Fang Lingchao, Mi Wujuan, Li Yuan, Ai Xiaohan, Bi Yonghong
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
J Environ Sci (China). 2025 Nov;157:111-122. doi: 10.1016/j.jes.2025.01.004. Epub 2025 Jan 11.
Water level fluctuations (WLFs) constituted a dominant factor controlling the structure and function of freshwater ecosystems but the mechanism of WLFs on phytoplankton community structure was still unknown. We investigated the characteristics of phytoplankton community structure in Xiangxi Bay from January 2017 to December 2020. Results indicated water level (WL) of the Three Gorges Reservoir was divided into four distinct stages: the decreasing stage (DS), the low water level stage (LS), the storage stage (SS), and the high water level stage (HS). Notably, Cyanophyta predominated during the LS, with Microcystis sp. being the dominant species. Bacillariophyta was predominant in other three WL stages, with Melosira sp. and Cyclotella sp. as the dominant species. The highest biomass appeared in LS, whereas the lowest appeared in HS. Moreover, alpha diversity appeared to be lower in both HS and LS compared to DS and SS. Redundancy analysis showed WL as the key driver of phytoplankton community. Partial least squares path model analyses demonstrated that WL not only altered chemical factors (path coefficient = -0.62, P < 0.01), thereby leading to changes in phytoplankton biomass (path coefficient = 0.56, P < 0.01), but also changed the physical factors (path coefficient = -0.69, P < 0.01) and consequently had an impact on phytoplankton biomass (path coefficient = 0.33, P < 0.01). Furthermore, WL influenced phytoplankton diversity by altering chemical and physical factors. In conclusion, WL was an important factor influencing phytoplankton community, which implied that reservoir operation was the potential strategy to regulate phytoplankton communities.
水位波动是控制淡水生态系统结构和功能的主要因素，但水位波动对浮游植物群落结构的影响机制尚不清楚。我们调查了2017年1月至2020年12月香溪河库湾浮游植物群落结构特征。结果表明，三峡水库水位分为四个不同阶段：下降期（DS）、低水位期（LS）、蓄水期（SS）和高水位期（HS）。值得注意的是，在低水位期蓝藻占优势，微囊藻属为优势种。硅藻在其他三个水位阶段占优势，优势种为直链藻属和小环藻属。生物量最高出现在低水位期，最低出现在高水位期。此外，与下降期和蓄水期相比，高水位期和低水位期的α多样性似乎较低。冗余分析表明水位是浮游植物群落的关键驱动因素。偏最小二乘路径模型分析表明，水位不仅改变化学因子（路径系数=-0.62，P<0.01），从而导致浮游植物生物量变化（路径系数=0.56，P<0.01），还改变物理因子（路径系数=-0.69，P<0.01），进而对浮游植物生物量产生影响（路径系数=0.33，P<0.01）。此外，水位通过改变化学和物理因子影响浮游植物多样性。总之，水位是影响浮游植物群落的重要因素，这意味着水库调度是调节浮游植物群落的潜在策略。
