Abstract: In the present study, Puzhehei karst wetland, located in the southeast of Yunnan, was selected as the research area, and typical sample plots were also set to determine the contents of different speciation of phosphorus and the distribution characteristics of total phosphorus (TP) and different phosphorus speciation (Ca₂-P, Ca₈-P, Ca₁₀-P, Al-P and O-P) in the area of paddy wetland, meadow wetland and lakeside wetland, as well as the correlation analysis among phosphorus speciation. It was shown that the contents of total phosphorus exhibited large variations in the sediment of paddy wetland,meadow wetland and lakeside wetland, which followed the sequence of paddy wetland>lakeside wetland>meadow wetland. Ca-P was the main form of phosphorus speciation in sediments, and the Ca₁₀-P showed the highest proportion in Ca-P. The spatial distribution characteristics of Ca₂-P, Ca₈-P, O-P, Ca₁₀-P were consistent with that of TP. In the vertical direction, the distribution of each phosphorus speciation showed the highest concentrations in the surface layer (0-5 cm) of the sediments in lakeside wetland and decreased with the increasing depth. Each of the phosphorus speciation was positively correlated to TP in sediment, and Ca₂-P and Al-P were significantly correlated to TP.

Key words: Puzhehei, karst wetland, sediment, phosphorus speciation