College of Environmental Science and Engineering, Hohai University, Nanjing 210098, China.
J Environ Sci (China). 2010;22(1):32-9. doi: 10.1016/s1001-0742(09)60071-1.
Increasing levels of pollution within water bodies can cause eutrophication and an associated rapid growth in and reproduction of phytoplankton. Although most frequently occurring in bodies of water such as lakes and dams, in recent years an increasing number of river systems in China have suffered serious algal blooms. The community structure of phytoplankton may differ, however, dependent on the hydrodynamic conditions and nutrient levels within the water body. The field investigation results obtained from a stagnant river in Suzhou City and Taihu Lake, China, showed that in water with higher concentrations of nitrogen and phosphorus, Chlorophyta became the predominant species and in water with lower concentrations of nitrogen and phosphorus, Cyanobacteria became the predominant species. Growth experiments with competitive species, Microcystis aeruginosa Kütz and Scenedesmus quadricauda (Turp.), were conducted at three different nutrient levels. The biomass of algae in pure and mixed cultures was measured under conditions of different N/P ratios at oligotrophic, eutrophic and hypertrophic nutrient levels. The results indicated that the most suitable state for the growth and reproduction of M. aeruginosa and S. quadricauda were eutrophic conditions in both pure and mixed cultures. Under competition, however, the lower medium nutrient levels favoured M. aeruginosa, while the higher medium nutrient levels better suited S. quadricauda. Under similar hydrodynamic conditions, the community structure of phytoplankton in the water body was determined by the dominant species in competition for nutrients.
水体中污染物水平的增加会导致富营养化，并伴随着浮游植物的快速生长和繁殖。尽管这种现象在湖泊和水坝等水体中最为常见，但近年来，中国越来越多的河流系统也遭受了严重的藻类大量繁殖。然而，浮游植物的群落结构可能会因水体中的水动力条件和营养水平而异。从中国苏州市的一条死水河流和太湖进行的实地调查结果表明，在氮磷浓度较高的水中，绿藻成为优势物种，而在氮磷浓度较低的水中，蓝藻成为优势物种。在三种不同的营养水平下，对竞争物种铜绿微囊藻和四尾栅藻进行了生长实验。在贫营养、富营养和过营养营养水平下，在不同的 N/P 比条件下测量了纯培养和混合培养中藻类的生物量。结果表明，在纯培养和混合培养中，铜绿微囊藻和四尾栅藻生长和繁殖的最适状态是富营养条件。然而，在竞争条件下，较低的培养基营养水平有利于铜绿微囊藻，而较高的培养基营养水平更适合四尾栅藻。在相似的水动力条件下，水体中浮游植物的群落结构由竞争养分的优势物种决定。
