【作者】 王崇；

【导师】 孔海南；

【作者基本信息】 上海交通大学 ， 环境工程， 2010， 博士

【摘要】 通过研究与细胞生长变化同步的细胞色素含量、细胞碳水化合物含量、细胞磷含量和细胞体积等细胞自身特征的变化,建立了基于细胞自身特征的生长速率预测模型；研究了水华发生前浮游植物群落的演替和水体理化性质的变化,以及浮游植物色素的变化情况,结果显示可以用色素指示浮游植物主要藻类群体的变化情况,而浮游植物物种多样性有可能做为蓝藻水华早期预警的群落水平上的因子。首先研究了物理因素光照和化学因素氮、磷营养盐浓度对典型水华蓝藻铜绿微囊藻生长的影响,以及在生长变化过程中细胞色素含量、细胞碳水化合物含量、细胞N含量、细胞P含量和细胞体积等细胞自身特征的变化情况。采用单种分批培养的方式,以常见水华藻种铜绿微囊藻(FACHB 905)为研究对象,试验采用不同的光强和不同的氮或磷营养浓度。结果发现光照与N浓度对铜绿微囊藻的比生长速率、细胞N含量、细胞叶绿素a含量、细胞P含量和细胞碳水化合物含量均有明显影响,它们表现出同步的变化趋势；光照与磷对铜绿微囊藻的比生长速率、细胞叶绿素a含量、细胞P含量、细胞碳水化合物含量和细胞体积均表现出交互作用；研究发现在光照和N或者P交互影响蓝藻生长的过程中,细胞色素含量、细胞碳水化合物含量、细胞N含量、细胞P含量和细胞体积等细胞自身特征也都发生明显的同步变化,这表明,生长与细胞色素色素含量、细胞碳水化合物含量、细胞N含量、细胞P含量和细胞体积等细胞自身特征之间可能存在着相关关系。论文研究了Fe和Cu、Mn、Zn等微量金属营养元素对铜绿微囊藻生长的影响,以及在生长变化过程中细胞色素含量、细胞碳水化合物含量、细胞N含量、细胞P含量和细胞体积等细胞自身特征的变化情况。采用单种分批培养的方式,以常见水华藻种铜绿微囊藻(FACHB 912,从太湖分离)为研究对象,分别通过改变BG-11培养基中柠檬酸铁铵、CuSO4·5H2O、MnCl2·4H2O和ZnSO4·7H2O的加入量来调节Fe3+、Cu2+、Mn2+、Zn2+的浓度。结果发现,在合适的范围内,提高这些元素的浓度可促进细胞生长以及提高细胞色素含量、细胞碳水化合物含量、细胞N含量、细胞P含量和细胞体积,但过高的浓度也会导致对这些特征的抑制作用；最适合铜绿微囊藻生长的Fe、Cu、Mn、Zn浓度分别约为12.3μmol Fe/L、0.079μmol Cu/L、3.57μmol Mn/L、0.386μmol Zn/L,高于这些浓度则出现了不同程度的抑制现象；与蓝藻细胞生长变化同步,细胞色素含量、细胞碳水化合物含量、细胞N含量、细胞P含量和细胞体积等细胞自身特征也都发生明显的同步变化。分批培养条件下铜绿微囊藻的生长呈现明显的4个阶段,即迟缓期、对数生长期、稳定生长期、衰老期。不同生长阶段的比生长速率、细胞分裂率、显微图像周长和面积、圆度、细胞叶绿素a含量等均呈现不同的变化规律,这表明细胞生长的环境条件会影响细胞的生长和自身特征。此外,比生长速率与分裂率、细胞体积、细胞圆度等特征可能存在一定变换关系。本研究发现,蓝藻比生长速率与细胞碳水化合物含量成负相关关系,因此细胞生长较快时其细胞碳水化合物含量较低、有利于上浮,从而容易导致水华的发生；在控制P浓度的条件下,本研究建立了基于细胞P含量、细胞碳水化合物含量和细胞体积的耦合模型来预测比生长速率,可以达到较好的预测效果(Adjusted R2=0.698, P<<0.001)。细胞自身特征是环境因子对细胞综合作用在细胞自身上的直接反映。依据细胞特征预测生长速率可以避免不同水域环境因子差别较大的问题。最后,本研究通过围隔中营养浓度的调控,原位诱发了蓝藻(主要是钝顶节旋藻,Arthrospira platensis)水华。研究了水华发生前浮游植物群落的演替、水体理化性质的变化和色素的变化。研究认为,单纯通过监测水化学参数难以预测蓝藻水华的发生,而前期水体浮游植物的多样性有可能作为预警因子对蓝藻水华的发生进行预警。研究进一步指出了通过测定浮游植物群落色素含量及比例的方法来指示环境中不同微藻群体的演替,从而监测浮游植物群落结构的动态。更多还原

