Key Laboratory for Conserving Wildlife with Small Populations in Yunnan, Southwest Forestry University, Kunming, Yunnan, China.
Southwest Survey and Planning Institute of National Forestry and Grassland Administration, Kunming, Yunnan, China.
PeerJ. 2024 Sep 13;12:e17972. doi: 10.7717/peerj.17972. eCollection 2024.
The Xiao Jiang River, as a crucial element of ecological restoration in the upper reaches of the Yangtze River, plays an indispensable role in agricultural water utilization and water ecology within its watersheds. The water quality status of the Xiao Jiang River not only impacts local water-ecological equilibrium and economic benefits but also holds paramount importance for sustaining ecosystem health in the Yangtze River basin. Plankton surveys and environmental physicochemical detection were conducted in the major channel region of the Xiao Jiang River in dry and wet periods in 2022 to better understand the diversity of eukaryotic plankton and its community structure characteristics. Environmental DNA is an emerging method that combines traditional ecology with second-generation sequencing technology. It can detect species from a single sample that are difficult to find by traditional microscopy, making the results of plankton diversity studies more comprehensive. For the first time, environmental DNA was used to investigate eukaryotic plankton in the Xiao Jiang River . The results showed that a total of 881 species of plankton from 592 genera in 17 phyla were observed. During the dry period, 480 species belonging to 384 genera within17 phyla were detected, while, during the wet period, a total of 805 species belonging to 463 genera within 17 phyla were recorded. The phylum Ciliophora dominated the zooplankton, while the phylum Chlorophyta and Bacillariophyta dominated the phytoplankton. The presence of these dominant species indicate that the water quality conditions in the study area are oligotrophic and mesotrophic. Principal coordinate analysis and difference test showed that the number of plankton ASVs, abundance, species richness, dominating species, and diversity indices differed between the dry and wet periods. Spearman correlation analysis and redundancy analysis (RDA) of relative abundance data with environmental physicochemical factors revealed that water temperature (WT), dissolved oxygen (DO), potential of hydrogenacidity (pH), ammonia nitrogen (NH3-N), total nitrogen (TN), electrical conductivity (EC) and the determination of redox potential (ORP) were the main environmental physicochemical factors impacting the plankton community structure. The results of this study can serve as a provide data reference at the plankton level for water pollution management in the Xiao Jiang River, and they are extremely important for river ecological restoration and biodiversity recovery in the Yangtze River basin.
湘江作为长江上游生态修复的关键要素，在流域内的农业用水和水生态方面发挥着不可或缺的作用。湘江的水质状况不仅影响当地水生态平衡和经济效益，而且对维持长江流域生态系统健康至关重要。为了更好地了解真核浮游生物的多样性及其群落结构特征，于 2022 年在湘江干流枯水期和丰水期进行了浮游生物调查和环境理化检测。环境 DNA 是一种将传统生态学与第二代测序技术相结合的新兴方法，它可以从单个样本中检测到传统显微镜难以发现的物种，使浮游生物多样性研究的结果更加全面。这是首次利用环境 DNA 调查湘江真核浮游生物。结果表明，共观察到 17 门 592 属 881 种浮游生物。在枯水期，共检测到 17 门 384 属 480 种，在丰水期，共记录到 17 门 463 属 805 种。纤毛门是浮游动物的优势类群，绿藻门和硅藻门是浮游植物的优势类群。这些优势物种的存在表明，研究区域的水质条件为贫营养型和中营养型。主坐标分析和差异检验表明，浮游生物 ASVs 数量、丰度、物种丰富度、优势种和多样性指数在干湿两季存在差异。相对丰度数据与环境理化因子的 Spearman 相关性分析和冗余分析（RDA）表明，水温（WT）、溶解氧（DO）、潜在酸度（pH）、氨氮（NH3-N）、总氮（TN）、电导率（EC）和氧化还原电位（ORP）的测定是影响浮游生物群落结构的主要环境理化因素。本研究结果可为湘江水污染管理提供浮游生物水平的数据参考，对长江流域河流生态恢复和生物多样性恢复具有重要意义。
