Manganese(III) dominants the mobilization of phosphorus in reducing sediments: Evidence from Aha reservoir, Southwest China

• Published in: The Science of the total environment 2024-12, Vol.954, p.176564, Article 176564
• Main Authors: Chen, Quan, Wang, Jing-fu, Zhu, Meng-qiang, Qin, Hai-bo, Liao, Peng, Lu, Zhi-tong, Ju, Peng-cheng, Chen, Jing-an
• Format: Article
• Language: English
• Subjects: China; environment; Eutrophication; geochemistry; iron; manganese; Manganese(III); Mobilization mechanism; oxygen; Phosphorus; Reducing sediments; sediments; species; X-ray photoelectron spectroscopy
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.176564

Eutrophication has become one of the greatest threats to aquatic ecosystems. The release of phosphorus (P) from sediments exerts a critical role on eutrophication level. Both manganese (Mn) and iron (Fe), sensitive to redox conditions, own strong affinity for P. Numerous works have demonstrated that Fe was a key factor to drive P cycle in sediments. However, the role of Mn on P mobilization remains largely unexplored. Herein, the mechanism of P mobilization driven by Mn were investigated in a seasonal anoxic reservoir. Diffusive gradients in thin films (DGT) results, from both field investigations and laboratory incubations, showed P was synchronously distributed and significantly positive correlated (r2 ≥ 0.40, p 99.2 %) in reducing sediments. This study significantly expanded our knowledge on the geochemical behavior of P influenced by Mn in aquatic sediments. [Display omitted] •Couple cycle between Mn and P were observed in reducing sediments.•P mobilization in reducing sediments was mainly driven by Mn(III).•Fe mainly deposited as inert Fe minerals leads the decoupled of P and Fe.•Updated P cycle patterns in different sedimentary environments were proposed.