|
Excess nutrients cause eutrophication, resulting in the occurrence of algal blooms. Water blooms occurred in summer and autumn, the most direct manifestation of indicators is algae. Control eutrophication, is to control the source of nutrients, suppress excessive algae growth, to prevent algal bloom phenomenon. Therefore, the study of nutrients, algae, and the relationship between the two lakes in governance has important significance. In recent years, the lake eutrophication problem for a lot of research. Previous research on eutrophication work is carried out under normal temperature conditions, including icing northern regions. In low temperatures and icy conditions on the few studies of eutrophication. For Chagan Lake water quality characteristics and eutrophication problem, there are general research work, both at room temperature (5-9 months) performed. At low temperatures the research work has not been reported. This paper studies the frozen Chagan Lake under the conditions of low temperatures and changes in water quality and eutrophication trends provide a basis for comparison, but also for the protection of Chagan Lake lake environment, provide a basis for controlling eutrophication. In this experiment, Chagan Lake for the study. Chagan Lake is the largest inland lake in Jilin Province, in Daan, dry Bo-shaped alluvial plain, the climate is semi-arid continental monsoon climate, annual average temperature is 4-5 ℃, annual water temperature is 14 ℃ for about 145 days, the winter ice closure period of about 130 days. Chagan Lake water supply mainly depends on the lead channel and lake pine precipitation. The experiment was divided into five collection Chagan Lake ice water samples and samples of water and ice algae, chlorophyll a and nutrients and other indicators were measured. Experimental results show that the Chagan lake was HCO 3 - -Na type water; overall water quality of permanganate index converge; sodium depleted potassium-rich body of water; TN average concentration of 1.98mg / L, total phosphorus average concentration of 0.206mg / L, which according to lake eutrophication of nitrogen, phosphorus indicators can be judged Chagan Lake is eutrophic water bodies. Chagan Lake plane distribution, Chagan deepest lake deep low chlorophyll a concentration area, near the boat dock supplement intakes and low concentration of the position of algae; Chagan Lake in the vertical concentration of algae in the water column decreased chlorophyll a concentration of generally declining; population structure, has been identified belonging to four algae (Cyanophyta, Chlorophyta, diatoms door Euglenophyta) 7 orders, 12 genera of cyanobacteria and green algae Algae Chagan Lake kind. Chagan Lake ice in the melting process, nitrogen salts, phosphate salts and algae in the water content of greater than initial melt melt water content in the whole. Description nitrogen salts, phosphate salts are released into the water first, for the spring revival of algae provide the necessary nutrients. Nitrogen salts, phosphate salts, and the distribution of algae in the ice has a very obvious rule, namely the upper ice nutrients, chlorophyll a and algal concentrations above the lower ice.
|