水体氮磷浓度对两种沉水植物上附着藻类的影响

为了了解富营养化进程中湖泊水体氮、磷浓度升高对不同沉水植物上附着藻类的影响,通过室内模拟实验,设置3组不同氮磷浓度,研究了常见的沉水植物苦草(Vallisneria natans(Lour.)Hara)和狐尾藻(Myriophyllum spicatum L.)上附着藻类生物量及其种群组成.结果表明,附着藻类生物量随水体氮、磷浓度的升高呈显著增加的趋势;狐尾藻上附着藻类生物量均高于苦草,且随富营养化水体氮、磷浓度升高差距越来越大.不同沉水植物上藻类群落组成均以硅藻门、蓝藻门及绿藻门占优势,但优势藻组成和优势藻数量存在差异.研究结果不仅丰富了淡水水体附着藻类生态学的理论知识,也可为富营养化湖泊生态修复过程中沉水植物群落的构建提供一定的理论依据.

Effects of nitrogen and phosphorus concentration on epiphytic algae living on two types of submerged plants

In order to study the effects of nutrient concentration on the biomass and community of epiphytic algae living on Vallisneria natans(Lour.) Hara and Myriophyllum spicatum L. in eutrophic water, a laboratory simulation experiment based on completely randomized design with three replicates was conducted, under three levels of nitrogen and phosphorus concentration in the water phase (N-P:2.5, 0.25 mg·L^-1; 4.5, 0.45 mg·L^-1; 12.5, 1.25 mg·L^-1). The results show that with the increase of nitrogen and phosphorus concentration, the biomass of epiphytic algae increased, and the biomass of epiphytic algae living on Vallisneria natans was higher than that living on Myriophyllum spicatum. The difference in epiphytic algal biomass between Vallisneria natans and Myriophyllum spicatum became greater with the increase of nitrogen and phosphorus concentration. The community of epiphytic algae living on the two types of submerged plants were dominated by Bacillariophyta, Cyanophyta and Chlorophyta, while there was a difference in population of dominant species. The results of this study not only broad the knowledge of the algal ecology, but also provide a theoretical basis for selecting macrophytes suitable for ecological restoration in eutrophic lakes.