作者：Chen, J., Wang, H., Liang, D., Deng, Y., Liu, L., Xu, H., Zeng, Y., Li, S. & Li, J.

Understanding the evolving patterns of total phosphorus (TP) flux balance in freshwater ecosystems is essential for effective water environment management and planning. Extreme hydrological events driven by climate change have notably altered lake hydrodynamics, yet the TP flux response in river-connected lakes remains unclear. This study investigates the temporal evolution of TP flux in Poyang Lake from 2003 to 2022 based on hydrodynamic analysis, and quantifies the impact of extreme floods and droughts on the TP balance. The contribution of extreme floods to the annual average TP inflow and outflow was 18.42 % and 4.53 %, respectively, while that of extreme droughts dropped to 6.08 % and 9.06 %. We defined Flood Onset Abruptness Rate (FOAR) and Comprehensive Drought Index (CDI) to describe how tributaries respond differently to extreme events. Notably, the Rao River, characterized by short-duration and high-intensity floods, exhibited a flood-induced increase in annual average TP inflow of up to 35.45 %, while showing limited sensitivity to drought conditions. Net TP fluxes in Poyang Lake shifted from net inflow to net outflow, and eventually stabilized at a persistent net inflow condition between 2007 and 2020, with a mean annual net flux of 1.47 x 106 kg, 92.7 % of which was attributed to extreme flood events. These findings highlight extreme floods as a primary driver of TP imbalance in large river-connected lakes and provide new insights into phosphorus cycling under intensifying extreme flood and drought regimes.

理解淡水生态系统中总磷（TP）通量平衡的演变模式，对于有效的水环境管理与规划至关重要。气候变化驱动的极端水文事件已显著改变了湖泊水动力状况，然而通江湖泊中总磷通量的响应仍不明晰。本研究基于水动力学分析，探究了2003年至2022年间鄱阳湖总磷通量的时间演变，并量化了极端洪水与干旱对总磷平衡的影响。极端洪水对年均总磷流入量和流出量的贡献率分别为18.42%和4.53%，而极端干旱的贡献率则降至6.08%和9.06%。我们定义了洪水起始突变率（FOAR）和综合干旱指数（CDI），以揭示各支流对极端事件的不同响应方式。值得注意的是，以短历时、高强度洪水为特征的饶河，其洪水导致的年均总磷流入量增幅高达35.45%，而对干旱条件则表现出有限的敏感性。鄱阳湖净总磷通量由净流入转为净流出，并最终在2007至2020年间稳定于持续净流入状态，年均净通量为1.47×10⁶ kg，其中92.7%归因于极端洪水事件。这些发现凸显了极端洪水是大型通江湖泊总磷失衡的主要驱动因素，并为日益加剧的极端洪旱情势下的磷循环提供了新的认知。

（来源：Journal of Hydrology 2026  DOI: 10.1016/j.jhydrol.2025.134865）