金鱼藻附生生物初级生产力的研究

Research on Primary Productivity of Ceratophyllum demersum Epiphytic Organisms

采用现场调查与模拟实验相结合的方法。白洋淀夏季优势沉水植物金鱼藻附生藻类的群落结构、现存量和光合作用速率,分析了附生生物对金鱼藻光合速率的影响,探讨了附生生物在湖泊草型生态系统和藻型生态系统相互转化过程中的作用。结果表明,白洋淀不同水域的营养盐浓度差异较大。东关码头区域营养盐较高水质较差,总氮(TN 6.02 mg/L)和总磷(TP 0.94 mg/L)均异常偏高;采蒲台水域营养盐水平较低水质较好,氮磷(TN 2.08 mg/L,TP 0.06 mg/L)的含量均较低;鸳鸯岛、寨南、圈头3个样点水体营养盐浓度介于东关码头与采蒲台之间。水质状况与附着藻类密度、多样性及对金鱼藻的光合抑制率密切相关,营养盐浓度低的采蒲台样点附着在金鱼藻上的藻类密度为134.5×104ind/L,经鉴定优势种为月形短缝藻(Eunotia lunaris):附着藻类的多样性指数为0.53,对其金鱼藻光合作用的抑制率仅为20.0%。而营养盐浓度高的东关码头水域附着藻类密度为375.7×104ind/L,多样性指数为0.52,通过镜检该样点附着藻类的优势种同为月形短缝藻,其对金鱼藻的光合抑制达到79.1%。研究发现在营养盐高的水域附着藻类对金鱼藻相对营养盐低的水域抑制率较高,附着藻类的多样性也相对较大。说明营养盐的高低对附着藻类的密度、多样性及其对金鱼藻的光合抑制率有密切联系。

Field visit and simulation experiment were done to measure the community structure, the existing volume and the rate of photosynthesis of Ceratophyllum demersurn epiphytic algae under different nutritional conditions, which is an advantageous submerged plant in Baiyangdian in summer. The influence of epiphytic organisms on Ceratophyllum demersum photosynthetic rate was analyzed and the role of epiphytic organisms in the process of mutual transformation of lakes＇ grasstype ecosystems and algae-based ecosystems was explored. As shown in the result, nutrient concentrations in different waters of Baiyangdian are quite different. In Dongguan Pier area, the nutrient is higher and the water quality is poorer, both total nitrogen （TN 6.02 mg/L） and total phosphorus （TP 0.94 rag/L） are abnormally high. In Caiputai water, the nutrient level is ＇ lower and the water quality is better, the contents of nitrogen and phosphorus （TN 2.08 mg/L, TP 0.06 mg/L） are all lower. In the sample waters of Mandarin Duck Island, Zhainan and Quantou, the nutrient concentration is between Dongguan Pier area and Caiputai waters. The water quality is closely related to the density and diversity of epiphytic algae, and photosynthetic inhibition rate of epiphytic algae towards Ceratophyllum demersum. In Caiputai water, the nutrient concentration is relatively low and the epiphytic algae density of Ceratophyllum demersum is 134.5×10^4 ind/L. As identified, the advantageous species is Eunotia lunaris, with the diversity index of epiphytic algae as 0.53, whose inhibition rate towards the photosynthesis of Ceratophyllum demersum is only 20.0%. However, in Dongguan Pier area, the nutrient concentration is high, with the epiphytic algae density as 375.7×10^4 ind/L and the diversity index as 0.52. Through the microscopy, the advantageous species of epiphytic algae of this sample is also Eunotia lunaris, whose inhibition rate towards the photosynthesis of Ceratophyllum demersum reaches 79.1%. It was found that concentrations of nutrients are closely related to the density, diversity of epiphytic algae and photosynthetic inhibition rate of Ceratophyllum demersum.