淀山湖沉积物-水界面氮磷通量及其生态环境效应研究

底泥营养盐释放对淀山湖湖区造成的内源污染不容忽视.采用室外采样和室内模拟实验方法,对春夏两季淀山湖沉积物-水界面氮磷释放速率进行了研究.结果表明春季氨氮、硝态氮、可溶磷的的通量变化范围分别为-692.79~315.82 mg/(m2?h)、-19.04~5.29 mg/(m2?h)和-1.35~2.31 mg/(m2?h),平均值分别为76.65 mg/(m2?h)、-3.29 mg/(m2?h)和0.64 mg/(m2?h).夏季三者变化范围分别为-74.15~91.91 mg/(m2?h)、-70.71 mg/(m2?h)~8.65 mg/(m2?h)和-10.02~18.86 mg/(m2?h),平均值为4.85 mg/(m2?h)、-42.16 mg/(m2?h)和9.47 mg/(m2?h).淀山湖区春夏两季总氮(TN)、总磷(TP)的交换总量分别为-1769.22 t,1539.40 t,淀山湖底泥可以有效去除上覆水体氮负荷,但却是水体磷的释放源.

Benthic Flux of Nitrogen and Phosphorus Across Sediment-water Interface in Dianshan Lake and Its Eco-environment Benefit

The endogenous pollution caused by the release of nutrient in Dianshan Lake cannot be ignored. This research, per-formed in Dianshan Lake, aimed to estimate the benthic flux of Nitrogen and Phosphorus during spring and summer with the method of outdoor sampling and indoor simulation experiments. Results showed that benthic flux of ammonia nitrogen, nitrate nitrogen and PO3-4 -Pvaried from -692. 79 to 315. 82 mg/( m2?h) ( with mean value of 76. 65 mg/( m2?h) ) , -19. 04 to 5. 29 mg/( m2?h) ( with mean value of -3. 29 mg/( m2?h) ) and -1. 35 to 2. 31 mg/( m2?h) ( with mean value of 0. 64 mg/( m2?h) ) in spring. While benthic flux of ammonia nitrogen, nitrate nitrogen and PO3-4 -Pvaried from -74. 15 to 91. 91 mg/( m2?h) ( with mean value of 4. 85 mg/(m2?h)),-70. 71 to 8. 65 mg/(m2?h)(with mean value of -42. 16 mg/(m2?h)) and -10. 02 to 18. 86 mg/( m2?h) ( with mean value of 9. 47 mg/( m2?h) ) . After interpolation, it can be calculated that the total exchange rate of total ni-trogen ( TN ) and total phosphorus ( TP ) across sediment water interface are -1769. 22t and 1539. 40t during spring and summer in Dianshan Lake. The research showed that sediment can effective-ly cut down nitrogen loading rate of overlaying water but also be the releasing source of phosphate in Disnshan Lake.