LD水库浮游植物群落结构特征及水质评价

Characteristics of phytoplankton community structure and water quality assessment in LD Reservoir

浮游植物具有生命周期短、对环境变化敏感等特点,其群落结构能较好地反映水生生态系统的营养状况,被作为评价水体营养水平的重要环境指示生物。为探究LD水库浮游植物群落结构特征及水质健康状况,于2021年5—12月对水库4个位点进行4次采样,对其水质指标和浮游植物群落结构进行分析,采用单因素方差分析方法进行数据分析。结果表明,水库水质整体为Ⅱ类水,营养水平为轻度富营养状态;共检测出藻类6门30属37种,季节演替变化为绿藻门—绿藻门—裸藻门—硅藻门。水库浮游植物平均细胞密度为(4.24×10^(6)±2.69×10^(6))cells/L,春夏两季细胞密度明显高于秋冬两季。生物量密度平均值(10.53±6.71)mg/L,最高值出现于春季,最低值出现于秋季,且季节间生物量密度差异无统计学意义(P>0.05)。总氮平均浓度为(1.444±0.590)mg/L,总磷平均浓度为(0.004 5±0.004 0)mg/L,pH值年平均为8.25±1.32,水体总体呈弱碱性,叶绿素a平均浓度为(18.59±15.14)μg/L,溶氧量年平均值为8.69±0.60;春夏秋冬的总氮和pH差异有统计学意义(P<0.05),而叶绿素a、总磷差异无统计学意义(P>0.05)。RDA分析表明,影响水库浮游植物群落状况的环境指标主要为硝酸盐氮。

Phytoplankton has the characteristics of short life cycle and sensitivity to environmental changes,and its community structure can better reflect the nutritional status of aquatic ecosystems,and has become an important environmental indicator for evaluating the nutritional level of water bodies.To explore the structural characteristics of phytoplankton communities in the LD Reservoir and evaluate its water quality,four samples were taken from four sites in the reservoir from May to December 2021,and the water quality index and phytoplankton community structure were analyzed,and the data was analyzed using one-way ANOVA.The results indicated that the water quality of Liudu Reservoir was classified as Class II water,with a slightly eutrophic level.A total of 6 phyla,30 genera,and 37 species of algae were detected in the Liudu Reservoir,with seasonal succession changing from Chlorophyta,Chlorophyta,Euglenophyta and Diatoma.The average cell density of phytoplankton in the reservoir was measured to be(4.24×10^(6)±2.69×10^(6))cells/L,the cell density in spring and summer was significantly higher than that in autumn and winter.The average biomass density was measured to be(10.53±6.71)mg/L,the biomass density value was highest in spring and lowest in autumn.There was no significant difference in biomass density between seasons(P>0.05).The overall average concentration of total nitrogen was measured to be(1.444±0.590)mg/L,and the overall average concentration of total phosphorus was measured to be(0.0045±0.0040)mg/L.The annual average pH was measured to be 8.25±1.32,and the water was weakly alkaline.The overall average concentration of chlorophyll a was measured to be(18.59±15.14)μg/L.The annual average dissolved oxygen content was measured to be(8.69±0.60).And the differences in total nitrogen and pH between spring,summer,autumn,and winter were extremely significant(P<0.05),while there was no significant difference in chlorophyll a and total phosphorus(P>0.05).RDA analysis showed that the important environmental indicators affecting the growth status of phytoplankton communities in the Liudu Reservoir was nitrate nitrogen.