白洋淀湿地氮素转化和N2O排放特征研究

通过对华北地区最大的湖泊湿地白洋淀近1年的野外观测，对湿地上覆水、沉积物/土壤中各种形态氮以及反硝化作用产物N2O排放通量的时空变化进行了系统研究。研究结果表明，白洋淀湿地对氮素污染物铵态氮的去除能力较强，平均去除率为77.1%。湿地中氮素的迁移转化过程时空变化明显，夏季是其氮素转化的快速期。湿地是温室气体N2O的排放源，夏季其排放通量最大，占全年排放通量总和的62.1%。其中湖滨带是整个湿地生态系统中氮素转化的活跃区，N2O年内平均排放通量高达109μg·m-2·h-1。由此可见，良好的湖滨带有利于湖泊富营养化的自然恢复。

Study on nitrogen transformation and N2O emission flux in Baiyangdian wetland

The biochemical transformation process of nitrogen in the Baiyangdian wetland was investigated by means of in situ monitoring. The spatial and temporal variation of various forms of nitrogen in water and sediment/soil as well as the N_2O emission flux in one year were measured and analyzed. The results indicate that the wetland is capable of effectively removing the ammonium nitrogen with efficiency 77.1％. The temporal and spatial variation of the nitrogen transformation in the wetland is remarkable. The whole wetland is the releasing source of N_2O and the nitrogen transforms quickly in summer. The N_2O emission flux in summer is 62.1％ of the total flux in a year. The littoral zone is the most active area contributing the most part of N_2O flux. It implies that a good littoral zone system is very important to the eco-environment restoration of the Baiyangdian Lake.