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| Effects of environmental factors on nitrogen exchange flux at the sediment-water interface in the water level fluctuation zone of Miyun reservoir |
| Received:September 13, 2021 |
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| KeyWord:fluctuation zone;sediment-water interface;environmental factor;exchange flux |
| Author Name | Affiliation | E-mail | | LIU Yahe | College of Resources, Environment and Tourism, Capital Normal University, Beijing 100048, China | | | WANG Xiaoyan | College of Resources, Environment and Tourism, Capital Normal University, Beijing 100048, China
Research Center of Aquatic Environment in the Capital Region, Capital Normal University, Beijing 100048, China | wangxy@cnu.edu.cn | | XU Kangli | College of Resources, Environment and Tourism, Capital Normal University, Beijing 100048, China | |
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| Abstract: |
| To investigate the response of nitrogen at the sediment-water interface in the water level fluctuation zone under different environmental conditions（e.g., temperature, pH, and dissolved oxygen）, a static culture experiment was conducted in an undisturbed mud column using sediment and water samples collected from the Miyun reservoir. The results were as follows：the inorganic nitrogen content of the sediment and overlying water in the fluctuation zone was significantly different in summer（dry period）and autumn（flooded period）. Among them, the NH4+-N content of the sediment showed the greatest change, decreasing by 80.4% in autumn compared with summer, while the NO3--N content decreased by 59.7% in autumn. Tri-state nitrogen（NH4+-N, NO2--N, NO3--N）was released into the water from the sediment during flooding. Temperature, pH, and dissolved oxygen had different effects on the migration and transformation of nitrogen at the sediment-water interface in the fluctuation zone. Increasing the temperature promoted the release of NH4+-N and inhibited the release of NO3--N. Acidic and alkaline conditions promoted the release of NH4+-N. Aerobic conditions intensified the exchange of tri-state nitrogen at the sediment-water interface and aggravated the release of three-state nitrogen. The C / N ratio（7.51~9.35）of sediment indicates that organic matter in the surface water is mainly derived from biological residues in the water. Therefore, attention should be paid to the risk of endogenous release by sediments in the fluctuation zone of the Miyun reservoir in the future, and the construction of wetlands should be improved to reduce the pollution caused by nitrogen loss in the fluctuation zone. |
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