Study on spatial-temporal distribution of different forms of phosphorus in wetland sediments

Abstract

As an important factor for controlling phosphorus adsorption and release in wetland system, the forms of phosphorus in sediment has a decisive effect on phosphorus retention and release. Four different wetland systems were selected to study the phosphorus status and its environmental effects in wetland sediment. Phosphorus forms in sediments were related to aquatic plant characteristics. In the Vallisneria Linn. wetland system, the content of Ca-P of sediment was higher than the other systems because of its higher pH of the water. The maximum phosphorus adsorption capacity is 766.82-840.27 mg/kg. The content of Ca-P and TP have very good correlation with Smax. When the phosphorus concentration in the water is lower than 0.1mg/L, the surface sediment is no longer a “sink” of phosphorus but a “source” of phosphorus. The changes of TP in four wetland sediments basically follow a similar trend. The phosphorus content in the sediment decreased during the growth period of aquatic plants, and the wetland sediment as the phosphorus “source” provided the biomass for the growth of the aquatic plants. In autumn and winter, phosphorus in plants is released into wetland again with the decay of plants, resulting in the increase of phosphorus content in sediment.