【Abstract】 A combined model was constructed for the prediction of cyanobacterial growth based on the relationship between growth and cell characteristics such as cell pigment content, cell phosphorus content, cell carbohydrate content and cell size. And also, the indicator of diversity index may be considered for the early-warning of cyanobacterial blooms; furthermore, the ratio of characteristic pigment to cholorphyll a was suggested to be used to indicate the variation of the structure of phytoplankton community, which should be useful for studying the dynamics of phytoplankton community.Firstly, the effects of irradiance as a physical factor and ambient nitrogen or phosphorus concentrations as chemical factors on the growth of typically bloom-forming Microcystis aeruginosa (FACHB 905), as well as the simultaneous variations of cell pigment content, cell phosphorus content, cell nitrogen content, cell carbohydrate content and cell size with the variation of growth, were studied. The experiments were carried out by adopting uni-algal batch culture, and the typically bloom-forming Microcystis aeruginosa (FACHB 905) was employed. Different phosphorus or nitrogen concentrations in the medium were set, and a gradient of 6 irradiances was employed. Under N-controlled condition, the specific growth rate, cell nitrogen content, and cell cholorphyll a content were affected by N concentration and irradiance intensity, which showed simultaneous and similar variation. There existed interactive effects of irradiance and phosphorus on the growth rate, cell cholorphyll a content, cell phosphorus content, cell carbohydrate content and cell size. The cell characteristics such as cell pigment content, cell phosphorus content, cell nitrogen content, cell carbohydrate content and cell size showed simultaneous variation with growth rate, which indicated that there may exist some relationship between them.The bloom-forming Microcystis aeruginosa (FACHB 912) that was isolated from Lake Taihu was used for the study of the effect of Fe, Cu, Mn and Zn on the growth of cyanobacteria. The experiments were carried out by adopting uni-algal batch culture, and different concentrations of Fe, Cu, Mn and Zn were employed. It was found that Fe, Cu, Mn and Zn were essential micronutrient for the growth of cyanobacteria, which would promote the growth, as well as the cell size and cell content of pigment, carbohydrate, nitrogen, and phosphorus. However, excess concentration of these metals would be toxic and inhibited the growth. The optimal concentrations for the growth of M. aeruginosa were about 12.3μmol Fe/L、0.079μmol Cu/L、3.57μmol Mn/L、0.386μmol Zn/L, higher than which will be toxic. The cell characteristics such as cell pigment content, cell phosphorus content, cell nitrogen content, cell carbohydrate content and cell size showed simultaneous variation with growth rate, which indicated that there may exist some relationship between them.The growth of M. aeruginosa in batch culture showed four phases as lag phase, exponential phase, steady phase, senescence phase. The specific growth rate, division ratio, the microscopic photo perimeter and area of the cell, cell roundness, cell cholorophyll a content showed different variation patterns in the four growth phases, which indicated that the surrounding conditions could impact the growth and cell characteristics. On the other hand, the variation of specific growth rate was in relation to that of cell characteristics such as division ratio, cell size, cell roundness, etc.Based on the variations of growth rate and cell carbohydrate content, it was found that the specific growth rate was inversely proportional to cell carbohydrate content. The growth rate was relatively high when the cell carbohydrate content was low. It can be indicated that high growth occurs when cells are buoyant, which favors blooms. Under P controlled condition, a combined model was constructed for the prediction of cyanobacterial growth, and a better prediction was achieved by the combined model (Adjusted R2=0.698, P<<0.001) than the prediction model using any one factor of cell pigment content, cell phosphorus content, cell carbohydrate content or cell size. Cell characteristics are the reflection of the combined effect of environmental parameters on cells. It will be suitable to be applied in various environments to predict the growth.Finally, a cyanobacterial(Arthrospira platensis) bloom was induced in situ by nutrient manipulation in an enclosure. The succession of the phytoplankton community and the water chemistry variations before the appearance of bloom, as well as their relationship, were investigated. The cell pigment variations were studied simultaneously. The Pearson’s correlation analysis showed that there was no significant correlation between water chemistry and green algal or cyanobacterial composition, indicating that water chemistry variations were not suitable to be used as indicators for cyanobacterial-bloom early-warning. However, the diversity index of the phytoplankton community decreased sharply before the bloom appeared. Therefore, the diversity index of phytoplankton community may be considered as an indicator for cyanobacterial-bloom early-warning. In addition, the cell pigment variations represented the changes of community structure, which should be useful for studying the dynamics of phytoplankton community.更多还原