Phosphorus fraction and phosphate sorption-release characteristics of the wetland sediments in the Yellow River Delta

Publication date: Available online 5 June 2017 Source:Physics and Chemistry of the Earth, Parts A/B/C Author(s): Yuan Cui, Rong Xiao, Ying Xie, Mingxiang Zhang The aim of this study was to investigate phosphorus (P) fractions and phosphate sorption-release characteristics of the surface sediments regarding the wetland restoration in the Yellow River Delta (YRD). Sediments samples were collected from three typical sample plots: Phragmites australis community (p), Suaeda salsa community (s), and bare land (b) both in natural wetland (N) and restored wetland (R). The results showed that the mean content of TP was 541.58 mg/kg, and the rank order of P fractions were: inorganic phosphorus (IP) (65.6%) > residual phosphorus (RP) (24.9%) > organic phosphorus (OP) (9.5%). For sediments under the same land cover, TP and OP contents were significantly higher in natural wetlands than those in restored wetlands. This indicated that the restoration project really made a difference in TP content of sediments, and the decreased TP might result from decreased OP. For P kinetics sorption, a quick sorption mainly occurred within 0.5 h. The maximum phosphorus adsorption capacities (Q max) ranging from 139.40 mg/kg to 224.06 mg/kg and the bonding energy constant (K) ranging from 0.33 mg/L to 1.37 mg/L were both obtained using a Langmuir model. In addition, Q max, P release (P r) and P release rates (P rr) were in the order of Nb > Np > Ns > Rb > Rp...
Source: Physics and Chemistry of the Earth, Parts ABC - Category: Science Source Type: research