【作者】 乔宁宁；

【导师】 李铭红；

【作者基本信息】 浙江师范大学 ， 生态学， 2010， 硕士

【摘要】 水体富营养化是指水体中氮、磷浓度过高,超过水体自净能力,使得水体中某些藻类类群及个体数量增加、透明度下降、溶解氧降低的水质恶化过程。由于目前淡水水体的藻类过度繁殖及水质富营养化问题的突出,开展水体修复技术的研究工作显得尤为重要。本文针对城市居住小区的景观水体面积小、自净能力差的缺点,以生态模拟的方法,选用适宜的水生动、植物种类,用以控制水体中浮游藻类生物量和营养盐含量,达到净化水质的目的。本研究通过对自然条件下水体中浮游生物种类、数量及优势类群的变化情况进行全年监测,研究富营养化水体的形成与水温、溶解氧、pH值、氮磷营养盐等环境因子的相关关系,分析各因子对藻类繁殖过程的影响；并在春、夏季节放养不同密度的滤食性鳙鱼(Aristichthys nobilis)对模拟水体中藻类的取食作用,结合放养过程中生态因子的变化情况探求鳙鱼合理的单种放养密度,以防止水华过度爆发；沉水植物具有很强的吸收功能,植物系统能够有效富集并降解水体中高浓度的营养物质,从而抑制浮游植物生长,提高水体透明度。本研究在藻类密度较高的水体中移栽沉水植物,比较相同生物量的黑藻(Hydrilla verticillata)、苦草(Vallisneria natans)、竹叶眼子菜(Potamogeton malaianus)、微齿眼子菜(Potamogeton maackianus)及菹草(Potamogeton crispus)对水体氮磷的吸收作用及对藻类生物量的影响强度。1. 2008年11月至2009年10月,通过对本地居住小区景观水体的水样监测,共检出藻类8门,55属,其中蓝藻、绿藻以及硅藻是该水体的三大主要门类,占藻类总属数的76.2%；其次,通过对其全年藻类组成及数量来看,浮游植物主要属之间的差异较大。2.本地居住小区景观水体水样的各项生化指标变化具有明显的周期性。总氮浓度的月平均变化范围在0.21-6.78mg/L之间,总磷含量变化范围为0.093-0.547mg/L。与浮游植物生物量(Ta)相关性较大的主要因子是总磷含量(TP),回归方程为：Ta=-123.304+925.208×TP(R=0.654),与总氮相关关系不明显。pH值与水温,溶解氧与pH值及总氮含量等环境因子间也存在显著的相关性。3.在相同条件下放养不同密度的鳙鱼对水体藻类生物量的控制效果不同。放养密度为0.29 g/L时,藻类随时间的逐渐下降,并在实验后期维持在较低的生物量水平；而放养密度在0.57g/L和0.86g/L时,藻类的生物量在放养后期均会出现不同程度的增长。因此将鳙鱼的放养密度控制在0.29-0.57g/L的水平,将会对藻类的控制起到较好的作用。4.从鱼体重与其他因子的相关关系分析结果来看,鱼体重与藻类生物量、总氮、总磷各项指标都呈极显著的正相关。单因素方差分析结果表明,密度为0.29g/L的鳙鱼对藻类的取食作用(p=0.000)和对水质总氮、总磷含量(p=0.006,p=0.000)影响最为显著。5.相同实验条件下通过对五种沉水植物去除营养盐的效率比较可知,总氮浓度的去除率大小顺序为：竹叶眼子菜>黑藻>苦草>微齿眼子菜>菹草；对总磷的吸收率大小依次为：竹叶眼子菜>黑藻>微齿眼子菜>苦草>菹草。6.通过与对照组比较可知,竹叶眼子菜在净化水质及控制藻类方面效果最佳,苦草、微齿眼子菜及菹草净化作用次之,黑藻对水体总磷及浮游植物的去除作用均为极显著(p=0.000,p=0.010),而对总氮含量的作用影响不明显(p=0.209)。更多还原

【Abstract】 Eutrophication is the process of the deterioration of water quality, and that is algal blooms, lower transparency and dissolved oxygen due to the excessive concentration of nitrogen and phosphorus in urban water body. Because of the prominent problem, remediation technology of water environment becomes more important. Small urban landscape water bodies have the shortcoming of small and poor self-purification ability, so under simulated conditions we used two means to control algae biomass and nutrient concentrations in order to purification water by aquatic plants and animal.Using the annual plankton population changes of natural water as contrast, we studied the relationship of water temperature, dissolved oxygen, pH, Total Nitrogen, Total Phosphorus and the other environmental factors, and analyzed the role of every studied environmental factor in the process of algae growth. In the spring and summer, stocking Aristichthys nobilis can effectively prevent from algal blooms. By feeding different densities of the planktivore, we studied it fed on planktonic algae in the simulated water, and combined with the result of the changes of the environmental factor to investigate a reasonable of Aristichthys nobilis’s single-species stocking density.As we known, submerged plants having the ability of absorption, the plant systems can effectively enriched nutrients and then degraded high concentration of nutrients in water. Thus, submerged plants can inhibit the growth of phytoplankton and increase water transparency. In this study, we transplanted submerged plants into the water of high algae density, compared the same biomass of Hydrilla verticillata, Vallisneria natans, Potamogeton malaianus, Potamogeton maackianus, Potamogeton crispus’s absorption of nitrogen, phosphorus nutrients, and its functional intensity on algae biomass.1. We evaluated the present situation of the nature water quality, and 8 phyla,55 genera of phytoplankton were detected from November 2008 to October 2009. Mostly what we had surveyed were Chlorophyta, Cyanophyta and Bacillariophyta, accounted for 76.2% at genera level. Then the analysis revealed the annual of population composition and species number of phytoplankton had a massive difference.2. All the biochemical indicators of the nature water had a remarkable periodicity. Total nitrogen monthly average ranged 0.21-6.78 mg/L, and total phosphorus ranged 0.093-0.547 mg/L. In addition, total algae biomass (Ta) and total phosphorus (TP) had remarkable correlation, and the regression equation:Ta=-123.304+925.208×TP (R=0.654). The relativity was not distinct between phytoplankton biomass and total nitrogen. Between other environmental factors also existed closer correlativity.3. The different controlling effect when the stocking density of Aristichthys nobilis was different, although the condition was the same. The algae decreased with time accumulating when the fish density was 0.29g/L, and kept the lower biomass in the later period. However, when the density of fish was 0.57g/L and 0.86g/L, the algae biomass would reincrease in the later period. So the density of Aristichthys nobilis between 0.29-0.57g/L could especially better for managing algae.4. Between the body weight of Aristichthys nobilis and biomass of algae, total nitrogen, total phosphorus showed extremely positive correlation. There was the most significant effection on removing algae and total nitrogen, total phosphorus when stocking density was approximately 0.29g/L by ANOVA analysis.5. Compared the removal efficiency on nutrients between these five submerged plants under the same experiment condition, knew that the total nitrogen sequence was Potamogeton malaianus> Hydrilla verticillata> Vallisneria natans> Potamogeton maackianus> Potamogeton crispus, and the total phosphorus was Potamogeton malaianus> Hydrilla verticillata>Potamogeton maackianus> Vallisneria natans> Potamogeton crispus.6. Compared with control group, it was showed that Potamogeton malaianus had the best effect on purifying the water quality and controlling the biomass of algae, Vallisneria natans and Potamogeton maackianus, Potamogeton crispus had taken the second place. Hydrilla verticillata had the significant removal effect on total phosphorus (p=0.000) and phytoplankton (p=0.010), except total nitrogen (p=0.209).更多还原