作者：Li, Y., Li, X., Niu, L., Hu, J., Zhang, W., Lin, L. & Zhang, W.

Urban river-lake interfaces are crucial areas for substance migration and transformation, and prone to algal blooms. However, the phosphorus (P) cycle in urban river-lake interfaces has not been comprehensively investigated, especially for the mineralization and solubilization processes of phosphorus driven by phosphorussolubilizing bacteria (PSB). In this study, we investigated the distribution characteristics of PSB, including inorganic P solubilization bacteria (IPB) and organic P mineralization bacteria (OPB), along the river-estuarylake continuums of typical urban river-lake interfaces in Taihu Lake, China. Results showed that the concentrations of relatively recalcitrant P fractions (Ca-IP and OP) in sediments did not increase, but Fe/Al-IP increased significantly along the river-estuary-lake continuums. Though the community diversity and structure of both OPB and IPB showed insignificant differences along the continuums, their assembly mechanisms and ecological roles varied obviously among three regions. PSB communities presented the highest deterministic assembly process in estuaries (41-47%), with the homogenous selection 2-7% higher than that of total bacteria. Co-occurrence network analysis revealed that PSB played a significantly increasing role in keeping module con-nectivity along the continuums, and accounted for the community stability in estuaries via the highest negative co-occurrence pattern (53%). Besides, the proportion of single OPB in PSB was much higher in estuaries and the lake than that in rivers. The average abundance of OP mineralization genes increased along the typical con-tinuum, but IP solubilization genes was highest in estuaries, followed by rivers. The results suggested varied PSB-mediated P transformation processes along the continuums, with rivers dominated by IP solubilization, estuaries enhanced by both IP solubilization and OP mineralization, and the lake enhanced by OP mineralization. Mantel test, PLS-SEM and machine-learning models elucidated that velocity, wNH4+and sTOC were probably the primary factors affecting PSB community and P fractions in urban river-lake interfaces. These findings provided a new insight for understanding P cycle in urban river-lake interfaces.

城市河湖界面是物质迁移转化的关键区域，且易发生藻华。然而，城市河湖界面中的磷循环，特别是解磷菌驱动的磷矿化与溶解过程，尚未得到全面研究。本研究以中国太湖典型城市河湖界面为对象，沿河流—河口—湖泊连续体调查了解磷菌的分布特征，包括无机磷溶解菌和有机磷矿化菌。结果表明，沉积物中较难转化的磷形态（钙结合态无机磷和有机磷）的含量沿连续体并未升高，而铁/铝结合态无机磷则显著增加。尽管有机磷矿化菌和无机磷溶解菌的群落多样性与结构沿连续体无显著差异，它们的群落构建机制与生态角色在三个区域间差异明显。在河口，解磷菌群落表现出最高的确定性组装过程（41–47%），其同质选择比例较总细菌高出2–7%。共现网络分析显示，解磷菌在维持模块连通性方面的作用沿连续体显著增强，并通过最高的负共现比例（53%）在河口维持了群落稳定性。此外，河口和湖区解磷菌中单一有机磷矿化菌所占比例远高于河流。有机磷矿化基因的平均丰度沿典型连续体递增，而无机磷溶解基因丰度在河口最高，河流次之。这些结果表明，解磷菌介导的磷转化过程沿连续体有所不同：河流以无机磷溶解为主，河口同时增强无机磷溶解与有机磷矿化，而湖区则以有机磷矿化增强为主。Mantel检验、偏最小二乘结构方程模型及机器学习模型表明，流速、水体铵态氮和沉积物总有机碳可能是影响城市河湖界面解磷菌群落与磷形态的主要因子。上述发现为理解城市河湖界面中的磷循环提供了新认知。

（来源：Water Research 2026  DOI: 10.1016/j.watres.2026.125392）