江苏滆湖北部区整治后浮游植物时空分布及环境因子变化规律

Spatio-temporal distribution of phytoplankton and environmental factors in the north part of Lake Gehu( Jiangsu) after muti-treatment

滆湖是我国长江中下游典型的浅水型湖泊,为了解其治理后浮游植物群落时空分布规律,2013年1 12月对其北部区浮游植物及环境因子进行调查.调查期间共检出浮游植物7门43属61种,春、冬季以栅藻（Scenedesmus）和小环藻（Cyclotella）为主要优势种属,夏、秋季以微囊藻（Microcystis）和颗粒直链藻（Melosira granulata）为主要优势种属,采样期间浮游植物生物量最高值为90.6 mg/L,出现在8月份,铜绿微囊藻（Microcystis aeruginosa）占绝对优势.浮游植物平均密度呈现由西向东递减的趋势,植被覆盖区低于敞水区.环境因子分析表明：总氮浓度、总磷浓度、水温是影响滆湖北部区浮游植物密度和生物量的主要因子.比较相同月份湖区内部菱角芦苇区和未治理的敞水区的平均生物量,菱角区生物量较敞水区低约72.7%~91.1%,芦苇区生物量较敞水区低约63.9%~83.7%.在8、9月湖区内敞水区暴发水华时菱角区浮游植物生物量仅为敞水区的14.6%,芦苇区为敞水区的30.3%.

Lake Gehu is a representative shallow lake located in the downstream of Yangtze River in China. To identify the phytoplankton community distribution after its treatment,a survey was conducted on the phytoplanktonic community and environmental factors in its north part from January to December in 2013. According to the survey,there were altogether seven phylum,fourtythree genus and sixty-one species of phytoplankton,mainly with Scenedesmus and Cyclotella in spring and winter,Microcystis and Melosira granulata in summer and autumn. The maximum phytoplankton biomass during sampling period was 90. 6 mg / L in August,mainly with Microcystis aeruginosa. The average density of phytoplankton showed a decreasing trend from west to east,with lower vegetation coverage in the open water area. The environmental factor analysis indicated that total nitrogen,total phosphorus and water temperature were key factors that influence the phytoplanktonic density and biomass in this area. Comparing with the average biomass in the water chestnut area and reed area with that in the untreated open water area in the same month,we found that the water chestnut area decreased with the range of 72. 7%-91. 1%,and 63. 9%-83. 7% in the reed area. In August and September when algal bloom occurred in the open water area,the biomass in the chestnut area and in the reed area was only 14. 6% and30. 3% of that in the water area,respectively.