Study On Wuliangsuhai Lake Algae Seasonal Variation And Influence Actors

Changes in the number of planktonic algae and replacement of community structure are seasonal. However, environmental factors have very complex influence of planktonic algae, and there are significant differences in different lakes of forms and eutrophications, in the cold and arid regions, and it is typical grass type shallow lakes in the cold and arid regions, it actually is representative. With rapid economic development in recent years, agricultural wastewater, sewage and industrial waste water emissions also increased sharply, resulting in a large number of pollutants discharged into the Wuliangsuhai Lake water quality deteriorated sharply.The paper regards Wuliangsuhai Lake which is grass type shallow lake as the object of study, studies on changes of algae in water in different seasons,and has indoor static test in order to study on environmental factors which affect the growth of algae. From November2012to October2013,10sampling points were set up, to count phytoplankton quantity and species identification. During the investigation,there were314species of planktonic algae in Wuliangsuhai Lake, which belonged to85genera8phylum(including variants). The species composition of algae to the largest proportion was Chlorophyta (32.94%), check out28genera95species, followed by Bacillariophyta and Cyanophyta, respectively check out20genera128species,18genera53species.From the test, it indicates the population of planktonic algae belongs to Chlorophyta-Bacillariophyta-Cyanophyta Type in Wuliangsuhai Lake.As the changes of season, the number of planktonic algae presents Two-Top type. The peak is in May and September. The general characteristic shows Autumn>Spring>Winter>Summer.The alage dominant species of Wuliangsuhai Lake in winter were changed bacillariophyta Synedra, Cyclotella, Navicula, Chlorophyta of Scenedesmus, Euglenophyta of Phacus. In the spring of dominant species has Cyclotella, Oscillatoria, Scenedesmus, Euglena, particularly Scenedesmus obliquus and Scenedesmus acuminatus appear in high frequency, large quantity. In Summer of Chlorphyta and Cyanobacteria as the Dominant Algae, dominant species are mainly Oscillatoria, Phormidium, Chroococcus, Coelastrum, Scenedesmus, Pediastrum. Autumn dominant species were Cyanophyta of Oscillatoria sp., Anabaena sp., Anabaena, Bacillariophyta of Navicula, Nitzschia and Amphiprora ehrenberg.Effects of environmental factors on algae is too high, too low temperature could inhibit the growth of algae, most vigorous growth under the condition of25℃,5℃and30℃algae growth slow. The growth of algae to nutrient absorption performance for the absorption of nitrogen is greater than the absorption of phosphorus. Effect of light intensity on algae showed strong light can promote the proliferation of no illumination, inhibit the growth of algae. Light intensity on algal species changes in the strong light conditions, diatom species decreased rapidly, cyanobacteria increased. Effects of nutrients on algae for the performance of N:P is15:1, the algae cell proliferation is the fastest. High concentrations of nitrogen and phosphorus can inhibit the growth of algae. By different nitrogen, phosphorus concentration on algae growth, found the dependence on N of Wuliangsuhai Lake Algae than on phosphorus dependent.