Key Driving Factors Of Greenhouse Gas Fluxes Under Diffrent Microhabitats In Ulansuhai Wetland

Wetland ecosystems is the main natural emission sources of the greenhouse gases such as CO₂,CH₄ and N₂O.Reducing greenhouse gas emissions from natural wetlands has attracted worldwide attention.The Ulansuhai Wetland is a representative wetland in the arid area of northern China.In this study,the release law of CO₂,CH₄ and N₂O fluxes in the lakeside zone of the Ulansuhai wetland was studied by indoor culture method.The correlation between soil physical and chemical indexes,microbial factors and greenhouse gas fluxes was comprehensively analyzed,and the main environmental driving factors of CO₂,CH₄ and N₂O fluxes were evaluated by linear mixed effect model.The main results are as follows:(1)There is obvious spatial heterogeneity of greenhouse gas fluxes in soils under different microhabitats in the lakeside zone of Ulansuhai wetland.The results showed that:for CO₂flux,vegetation community habitat emission flux>no vegetation;for CH₄ flux,soil matrix covered Suaeda glauca Bunge and Nitrwria sibirica Pall.was absorption sink of CH₄,other samples were emission sources of CH₄;for N₂O flux,the basic performance was vegetation community habitat emission flux>no vegetation,except Suaeda glauca Bunge.(2)The results of correlation analysis between greenhouse gas flux and soil physical and chemical indexes showed that TOC was significantly positively correlated with soil clay,CH₄ flux was significantly positively correlated with soil moisture,salinity and NO₃^--N were significantly positively correlated,NO₃^--N and NH₄⁺-N were significantly positively correlated.(3)The dominant microflora were Proteobacteria,Actinobacteriota,Chloroflexi,Firmicutes,Bacteroidota,Gemmatimonadota,Desulfobacterota,Acidobacteriota,Patescibacteria and Campilobacterota.CH₄and CO₂ fluxes were positively correlated with relative abundance of Chloroflexia,Desulfobacterota and Acidobacteriota,and negatively correlated with relative abundance of Actinobacteriota,Bacteroidota and Gemmatimonadota.N₂O flux was positively correlated with relative abundance of Proteobacteria and Patescibacteria.(4)Using linear mixed effects model analysis,it is concluded that non-biological factors such as soil salinity,PO₄^3-,NO₃^--N,water content and biological factors such as pmoA,nosZ and 16S rRNA gene abundance jointly affected CH₄ flux;non-biological factors such as NO₂^--N,TN,soil texture,TOC and biological factors such as pmoA,nosZ and 16S rRNA gene abundance jointly affected N₂O flux;non-biological factors such as soil salinity,PO₄^3-,NO₂^--N,TN,soil texture and biological factors such as pmoA and 16S rRNA gene abundance jointly affected CO₂ flux.