Inland wetlands play a crucial role in removing basin non-point nitrogen load through denitrification and anaerobic ammonium oxidation(anammox).To investigate the effects of different human activities on denitrification rates of wetland sediments,we collected surface sediment cores and overlying water samples from typical lake wetlands influenced by human activities in Jiashan county,China,and measured the denitrification and anammox rates using15N isotope tracer technique.Our results showed that denitrification was the dominant nitrogen removal pathway in Jiashan,accounting for an average of 82.34％of the total nitrogen removal,while anammox had a minor contribution.The denitrification and anammox rates varied significantly among wetlands affected by different human activities.The highest denitrification rates were observed in wetland sediments influenced by residential and agricultural activities,with mean values of(40.39±1.89)pmol/(Ng·h)and(35.26±2.99)pmol/(Ng·h),respectively.The anammox rate was significantly higher in wetland sediments influenced by aquaculture,with a mean value of(5.67±0.57)pmol/(Ng·h).The main environmental factors affecting these processes were NH4+-N,Chl.a,NO3--N and pH in the water.Overall,nitrogen removal efficiency in Jiashan County are significantly affected by human activities.In the future,when assessing the ecosystem service functions of regional wetlands,the impacts of various anthropogenic disturbances should be comprehensively taken into account.
维普
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