【作者】 陈明曦；

【导师】 刘德富；

【作者基本信息】 三峡大学 ， 防灾减灾工程及防护工程， 2007， 硕士

【摘要】 本论文以国家自然科学基金资助项目“河道型水库水华生消机制研究”（项目编号:50679038）为依托,从2006年4月至2007年4月,以铜绿微囊藻为供试藻种,研究了不同环境因子、营养因子和水文因子（流速）对蓝藻水华生消的影响。研究结果表明:1、环境因子对蓝藻水华生消的影响（1）pH为8左右可促进藻类的生长,不同处理组水体pH在藻类生长过程中一直发生变化,总体表现出归一化趋势,当t=18-20d时,各处理组pH归趋为8.6～9.9之间。（2）水温从10℃上升到32℃,藻类比增长率增大。藻类比增长率μ（y）与水温WT（x）的回归方程为y=-0.0022x²+0.1356x-1.0208,（R²=0.9833）,由此回归方程可以得出当x=30.82,即水温为30.82℃时,有最大的增长率μ=1.069。（3）随着光强的增大,藻类比增长率增大;藻类比增长率μ（y）与光强I（x）的回归方程为y=-3E-08x²+0.0003x+0.125,（R²=0.9839）,由此回归方程可以得出当x=5000,即光强为5000lx时,有最大的比增长率μ=0.875。（4）随着光照时间的增大,水体中的藻类比增长率增大,光照时间越长,藻类生长越好。2、营养因子对蓝藻水华生消的影响（1）P浓度在0.14-0.62mg/l,铜绿微囊藻繁殖增长较快;根据Monod方程和Droop方程计算得到磷影响铜绿微囊藻生长的比增长率的最大值为μ_max=0.667,半饱和常数K_SP=0.019mg/l。（2）N浓度在1.8-4.1mg/l时,铜绿微囊藻繁殖增长较快;动力学参数计算得到最大比增长率μ_max=0.900,半饱和常数K_SN=0.751mg/l。结果表明:以总磷为限制底物时的半饱和常数K_SP远小于以总氮为限制底物时的半饱和常数K_SN,因此,铜绿微囊藻对P比对N有更好的亲和性,总磷浓度的增加更易促进铜绿微囊藻的生长,诱发蓝藻水华。（3）随着N/P从2增大到383,比增长率先增大再减小;藻类生长的比增长率μ（y）与N/P（x）的回归方程为y=-0.0645（lnx）²+0.3769lnx+0.3363,（R²=0.9398）。由回归方程可以得到当ln（N/P）=2.92时,即N/P=18时,最适宜铜绿微囊藻生长与蓝藻水华的爆发。（4）环境与营养因子的正交试验表明:P=0.8mg/l、N=3.6mg/l、WT=29-30℃、光强为3300-3400lx是铜绿微囊藻生长的最适宜条件;光照强度的改变对铜绿微囊藻生长的影响最为敏感,P营养元素对铜绿微囊藻的影响大于N营养元素。3、水文因子（流速）对蓝藻水华生消的影响（1）小流速试验: 0-11cm/s 5个流速水平组的比增长率μ其变化幅度在0.437-0.657之间,相差不大。在0-11cm/s的流速区间内,不同的流速对铜绿微囊藻的生长和蓝藻水华的生消没有显著的相关性。2)大流速试验:在10、20、30和40cm/s四个流速水平下,藻类一个完整的生长周期约24-28d,水体叶绿素a达到最大值的时间约12-18d,可以初步认为流速增大抑制藻类生长,延缓水华发生;当流速为30cm/s时,藻类比增长率μ最大,初步推断在30cm/s与40cm/s之间存在一个对藻类生长最为有利的临界流速V0,根据比增长率μ（y）与流速V（x）的回归方程:y = -0.0002x² + 0.0146x + 0.0656,（R² = 0.9485）可得到V0=36.50cm/s,此推论还需要进一步的试验验证。更多还原

