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.