Kerr,J.G., Burford,M., Olley,J. and Udy,J.(2011): Phosphorus sorption in soils and sediments: implications for phosphate supply to a subtropical river in southeast Queensland, Australia. Biogeochemistry, 102, 73-85.

『土壌と堆積物におけるリンの収着:豪州のクイーンズランド州南東部の亜熱帯河川へのリン酸塩供給との関係』


Abstract
 Phosphorus (P) is often a key limiting nutrient in freshwater systems, and excessive P can result in algal blooms, with flow-on effects to aquatic food webs. P sorption is an important process in aquatic and terrestrial ecosystems whereby phosphate (PO43-) is exchanged between liquid and solid phases. This study shows that differences in the concentration of PO43- in a subtropical river system during high and low flow can be attributed to differences in P sorption characterises of its catchment soils and sediments. The sediments have lower Equilibrium Phosphate Concentrations (EPCo) and higher binding energy (Kd); the surface soils have higher EPCo and higher easily desorbed P (NH4Cl-P). A comparison of filterable reactive phosphorus (frP) in water samples collected at high and low flows, with soil and sediment EPCo, suggested that during event flows, the high EPCo and NH4Cl-P of surface soils is producing a net movement of PO43- from the soil/sediment system into runoff and stream flow. At baseflow, there is more likely a net movement of PO43- into the riverbed sediments. This has important implications for management actions aimed at reducing P loads to river systems and downstream water storages, namely the need to increase the infiltration of rainfall to decrease the amount of PO43- being flushed from the surface soil.

Keywords: Equilibrium phosphate concentration; Phosphorus; Rivers; Sediment; Soil』

Introduction
Methods
 Study area
 Study sites and sampling
 Sediment characteristics
 Sequential extraction
 Phosphorus sorption
 Statistical analysis
Results
 Phosphorus fractionation of sediments and soils
 Phosphorus sorption in sediment and soil
 Comparison of the EPCo of soils and sediments with water column frP under event flow and baseflow conditions
 Comparison of NH4Cl-P pools, P sorption capacity and annual frP loads in the UBR catchment
Discussion
Conclusion
Acknowledgments
References


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