梁子湖表层水氮的季节变化与沉积物氮释放初步研究

Seasonal Dynamics of Nitrogen in Water and Release of Nitrogen from Sediment in Liangzi Lake

采用室内模拟的方法研究梁子湖沉积物N在pH值和温度控制下释放的特征.研究表明,梁子湖的入水口和出水口由于沉积环境影响到N的形态,其N的释放明显较湖心高,在试验初期由于搅动的影响使得N的释放在第1天较第2、3天高,其后则迅速增加释放量.温度对N释放影响明显,30℃条件下N释放曲线的峰值较4℃条件下高近1倍,20℃条件下N释放曲线的峰值较4℃条件下高30%.pH值对沉积物N释放同样有明显的影响.在偏酸(pH 5.5)和偏碱(pH 11.5)条件N的释放量较湖水正常pH值(pH 8.5)增大.湖水全N含量在0.180～1.362 mg/L之间,平均0.713 mg/L;NH4+-N含量在0.023～0.130 mg/L之间,平均含量为0.065 mg/L;硝态N在0.005～0.72 mg/L之间,平均含量为0.257 mg/L.梁子湖表层水中氮含量呈明显的季节性变化,全N和NO3--N是春季高,冬季低;NH4+-N是春季含量最高,而夏季含量最低.

The Nitrogen content in water body and N release from sediment in Liangzi lake was studied in this paper. The results showed that the content of N in water body had an obvious seasonal dynamics, the highest content of total N and NO3^--N in spring, the lowest content in winter. But for NH4^＋-N, the highest content in spring, the lowest content in summer. In laboratory condition , the effect of temperature and pH on N release from sediment. It was found that temperature and pH play important role for N release was studied. High temperature promoted the N release from sediment. The maximum value of N release under 30 ℃ and 20 ℃ condition was significantly more than that under 4 ℃ condition. Change of pH of water body increased the amount of N release from sediment.