【Abstract】 According to the item named“Mechnaism of Algal Bloom Formation and Disappearing in River-type Reservoir Firth”which supported by the national Natural Science Foundation of China （No. 50679038）, the paper took M.aeruginos as an example, and studied the effect of environmental conditions, nutrient concentrations and hydraulic dynamics on the blue-green algal bloom formation and disappearing during April 2006 to April 2007.The results showed as following:1. The effect of environmental conditons on the algae growth and bloom formation:（1）The initial pH value at 8 would promote the growth of algae. Under different initial pH value conditions, the pH would be alkalescency along with the growth of algae. The pH would go to be 8.6 to 9.9, after 18 to 20 days when algal began to grow.（2） Along with the rising of water temperature from10℃to 32℃, the multiplied speed of alga will be augmented. The quadratic regression equation used to show the relationship between the multiplied speed of algaμ（y） and the water temperature（x） was y=-0.0022x²+0.1356x-1.0208,（R²=0.9833）. From this equation, we could draw a conclusion that when water temperature was 30.82℃, the maximum of multiplied speed of alga would be 1.069.（3） Along with the irradiation ranged from 50lx to 5300lx, the multiplied speed of alga will be augmented. The quadratic regression equation used which shows the relationship between the multiplied speed of algaeμ（y） and the irradiation（x） was y=-3E-08x²+0.0003x+0.125,（R²=0.9839）. Base on this equation, we found that when irradiation was 5000lx, the maximum of multiplied speed of alga was 0.875.（4） The multiplied speed of alga increased with the light period prolonging. More longer the light period, more quickly the growth of M.aeruginosa.2. The impact of nutrient concentration on the algae growth and bloom formation:（1） It was appropriate for the growth of M.aeruginosa when the P concentration ranged from 0.14 mg/l to 0.62 mg/l. The phorsphor half saturation constant KSP and the multiplied speed of alga were 0.019mg/l and 0.667 seperately based on the Monod equation and Droop equation.（2） It was appropriate for the growth of M.aeruginosa when the N concentration ranged from 1.8mg/l to 4.1 mg/l. The nitrogen half saturation constant K_SN and the multiplied speed of alga were 0.751mg/l and 0.900 seperately based on the Monod equation and Droop equation.Therefor, we found that K_SN was higher than K_SP, which indicated the effect of phosphorus on the growth of M.aeruginosa was further more significant than that of nitrogen,in other words, increase of phosphorus concentration would promote the growth of M.aeruginosa more easily than nitrogen.（3） The multiplied speed of M.aeruginosa risen up firstly, then fall down with the N/P ranged from 2 to 383. The regression equation between the multiplied speed of algaμ（y） and N/P ratios （x） was y =-0.0645x² + 0.3769x+0.3363,（R²=0.9398）. Base on this equation, we drew a conclusion that when N/P=18, the maximum of multiplied speed of alga was 0.875.（4） The orthogonal experiment showed that it was appropriate for the growth of M.aeruginosa when P=0.8mg/l、N=3.6mg/l、WT=29-30℃、irradiation 3300-3400lx; the irradiation condition was the most sensitive to the growth of algae, moreover, the effect of P is stronger than that of N.3 The effects of hydraulic dynamics on the algae growth and bloom formation:（1）Low flow velocity: The multiplied speed of algae changed from 0.437 to 0.657 with the flow velocity from 0 to 11cm/s, which showed that there was unconspicuous difference on the growth of algal and formation of bloom in different flow velocity.（2） Hight flow velocity:When the flow velocity were 10,20,30 and 40cm/s seperately, the life cycle of algae was 24-28d. The time for the occurrence of maximal chlorophyll a concentration was 12-18d. The risen of flow velocity will restrict the growth of algae and stay the formation of bloom. When the flow velocity was 30cm/s, the multiplied speed of M.aeruginosa was the maxiaml value. There maybe has a critical velocity（V₀） between 30cm/s and 40cm/s.Based on the regression equation between the multiplied speed of algaμ（y） and flow velocity V（x）: y = -0.0002x² + 0.0146x + 0.0656,（R² = 0.9485）, we drew a conclusion that V0=36.50cm/s,which will be verified in furture.更多还原