Zhao Lu, Ouyang Tian, Ji Lu-Lu, Yang Song-Qi, Zheng Bao-Hai, Du Yu-Xin, Li Yu-Xin, Li Jia-Xin, Shi Jun-Qiong, Wu Zhong-Xing
Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Key Laboratory of Plant Ecology and Resources in Three Gorges Reservoir Region, Southwest University, Chongqing 400715, China.
Huan Jing Ke Xue. 2023 Feb 8;44(2):857-867. doi: 10.13227/j.hjkx.202203240.
In order to investigate the relationship between phytoplankton community functional group compositions and resource use efficiency in important tributaries of the Three Gorges Reservoir, phytoplankton and environment parameters were sampled from five tributaries, the Xiangxi River, Daning River, Meixi River, Pengxi River, and Huangjin River, in August and November, 2020. There were 119 species (variants) belonging to 62 genera and 7 phyla identified in summer, whereas 118 species (variants) belonging to 7 divisions of 58 genera were found in winter. According to Padisak's theory, all phytoplankton were divided into 25 functional groups, of which there were six important functional groups in both summer and winter:L0, H1, D, Y, MP, and P in summer and L0, H1, A, M, MP, and Y in winter. The -diversity of the phytoplankton functional group in summer was higher than that in winter. Moreover, a higher -diversity was also found in downstream samples relative to that in upstream samples, indicating that the community structure was more complex, and the community stability was relatively better in downstream regions of the rivers. Redundancy analysis (RDA) showed that the environment factors, i.e., , pH, permanganate index, WT, and RUE, significantly affected phytoplankton functional groups (<0.05). Variance partitioning analysis (VPA) indicated that environmental factors had a higher explanatory degree for the change in functional group composition in summer (45.23%); on the contrary, resource use efficiency had a higher explanatory degree in winter (42.33%). The linear fitted model showed that functional groups L0, H1, D, and Y showed a significant positive correlation relationship with RUE and RUE in summer, whereas only four functional groups (M, MP, Y, and A) had a linear relationship with RUE, and all function groups had a good linear relationship with RUE in winter. These results indicated that the functional groups belonging to cyanobacteria, dinoflagellates, and cryptophyta were more efficient at using limited resources in summer, whereas the diatoms had a good linear relationship with resource use efficiency and formed a dominant group in the low temperature environment of winter. These results suggest that the impounding of the Three Gorges Reservoir area can significantly change the resource use efficiency of phytoplankton, resulting in changes in the phytoplankton functional group composition and community structure.
为了研究三峡水库重要支流浮游植物群落功能群组成与资源利用效率之间的关系，于2020年8月和11月从香溪河、大宁河、梅溪河、蓬溪河和黄金河这五条支流采集了浮游植物和环境参数样本。夏季共鉴定出7门62属119种（变种），冬季共发现58属7个门类的118种（变种）。根据帕迪萨克的理论，所有浮游植物被分为25个功能群，其中夏季和冬季均有六个重要功能群：夏季为L0、H1、D、Y、MP和P，冬季为L0、H1、A、M、MP和Y。夏季浮游植物功能群的α多样性高于冬季。此外，下游样本的α多样性也高于上游样本，这表明河流下游区域的群落结构更复杂，群落稳定性相对更好。冗余分析（RDA）表明，环境因子，即溶解氧、pH值、高锰酸盐指数、水温（WT）和资源利用效率（RUE），对浮游植物功能群有显著影响（P<0.05）。方差分解分析（VPA）表明，环境因子对夏季功能群组成变化的解释度更高（45.23%）；相反，资源利用效率在冬季的解释度更高（42.33%）。线性拟合模型表明，夏季功能群L0、H1、D和Y与资源利用效率（RUE）呈显著正相关，而冬季只有四个功能群（M、MP、Y和A）与资源利用效率呈线性关系，所有功能群与资源利用效率均具有良好的线性关系。这些结果表明，属于蓝藻、甲藻和隐藻的功能群在夏季对有限资源的利用效率更高，而硅藻与资源利用效率呈良好的线性关系，并在冬季低温环境中形成优势类群。这些结果表明，三峡库区蓄水可显著改变浮游植物的资源利用效率，导致浮游植物功能群组成和群落结构发生变化。
