禁渔初期长江上游保护区浮游植物群落结构及水生态健康评价*

The Community Structure of Planktonic Plants and Water Ecological Health Assessment in the Upper Yangtze River Protection Area during the Early Period of Fishing closed season

关键词:  浮游植物、群落结构、生物完整性指数

Key words:  phytoplankton, community  structure, biological  integrity index

摘要:

为研究长江上游保护区浮游植物群落结构及水生态健康状况,本研究分别于2023年1月(枯水期)、6月(丰水期)进行生物学调查。共鉴定出浮游植物7门53属92种(含变种),其中硅藻门种类最多,18属48种,其次为绿藻门,群落结构为硅藻-绿藻-蓝藻型,优势种以硅藻门种类为主且优势度较大。各断面浮游植物平均密度在6.45×104^-1.29×105 ^cells/L之间,平均值为8.76×104 ^cells/L,平均生物量在0.013-0.372 mg/L之间,平均值为0.135 mg/L。利用浮游植物分析数据,筛选出物种多样性指数、物种丰富度指数、非硅藻属类单元数、硅藻商、藻类总生物量、蓝藻门生物量构建生物完整性指数(P-IBI),评价长江上游保护区水生态健康,结果显示调查水域处于“健康-亚健康”状态,枯水期河流健康状态表现好于丰水期。

Abstract:

In order to study the structure of phytoplankton communities and the health status of aquatic ecosystems in the protected areas of the upper reaches of the Yangtze River, biological surveys were conducted in January 2023 (dry season) and June 2023 (wet season). A total of 92 species (including varieties) of phytoplankton were identified, belonging to 53 genera and 7 phyla. Among them, the Bacillariophyta phylum had the largest number of species, with 48 species from 18 genera, followed by Chlorophyta phylum, exhibiting a Bacillariophyta-Chlorophyta- Cyanophyta pattern. The density of phytoplankton at each cross-section ranged from 6.45×10⁴ cells/L to 1.29×10⁵ cells/L, with an average of 8.76×10⁴ cells/L. The average biomass ranged from 0.013 mg/L to 0.372 mg/L, with an average value of 0.135 mg/L. Using the analysis data of plankton, we selected the species diversity index, species richness index, the number of non-diatom genera, diatom quotient, total biomass of algae, and cyanobacteria biomass to construct the biological integrity index (P-IBI). We then evaluated the aquatic ecological health of the upstream protection zone of the Yangtze River. The results showed that the surveyed waters were in a "healthy to sub-healthy" state, and the river health status was better in the dry season than in the wet season.