Abstract: In order to understand the biological purification processes in wetland ecosystem, the soil phosphatase activity (PA) in shorefront of Baiyangdian wetland was determined, and the effects of related environmental factors including water level fluctuation, water temperature, and soil nutrient substrates were analyzed. It was found that the grey associated coefficient of soil PA with water level and water temperature was 0633 and 0619, respectively, suggesting that soil PA was significantly affected by the two environmental factors. Variance analysis showed that the soil PA in the shorefront had a greater seasonal fluctuation than that in the mesotrophic zone, indicating that the biodegradation of phosphoesters was affected by the nutrient substrates in wetland soil. A linear regression model of PA and major environmental factors was established, which could be used for the simulation and assessment of the wetland purification capacity.

Key words: Shellfish, Carrying capacity, Suitable culture area, Dadeng Island sea area