Study On The Correlation Between Sediment And Greenhouse Gas Production And Absorption In The Middle Section Of The Three Gorges Reservoir

In this study,the middle section of the Three Gorges Reservoir was selected,and Fuling,Zhongxian and Wanzhou were identified as typical sections for this study,and a hydrological year was observed.The sediment-water interface of the monitoring site was selected as the research object,and the indicators of the sediment(particle size distribution,saturated water content,organic carbon content,total nitrogen,ammonia nitrogen,and?NO₃^--N?,overlying water were monitored.The water ecological indicators?TOC,TN,NH₄⁺-N and NO₃^--N?,environmental factors?pH,temperature and DO?and greenhouse gas partial pressure?CO₂ and CH₄?form the spatial and temporal changes of various indicators.Data between sediments,data between overlying waters,and correlations between data between sediment-water interfaces and greenhouse gases.In the middle part of the Three Gorges reservoir area,the partial pressure of methane at the sediment-water interface is affected by the influence of nitrogen on the interface,which is significantly affected by organic carbon.The CH₄ of the three monitoring points in this study has a direct correlation with the overlying water TN,the overlying water NO₃^--N,the pH value and the mean size of sediment,while the indirect correlation with the sediment-water interface is the total nitrogen and NH₄⁺-N in the sediment.NO₃^--N and organic carbon.This may be due to the fact that the nitrogen element at the sediment-water interface is an important element in the growth and physiological metabolism of methanogens and methane oxidizing bacteria in the sediment,and the organic carbon is always in an excess state,leading to a correlation analysis with the partial pressure concentration of CH₄.The results did not produce a direct correlation,but there was an indirect relationship between the overlying water NO₃^--N.The direct correlation with the partial pressure of CO₂ is the overlying water TN,the sediment nitrogen,the sediment NH₄⁺-N,DO and temperature,and the indirect correlation with the sediment-water interface.The total nitrogen and NH₄⁺-N in the sediment.,NO₃^--N and TN,NH₄⁺-N overlying water.In addition,DO,pH and CO₂ have this synergistic change in a certain range and interact with each other.The concentration of DO has a significant enhancement effect on the production of carbon dioxide at the sediment-water interface.The sufficient DO and the aerobic bacteria that are beneficial to ammoniated bacteria are not only in the increase of DO concentration but also accompanied by a large amount of The consumption of organic carbon is presumed to bring about a stronger respiration,while the concentration of DO has a significant effect on the nitrogen element at the sediment-water interface.In addition,the pH condition affects the degree of dissociation of natural organic matter,and can change the morphology of organic matter in the water ecological environment,so that the degree of protonation of the organic matter is enhanced,and the interface becomes the starting point of organic matter enrichment and sedimentation.