大型过水性湖泊——洪泽湖浮游植物群落结构及其水质生物评价

摘要

Lake Hongze is an important storage lake for the Eastern route of the South-to-North Water Diversion Project. It plays an important role in climate regulation, flood control and drought protection, tourism and recreation, supply of water resources and aquatic products. In order to understand its phytoplankton community structure and aquatic health status, this study conducted monthly field survey for phytoplankton in Lake Hongze from August 2015 to July 2016. A total of 147 phytoplankton species were identified, belonging to 8 phyla, of which Chlorophyta, Diatomophyta, Cyanophyta were the most abundant. The annual average abundance of phytoplankton was 5.35×107±4.67×107 cells/L, and the average biomass was 14.24±8.52 mg/L. There was obvious spatial and temporal difference in the distribution of phytoplankton in Lake Hongze. In terms of spatial pattern, phytoplankton in Lake Chengzihu had the highest cell abundance, dominated by Chlorophyta; the Lihewa Lake had the second highest abundance and dominated by the Cyanophyta; the centre and south lake region had low phytoplankton abundance, and Chlorophyta or Cyanophyta was dominant in the most sites. In terms of seasonal pattern, phytoplankton were abundant in summer with Cyanophyta dominant. In winter, phytoplankton abundance was low and diatoms were dominant. Compared with the survey in the 1980 s, the number of phytoplankton species (genera) had declined in recent years, and the richness, evenness, etc. had also been lower than those of earlier investigations. The results of bioassessment of phytoplankton showed that Lake Hongze was suffered β-mesosaprobic zone pollution, and its eutrophication level was lower than that of Lake Luoma, but higher than Huaihe River and Lake Gaoyou.%大型过水性湖泊——洪泽湖是南水北调东线工程重要的调蓄湖泊, 在气候调节、防洪抗旱、旅游休闲、水资源和水产品供应等方面都有着重要的作用.为了解其浮游植物群落结构和水体健康状态, 于2015年8月-2016年7月, 对洪泽湖浮游植物进行了逐月野外采样.共鉴定浮游植物147种, 隶属于8门, 其中绿藻门、硅藻门、蓝藻门物种最多.浮游植物细胞丰度全湖年平均值为5.35×107±4.67×107cells/L, 生物量平均值为14.24±8.52 mg/L.洪泽湖浮游植物分布存在明显的时空差异, 空间格局上, 北部成子湖区浮游植物细胞丰度最高, 绿藻门为优势门类;西部溧河洼湖区丰度次高, 蓝藻门为优势门类;湖心区及南部丰度较低, 大部分点位蓝藻门或绿藻门为优势门类.季节动态上, 夏季浮游植物细胞丰度高, 蓝藻门是主要的优势门类;冬季细胞丰度较低, 硅藻门是主要的优势门类.与1980s的调查相比, 近年来浮游植物种 (属) 数有所下降, 丰富度、均匀度等也低于早期调查结果.利用浮游植物进行水质生物评价的结果显示, 洪泽湖总体上处于β-中污带, 与周边水体相比, 洪泽湖富营养化水平低于骆马湖, 但高于淮河、高邮湖.