Origin data

The release of phosphorus (P) from sediments is a pivotal factor in the eutrophication of floodplain lakes, making it essential to understand the driving factors for effective management. However, the influence patterns of changes in environmental and microbial characteristics caused by seasonal and spatial variations on phosphorus release from sediments remain unclear. This study examines the floodplain system to explore the release risk and causes of sedimentary phosphorus in two seasons through sequential extraction of sediment phosphorus, phosphorus isotherm adsorption experiments, degree of phosphorus saturation (DPS) experiments, qPCR and gene sequence analysis. The results indicated that the zero equilibrium phosphorus concentration (EPC₀) of sediments was 13.46 folds in dry season and 6.29 folds in wet season higher than water soluble reactive phosphorus (SRP) content, respectively, while the maximum phosphorus adsorption capacity (Q_max) exhibited little differences between two seasons. On the whole, seasonal and spatial variations indirectly affected the fractions changing and release potential of sediment phosphorus by altering environmental variables and microbial phosphorus-cycling fucntions. Particularly, The properties of water (DO, pH, TP, NH₄⁺) and sediments (TOC, TN) in dry season significantly affected microbial alpha and beta diversity, promoting the phosphorus fraction transformation (such as Ca-P dissolution and release) of sediments, thus affecting the phosphorus release potential (Q­_max, DPS). The water (T, SRP, TN, TP) and sediment (TOC, DOC, TN) properties of wet season influenced the phosphorus release potential (Q­_max, EPC₀) by enhancing microbial organic phosphate mineralization and inorganic phosphate solubilization. Therefore, sediments microbial communities in the floodplain lake responded rapidly to the characteristics of water and sediment. Regulating these indicators can help provide specific schemes for phosphorus management in floodplain ecosystems. Our research elucidated the key driving factors of endogenous phosphorus release in the floodplain lake with seasonal changing, and it provided important insights into future limnal protection efforts influenced by human activities and climate change.

沉积物磷（P）的释放是漫滩湖泊（floodplain lakes）富营养化的关键驱动因子，明确其影响机制对开展有效治理至关重要。然而，季节与空间变异引发的环境及微生物特征变化，对沉积物磷释放的影响模式仍未明确。本研究以漫滩系统为研究对象，通过沉积物磷连续分级萃取法、磷等温吸附实验、磷饱和度（DPS）实验、定量聚合酶链式反应（qPCR）及基因序列分析，探究了两个季节下沉积物磷的释放风险与成因。研究结果显示，沉积物的磷零平衡浓度（EPC₀）在枯水季与丰水季分别为可溶性活性磷（SRP）含量的13.46倍与6.29倍，而最大磷吸附容量（Qₘₐₓ）在两个季节间差异极小。总体而言，季节与空间变异通过改变环境变量与微生物磷循环功能，间接影响沉积物磷的组分转化与释放潜力。具体而言，枯水季的水体（溶解氧DO、pH、总磷TP、氨氮NH₄⁺）与沉积物（总有机碳TOC、总氮TN）特征，显著影响微生物的α多样性与β多样性，促进沉积物中磷组分的转化（如钙结合态磷Ca-P的溶解与释放），进而影响沉积物的磷释放潜力（Qₘₐₓ、DPS）。丰水季的水体（水温T、SRP、总氮TN、总磷TP）与沉积物（TOC、溶解性有机碳DOC、TN）特征，则通过增强微生物的有机磷矿化作用与无机磷溶解作用，影响沉积物的磷释放潜力（Qₘₐₓ、EPC₀）。因此，漫滩湖泊中的沉积物微生物群落可快速响应水体与沉积物的特征变化。调控上述指标可为漫滩生态系统的磷治理提供针对性方案。本研究阐明了季节变化下漫滩湖泊内源磷释放的关键驱动因子，为受人类活动与气候变化影响的未来湖沼保护工作提供了重要参考。