模拟双水源混合水体附着藻群落结构演替特征

Structural Succession Characteristics of Attached Algae Communities under Dual Water Source Mixing Conditions

摘要: 为探究调水背景下北方水库附着藻的建群规律及其与水环境因子的关系，以南水北调中线天津段重要调蓄水库——尔王庄水库为对象，开展室内模拟混水试验。室内混水试验依据引江水和引滦水设置5个混水比例，2个水深梯度(距表层10 cm和60 cm)开展研究。结果表明：室内模拟混水中附着藻隶属于4门29科42属66种，其中绿藻门种数占比最高，为45.45%；蓝藻门为27.27%，硅藻门为25.76%；金藻门仅1种。蓝藻门优势种数量最多(7种)，湖生假鱼腥藻、长孢藻、游丝藻等在整个试验周期内均持续作为优势种出现。混水比例对不同藻门的影响存在明显差异。统计分析表明，硅藻门生物量受混水比例影响极显著(P < 0.001)，其中A2组显著高于A1、A3和A5，说明A2的水源比例更有利于硅藻积累。混水比例对附着藻多样性的影响主要体现在物种丰富度层面，且表层水层对比例变化更敏感。不同混水比例对附着藻群落的影响主要体现在物种丰富度和综合多样性水平，而对群落均匀度的影响相对较弱。在10 cm水层，不同混水比例对Shannon-Wiener指数和Margalef指数均具有显著影响(P < 0.01)，在60 cm水层，Margalef丰富度指数仍表现出显著差异(P < 0.01)。冗余分析(RDA)表明，本研究所测定的环境因子仅能解释小部分附着藻群落结构的变异，群落大部分变异尚未得到解释。其中，pH是解释群落结构变异最重要的因子，单因子贡献率为77.1%，差异检验达到显著水平(P < 0.01)。本研究阐明了不同混水比例、水深梯度、时间动态下附着藻的群落结构，为混合水体水库的附着藻生长管理及水质生态调控提供科学依据和理论支持。

Abstract: To investigate the community colonization patterns of attached algae in northern reservoirs under water diversion conditions and their relationships with aquatic environmental factors, an indoor simulated water-mixing experiment was conducted using Erwangzhuang Reservoir, an important regulation reservoir in the Tianjin section of the Middle Route of the South-to-North Water Diversion Project. The experiment included five mixing ratios of water from the Yangtze River and Luan River, and two water depth gradients (10 cm and 60 cm below the surface). The results showed that attached algae in the simulated mixtures belonged to 66 species, 42 genera, 29 families, and 4 phyla. Chlorophyta accounted for the highest proportion (45.45%), followed by Cyanophyta (27.27%) and Bacillariophyta (25.76%), while only one species was found in Chrysophyta. Cyanophyta had the most dominant species (7), and Pseudanabaena mucicola, Dolichospermum sp., and Planctonema sp. remained dominant throughout the test period. The effects of water-mixing ratios on different phyla varied significantly. Biomass of Bacillariophyta was extremely significantly affected by mixing ratios (P < 0.001), with Group A2 significantly higher than A1, A3, and A5, indicating that A2 was more favorable for diatom accumulation. Mixing ratios mainly affected species richness, and the surface layer was more sensitive to ratio changes, with weak effects on community evenness. At 10 cm, both Shannon-Wiener and Margalef indices differed significantly (P < 0.01); at 60 cm, only Margalef richness index differed significantly (P < 0.01). Redundancy analysis further indicated that pH was the most critical explanatory factor, with a single-factor contribution rate of 77.1% (P < 0.01). This study clarifies the community structure of attached algae under different mixing ratios, water depths and temporal dynamics, providing scientific basis and theoretical support for attached algae management and water quality ecological regulation in multi-water source reservoirs.