Exploration of Phosphorus Release Characteristics in Sediments from Plains River Network: Vertical Distribution and the Response of Phosphorus and Microorganisms

Abstract

River networks are important natural ecosystems that play an important role in water storage, drainage, water conservation and water purification. This study analyzed the vertical distribution of each form of phosphorus, the vertical distribution of the microbial community, and the response between the two in the sediments of this plain river network. The results showed high sediment TP concentrations (633.9-2534.7 mg/kg) in this plain river network. The vertical distribution trend of Fe-P was almost the same as that of TP and had the highest concentration (134.9-1860.1 mg/kg). Ca-P is the second highest phosphorus content, which is also an inert phosphorus component as well as Al-P, and both exhibit a relatively low percentage of surface layers. Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria showed heterogeneity in the vertical distribution of sediments. The river network sediments in the plains have a high potential for phosphorus release, with most sites acting as phosphorus "sources". The sediments in the second of these layers show a strong tendency to release phosphorus. Bottom sediments have a low capacity to both adsorb and release phosphorus. This study will provide some theoretical support for the prevention and management of river networks in this plain.

Keywords: Sediment, Phosphorus release, Microorganisms, Phosphorus, Vertical distribution