鄱阳湖2010—2019年氮磷收支及其富营养化影响

Nitrogen and phosphorus budget and eutrophication impacts in Poyang Lake from 2010 to 2019

通过对鄱阳湖氮、磷浓度的沿程变化监测,结合长时间序列历史观测数据,揭示了2010—2019年鄱阳湖流域氮、磷输送特征,并探讨了氮、磷收支对洪泛湖泊系统水生态健康的长期效应.结果表明:2010—2019年,鄱阳湖湖区总氮(TN)、总磷(TP)浓度呈增长趋势,湖区TN、TP净通量在-2.62×10^(8)~1.12×10^(8)kg和-2.25×10^(7)~1.28×10^(7)kg之间波动.五河中赣江的TN、TP输入通量最大,年均输入通量分别为1.50×10^(8)、1.01×10^(7)kg,湖口TN、TP年均输出通量分别为3.04×10^(8)和1.76×10^(7)kg.入湖五河TN、TP平均浓度是影响湖区水质和富营养化程度的重要因子.此外,本研究发现2010—2019年鄱阳湖水质从Ⅳ类水恶化至劣Ⅴ类水,富营养化程度由中富营养化加剧到富营养化.因此,持续控制入湖河流的TN、TP浓度对鄱阳湖水生态的治理修复具有重要意义.

This study monitored the changes in nitrogen and phosphorus concentrations along the Poyang Lake and combined long-term historical collection data to reveal the characteristics of nitrogen and phosphorus transport in Poyang Lake from 2010 to 2019,and explored the long-term effects of nitrogen and phosphorus budget on the water ecological health of the flooded lake system.The results showed that the concentrations of total nitrogen(TN)and total phosphorus(TP)in the Poyang Lake area increased from 2010 to 2019.The net fluxes of TN and TP in the Poyang Lake area fluctuated between-2.62×10^(8)~1.12×10^(8) kg and-2.25×10^(7)~1.28×10^(7) kg.Among the five rivers,Ganjiang River had the largest input fluxes of TN and TP,and the average annual input fluxes of TN and TP were 1.50×10^(8) kg and 1.01×10^(7) kg,respectively.The average annual output fluxes of TN and TP at the lake estuary were TN 3.04×10^(8) kg and 1.76×10^(7) kg respectively.The average concentration of TN and TP in five rivers were important factors affecting water quality and eutrophication degree.In addition,the study found that from 2010 to 2019,the water quality of Poyang Lake deteriorated from Class IV water to poor class V water,and the degree of eutrophication increased from medium to eutrophication.Therefore,the continuous control of TN and TP concentration of rivers entering the lake is of great significance to the water ecology management and restoration of Poyang Lake.