作者：Tan, Q., Zhang, Q., Zhu, L., Liu, B., Zhang, R., Guo, C., Shan, K., Qin, B. & Shi, W.

Under eutrophication stress, phytoplankton communities typically exhibit reduced diversity and increased homogenization. However, variations in hydrological connectivity can reshape community structure, potentially leading to divergence within the same eutrophic region. We conducted a seasonal survey of phytoplankton communities at 117 sites across rivers, lake, and ponds in the Taihu Lake Basin, a hypereutrophic plain region in China (May 2023-January 2024), and used NMDS, OMI niche analysis, XGBoost, and LMMs models to analyze community composition, diversity, stability, and environmental responses. Results demonstrated that hydrologically connected rivers and Taihu Lake harbored similar Bacillariophyta-Cyanophyta assemblages with low diversity and high spatial stability, whereas isolated ponds were dominated by Euglenophyta and Pyrrophyta with higher diversity, greater seasonal stability, but pronounced spatial heterogeneity. OMI analysis revealed higher niche overlap in ponds (40%) than in Taihu Lake (19%) or rivers (23%), reflecting convergent adaptation to stable environments. Phytoplankton diversity peaked at TN similar to 2.7 mg/L, beyond which Cyanophyta dominance suppressed diversity. Cyanophyta biomass in Taihu Lake and rivers was highly sensitive to air temperature, whereas ponds showed minimal response; under the SSP5-8.5 scenario, Cyanophyta biomass is projected to increase by 0.51 mg/L in Taihu lake and 0.43 mg/L in rivers by 2100. Even under high eutrophication pressure, hydrological connectivity can shape phytoplankton composition and their sensitivity to environmental changes, necessitating water body-specific management strategies in these regions.

在富营养化胁迫下，浮游植物群落通常表现出多样性降低和同质化加剧的趋势。然而，水文连通性的差异可重塑群落结构，甚至导致同一富营养化区域内出现群落分化。我们于2023年5月至2024年1月，在中国重度富营养化的平原区域——太湖流域，对河流、太湖及池塘共117个样点的浮游植物群落开展了季节性调查，并运用非度量多维尺度分析（NMDS）、离均指数（OMI）生态位分析、极端梯度提升（XGBoost）和线性混合模型（LMMs），解析了群落组成、多样性、稳定性及其对环境因子的响应。结果表明，水文连通的河流与太湖拥有相似的硅藻–蓝藻组合，多样性低但空间稳定性高；而相对孤立的池塘则以裸藻和甲藻为主，多样性更高、季节稳定性更强，但空间异质性显著。OMI分析显示，池塘的生态位重叠度（40%）高于太湖（19%）和河流（23%），反映出对稳定环境的趋同适应。浮游植物多样性在总氮约为2.7 mg/L时达到峰值，超过该浓度后蓝藻的优势地位抑制了多样性。太湖和河流中的蓝藻生物量对气温高度敏感，而池塘的响应极小；在SSP5-8.5情景下，预计到2100年太湖和河流的蓝藻生物量将分别增加0.51 mg/L和0.43 mg/L。即便在高强度富营养化压力下，水文连通性仍可塑造浮游植物组成及其对环境变化的敏感性，这要求在这些区域必须实施针对不同水体类型的管理策略。

（来源：Water Research 2026  DOI: 10.1016/j.watres.2026.125344）