Contributions of phosphorus on sedimentary phosphorus bioavailability under sediment resuspension conditions

The contributions of phosphorus (P) to the bioavailability of sedimentary P under sediment resuspension conditions were evaluated using water soluble P, readily desorbable P, algal available P, and NaHCO3-extractable P. Sediment resuspension resulted in a more efficient removal of dissolved inorganic P from the overlying water. As such, the incorporation of P into the sediments was greater under this condition compared with the static condition. The amount of bioavailable P extracted by each method and the proportion of each to the total P (Tot-P) in both sediments with and without resuspension varied. The contributions of input P to P bioavailability under sediment resuspension conditions were considerably lower than those under static conditions. A possible explanation for this is the strong oxidation and the higher contact probability between P and P reactants, such as crystalline iron, aluminum oxides, and organic matter, as a result of sediment resuspension. The amounts of bioavailable P and their proportions to Tot-P in sediments of Lough Erne (deep) and Lake Taihu (shallow) can verify these hypotheses.