三峡库区甘井河水域牧场浮游植物群落结构及水质评价

为了解三峡库区的忠县甘井河段水域牧场生态渔业对水环境的影响, 于2013 年3、6、9 及12 月按季度对该河段4 个站点进行了浮游植物群落结构及水体理化因子的监测, 并采用生物多样性指数法和综合营养状态指数法对水体营养状况进行了评价。结果表明, 该河段浮游植物有7 门93 个属种, 其中绿藻门的物种数最多, 有37 种, 占浮游植物群落总数的39.79%, 其次为硅藻门和蓝藻门, 物种数分别为26 种和13 种,分别占浮游植物群落总数的27.96%和13.98%;浮游植物的年均丰度为757.67104 ind./L, 变化范围(3.065743.99)104 ind./L, 年均生物量为4.40 mg/L, 变化范围0.0317.67 mg/L;水体的年平均透明度为1.18 m, 叶绿素a、总磷、总氮含量分别为8.54 g/L、0.13 mg/L、1.95 mg/L;浮游植物香农多样性指数(H')、均匀度指数(J)年均值分别为2.90 和0.88, 全年综合营养状态指数值为37.5971.86, 由此推断, 甘井河水质属于中污染轻污染状态、中营养型富营养型。在鱼类生长旺季的6 月, 甘井河段养殖区内的水质优于非养殖区, 这可能与养殖区内放养滤食性鱼类有关, 证实了水域牧场没有带来水环境的污染, 反而能提高生物多样性, 在一定程度上改善了水体。  

THE STUDY OF THE COMMUNITY STRUCTURE OF THE PHYTOPLANKTON AND THE ASSESSMENT OF THE WATER QUALITY IN THE GANJING RIVER OF THE THREE GORGE RESERVOIR

In order to reveal the impact of aqua farms on the water environment in the Ganjing River of the Three-Gorge Reservoir, we investigated the community structure of the phytoplankton and tested the physyco-chemical parameters of the water at four sampling sites in the Ganjing River in different seasons. We applied regular methods and collected water samples in March, June, September and December of 2013. We observed 93 phytoplankton species that belonged to seven phyla. The dominant phylum was Chlorophyta (37 species), followed by Bacillariophyta (26 species) and Cyanophyta (13 species), and these three phyla accounted for 39.79%, 27.96% and 13.98% of the entire sample. The average annual abundance of the phytoplankton was 7.58106 cells/L, ranging from 3.06 to 5743.99104 cells/L. The average annual biomass was 4.40 mg/L, ranging from 0.03 to 17.67 mg/L. The average annual Secchi-depth (SD), chlorophyll-a, total phosphorus (TP) and total nitrogen (TN) were 1.18 m, 8.54 g/L, 0.127 mg/L and 1.95 mg/L respectively. The mean Shannon-Weiner diversity index was 2.90, ranging from 1.11 to 4.17. The average annual Pielou evenness index was 0.88, ranging from 0.34 to 1.49. The comprehensive trophic level index of the Ganjing River was between 37.59 and 71.86 with an average of 56.71. The water quality of the Ganjing River was evaluated to be eutrophic and mesotrophic. The water quality of the aquaculture area was better than the other areas in June when fishes grew rapidly, and in other months, there was no obvious difference in the water quality between the aquaculture area and the other areas. This suggested that the filter-feeding fishes might moderately improve the biodiversity and the water quality.