太湖铜绿微囊藻暴发的藻密度预测技术路线的验证

Verification of Technical Route for Density Forecasting of Microcystis aeruginosa in Taihu Lake during Its Bloom

铜绿微囊藻(Microcystis aeruginosa)的繁殖力受低温和高温调控,休眠与生长高温对藻繁殖产生的停止和抑制作用可被诱导低温解除,藻繁殖力恢复程度取决于诱导低温的强度和作用时间,藻繁殖力恢复程度越高,其繁殖速率越大。基于铜绿微囊藻春化作用原理,提出了该藻暴发的藻密度预测技术路线(初春现场采藻分析预测用增长率→藻暴发的预报温光出现时现场采藻计数→预测藻暴发的藻密度),用于指导分析未来最适温光出现时太湖铜绿微囊藻是否暴发这一预测工作。对该藻密度预测的技术路线可行性进行了验证,用3个标准评价预测结果。验证结果为:(1)8个实验组的预测用增长率预测的藻密度与生长的藻密度相关性显著,表明预测用增长率测试合理;(2)在对应预测的6 d中,8组中有5组的预测结果准确性指数I≥0.6,即预测结果在生长藻密度的60%~140%以内,表明大多数预测结果的准确性较好,满足了评价标准一;(3)7 d预测结果有效变化范围的下限为M=(62%~67%)Mt、上限为M=(133%~138%)Mt时,占81%的有准确性预测结果的出现几率Q≥62.5%,满足了评价标准二;(4)预测结果有效变化范围的下限为M=(60%~66%)Mt、上限为M=(134%~140%)Mt时,有准确性的、出现率≥60%的预测结果连续出现天数为6 d,满足了评价标准三;(5)当预测结果偏差范围为(100%±33%),有准确性预测结果的出现几率降低12.5%,连续出现天数为2 d。验证可知,在预测时长为6 d内,有准确性的预测结果有比较高的出现几率是可控的,而不是随机的,预测技术路线指导太湖铜绿微囊藻暴发的藻密度预测是可行的;调高预测结果准确性指数或延长预测时长,预测风险将会增大。

Reproductive capacity of Microcystis aeruginosa is regulated by temperature.High temperature for growth can depress its rapid multiplication.And high temperature of dormancy may even make the multiplication ceased.However,both of the two effects can be relieved by low inducing temperature.The recovering degree of reproductive capacity largely depends on the intensity and time of low inducing temperature which Microcystis aeruginosa is exposed.Greater recovery of reproductive capacity meants a faster multiplication for Microcystis aeruginosa.Based on the principle of verbalization in Microcystis aeruginosa,technical route for density forecasting of Microcystis aeruginosa during its bloom was proposed.At the beginning of spring,samples of Microcystis aeruginosa need be collected from the site and analysed growth rate for forecasting.When forecasting of temperature and light suitable for its bloom,samples of Microcystis aeruginosa need be collected from the site and counted in density.Finally,density of Microcystis aeruginosa is forecasted during its bloom.The technical route for forecast is to analyze whether Microcystis aeruginosa in Taihu Lake will outbreak in the optimum temperature and light.Purpose of this study is to verify the feasibility of technical route,and evaluate the forecasting results.Results of the experiments were as follows,(1)There was a significant correlation between the density of Microcystis aeruginosa forecasted by growth rate and the density measured in eight experimental groups,indicating that the growth rate for forecasting was reasonable.(2)There were 5 experimental groups whose accuracy index of forecasting(I)was more than 0.6 in 8 groups during 6 days,which represented that most of the forecasting results were 60%~140%of the density measured,according with the evaluation standard one.(3)As the lower limit of variation range of forecasting results were M=(62%~67%)Mt and upper limit were M=(133%~138%)Mt in 7 days,nearly 81%of the forecasting results had an occurrence rate of forecasting(Q)more than 62.5%,according with the second evaluation standard.(4)As the lower limit of variation range of forecasting results were M=(60%~66%)Mt and upper limit were M=(134%~140%)Mt,the density of consecutive days with accurate forecasting and Q more than 60%was 6,according with the third evaluation standard three.And(5)when deviation range of forecasting results were(100%±33%),the probability of accurate forecasting results was reduced by 12.5%.And the density of their consecutive days was 2.Above analyses indicates that within 6 days of forecasting,the occurrence rate with accurate forecasting results is relatively high and controllable,rather than random events.It is feasible to forecast the density of Microcystis aeruginosa in Taihu with the technical route above during its bloom.And if the accuracy index of forecast is increased or the days are prolonged,forecasting risk will be increased as well.