The Ecological Study Of Phytoplankton In Ergis River Watershed And The Adjacent Inland Reiver Basins

This thesis is based on the seasonal investigation of the phytoplankton community in Ergis River Watershed, Ulungur River Basin as well as Lasite River Basin during normalwater period, low water level period and high flow period. The pattern of spatial and temporal variation of the species composition, the dominant species, the cells density of phytoplankton were analyzed based on the data from 16 sampling stations in three different watershed in Xinjiang. We attempt to gain insight into the environmental factors influencing phytoplankton composition by analyzing the correlativity between the changes characteristics of phytoplankton community and the environmental factors, to serve as a useful baseline and data for the water resources utilization prevention of water environment in Altay of Xinjiang. The main results are as follows:1. A total of 429 phytoplankton species was detected, which belonged to 192 genera, 8 phyla. There were 294 phytoplankton species belonged to 115 genera of 8 phyla in Ergis River Watershed. The phytoplankton composition was dominated by Chlorophya and Bacillariophyta and their species numbers were 36 species belonging to 42 genera and 111 species belonging to 36 genera, respectively. In the Inland River Basins, there were 254 phytoplankton species belonging to 105 genera of 8 phyla. Among them, the phytoplankton composition was also dominated by Chlorophya and Bacillariophyta, which species numbers were 93 species belonging to 41 genera and 87 species belonging to 28 genera, about 36%and 34% respectively. The numbers of species to other phyla were quite low.2. The changes of species numbers which were collected in different sampling seasons in Ergis River Watershed were significant with the annual pattern: high flow period (198 species) > normalwater period (127 species) > low water level period (91 species). The spatial characters of the changes in phytoplankton species number were shown as the pattern of downstream > upstream > midstream. The species numbers of phytoplankton in the Inland River Basins were less than that in Ergis River Watershed. The pattern of the changes in species numbers of phytoplankton in Inland River Basins were shown as high flow period (160 species) > normalwater period (123 species) > low water level period (81 species).3. The dominant species throughout the sampling seasons in Ergis River Watershed was Chlorella vulgaris which belonging to Chlorophyta. The dominant phyla in normalwater period was Cyanophyta, and then it was evolved into Cyanophyta-Chlorophyta during low water level period, in high flow priod the dominant phyla turned into Bacillariophyta. The spatial characters of the species dominance shown as the pattern of Cyanophyta in both of the upstream and the downstream, and Cyanophyta and Chlorophyta were the dominant species of the midstream. The dominance of the dominant species in Inland River Basins were changed in the pattern of normalwater period > high flow period > low water level period. And the dominant species during normalwater period in Inland River Basins was Chlorophyta, then it was evolved into Cyanophyta in low water level period. The dominant species belongs to Cyanophyta and Chlorophyta in high flow period.4. The cells density of phytoplankton in Ergis River Watershed was highest in normalwater period, and least in low water level period. In the same sampling stations, Cyanophyta showed the highest cell density in both normalwater period and low water level period and Chlorophyta was the highest phyla of the cell density in high flow period. The cell density of phytoplankton in Inland River Basins showed the characters of normalwater period > low water level period > high flow period.5. The variation tendency was quite different between different sampling stations. Three different biodiversity index were used to show the biodiversity of phytoplankton in the thesis. Shannon-Wiener diversity index (H), Marglef's diversity index (D) and Pielous evenness index (J) showed the variation range of 1.73~2.45, 0.84~1.38 and 0.51~0.77 in each sampling station in Ergis River Watershed. The water was evaluated as light polluted to moderate polluted watershed according to the diversity index evaluation standards of water quality. However, the evaluation ranges of three diversity index are 1.03~2.67, 0.73~1.57 and 0.38~0.76 in Inland River Basins. The variation tendency and the result of the water quality evaluation were the same as that in Ergis River Watershed. 6. The main influenced environmental factors to the biodiversity indexes of phytoplankton in Ergis River Watershed were altitude, NH4-N, NO2-N, Cla a and the cell density of phytoplankton, which was analyzed by SPSS. In Inland River Basins, the main influenced environmental factors are species numbers of zooplankton, species numbers of phytoplankton, conductivity, salinity and dissolved oxygen.7. The 16 sampling stations in different watershed can be separated into 7 clusters by the means of cluster analyze and MDS use the seroean similarity coefficient data. This was a hypothetical block form.8. Canonical correspondence analysis (CCA) was used to investigate the environment phytoplankton relationship. The results of CCA showed that Cla a, latitude, zooplankton density, temperature and COD was highly correspondence to axis 1. The numbers of phytoplankton species and density in different watershed in Altay will increase with the increasing of temperature. Besides this, salinity, altitude, pH, latitudes and longitudes were significant influenced the composition and species of phytoplankton in different watersheds in Altay.