Sorption dynamics, geochemical fraction and driving factors in phosphorus transport at large basin scale

Abstract The transport and deposition of phosphorus (P) in large-scale basin are closely associated with the spatial distribution characteristics and nutritional status of river sediments. Samples of surface water (SW), suspended sediment (SS), bed sediment (BS), and sediment cores from the Yellow River (YR) were collected. The different fractions including total phosphorus (TP), organic P (OP), inorganic P (IP), HCl–P and NaOH–P were determined by standard measurement and testing method. The results showed that upper, middle, and downstream sedimentary texture exhibit spatial heterogeneity. Pearson correlation analysis and redundancy analysis revealed that medium grain size (Mz) is the most negative factor that influence P and fractions, indicating the importance of silt content. Additionally, TP and HCl–P content were positively and significantly correlated, and the calculated correlation coefficient was 0.96 (p