鄱阳湖浮游植物时空变化特征及影响因素分析

在5月、9月、11月对鄱阳湖浮游植物开展野外调查,分析鄱阳湖浮游植物的时空分布特征及原因.结果表明:在群落结构上,鄱阳湖浮游植物样品中共发现8门107属,其中绿藻门54属,占浮游植物总数的50%.3次调查平均生物量最高的为硅藻门(蓝藻门藻细胞密度最高),生物量为0.29 mg·L-1,占浮游植物总生物量的28%,是鄱阳湖的优势藻门;其次分别为隐藻门、甲藻门和绿藻门,分别占26%、21%和17%.空间分布上,南部湖区浮游植物生物量最高,中部区次之,北部湖口水道区最低;时间分布上,5月份浮游植物生物量最高,11月份最低.温度、悬浮物和透明度是影响藻类时空分布的主要影响因素.鄱阳湖总体水动力较好,水华暴发总体风险小,但中部和南部水动力弱的湖区,藻量高,仍有水华风险.

The characteristics of spatial and temporal variations of phytoplankton in poyang Lake and their influencing factors

The spatial and temporal variations of phytoplankton in Poyang Lake were studied by analyzing water samples collected at May, September and November in 2012. The results showed that the phytoplankton community belonged to 8 phyla and 107genera, of which 54 genera were Chlorophyta accounting for 50% of the total population. Cyanophyta had the highest algae density in three investigations. Bacillariophyceae dominated in phytoplankton with a mean biomass of 28% at a concentration of 0.29 mg · L^-1, followed by Cryptophyta (26%), Pyrrophyta (21%) and Chlorophyta (17%). For the spatial distribution, the order of algae biomass was samples got in the southern area, the central area and the northern area. For the temporal distribution, the highest and lowest biomass were found at May and November, respectively. Temperature, suspended solids and transparency were the main factors affecting the temporal and spatial distribution of the phytoplankton. The risk of algae bloom was low in the whole lake due to the preferable dynamic water stability. However, the risk of algae bloom still existed at the central and southern area because of the weak water dynamic condition.