.16 (Apr-1995) and 0.56 (Apr-2003), which are continuously increasing, showing that the reservoir's pollution extent is increasing by the year. According to the bacillariophyte biological index , I values are in turn 139, 136, 125, 100 and 33, showing that the quality of the reservoir is changing from clean to mesosaprobic. All indexes indicate that the trophic level of Zhangze Reservoir is transiting from unpolluted to mesosaprobic.The cause of serious pollution is multiplicate, but the key reason is the consistency of nitrogen and phosphorus in the water is increasing what caused by thedrainage of waste water. In addition, the excessive fish culture has some negative effction to the water body. In order to maintain and improve water quality of Zhangze Reservoir, it is essential that the water environment of the valley should be better protected...
|
PDF Full Text Request