| From December 2007 to Mid-March 2008 , part of water in the Shuanglong Lake, cyanobacterial blooms occurred, it was identified as O.agardhii Gorn and accounting for 95% of algal blooms. In order to explore the prediction of O.agardhii Gorn, We carried out the site surveys from March 2009 to July 2010, studying O.agardhii Gorn's temperature,irradiance and other basic features for establishing Growth temperature and Growth irradiance of the O.agardhii Gorn. Meanwhile, we used the software of matlab7.6.0 to analyze the growth trends of the O.agardhii Gorn for irradiance and temperature, for establishing O.agardhii Gorn's forecasting techniques.First, the main results of the study as follows:1) the composition of algae in Shuanglong Lake in the Spring of 2009: There were abundant species of algae in Shuanglong lake during the period of research. The 8 phyla, 61 genera and 115 species (including varieties) of phytoplankton community in the waters of the ShuangLong Lake were identified: Chlorophyta, Cyanophyta, Bacillariophyta, Cryptophyta,Xanthophyta,Chrysophyta,Pyrrophyta,Euglenophyta. In the spring, the dominant algae species is Chlorophyta and Cyanophyta, and the O.agardhii Gorn ratio of the total 23.13%, accounting for 85.67 percent in the proportion of cyanobacteria.2) The optimum temperature and the optimum irradiance of the O.agardhii Gorn in the Shuanglong Lake:In the Shuanglong Lake,the optimum temperature of the O.agardhii Gorn is 11~19℃in natural conditions, during the study, the algal density reached the maximum at 17.8℃. When Cloudy with low temperatures, the O.agardhii Gorn's algae algal density is lower; but High Strength illumination with high temperatures, the O.agardhii Gorn's algae algal density is increased significantly. In different illumination layers, The algae algal density of the O.agardhii Gorn is different: The algae algal density at depths of 50cm is slightly greater than the surface of the water.3) The trend in biomass of the O.agardhii Gorn in the spring of the Shuanglong Lake:During 2008 to 2010, The trend in biomass of the O.agardhii Gorn is decreasing year by year in spring of the Shuanglong Lake.4) The optimum of growth temperature range and inflection point temperature for O.agardhii Gorn:O.agardhii Gorn has three temperature range for growth: 13~14℃:During the period, O.agardhii Gorn's growth is extremely slow and takes a long time; 14~16℃: During the period,O.agardhii Gorn has a faster growth and a shorter time-consuming, and it reached its peak value around 15℃; 16~17℃:During the period,O.agardhii Gorn's growth is slow and takes a long time. Inflection point temperature of the O.agardhii Gorn is 14℃and 16℃.5) The optimum of luminous intensity for O.agardhii Gorn:To the water which is not shading (direct light): In any temperatures suitable for the growth, during the low light (30W, 550lx), O.agardhii Gorn's growth is slow and takes a long time; During the optimum of luminous intensity(60W,2000lx): O.agardhii Gorn has a faster growth and a shorter time-consuming; During the high light(90W,14650lx): O.agardhii Gorn's growth is slow and takes a long time, and its growth was inhibited.To the water which is shading(light scattered): In any temperatures suitable for the growth, in any light intervals(the low light (30W, 550lx),the optimum of luminous intensity(60W,2000lx); the high light(90W,14650lx)), the growth rate of O.agardhii Gorn is all slow.6) In the Matlab 7.6.0 environment SVM is used to predict the growth of O.agardhii Gorn under 17℃, the error is: -35.4%,-25.82%,9.43%, and the actual value of the errors.Second, the conclusions as follows:1) In the year, algal blooms is not outbreaked, O.agardhii Gorn is not the dominant species of phytoplankton in the Shuanglong Lake.2) O.agardhii Gorn needs lower temperature for the growth in natural water.3) Solar radiation intensity effects the growth rate of O.agardhii Gorn in the Shuanglong Lake.4) Different Illumination layers effect the number of O.agardhii Gorn in the Shuanglong Lake.5) O.agardhii Gorn's pollution is significantly lower in the Shuanglong Lake.6) O.agardhii Gorn has three temperature range for growth: low speed growth period (13~14℃), period of rapid growth (14~16℃), reduced growth period (16~17℃).7) To the growth of algae ,direct light is better than scattering light.8) To the growth of O.agardhii Gorn, 2000lx is suitable for illumination. 9) It is not very accurate in Matlab7.6.0 environment using SVM model to predict algal growth results, and we need to explore new prediction model of algae.
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