Soil Microbial Diversity And Anaerobic Oxidation Of Denitrifying Methane In Coastal Wetlands Of The Yellow River Delta

Microorganism and vegetation are the core elements of wetland ecosystem function,which affect the evolution,health and balance of wetland,high biodiversity is conducive to promoting the health and stability of wetland ecosystem.The Yellow River Delta wetland is located in the active transition area of sea and land,and has rich biodiversity,which is a natural place to study the relationship between microbe,plant and environmental factors.Wetlands are an important natural source of CH₄ emission,and the mechanism of CH₄ emission is influenced by both microorganisms and plants.The study taked the coastal wetland of the Yellow River Delta as the object,through modern sequencing technology to analyzed the soil microbial community structure under different vegetation in Spring and Autumn,revealed the spatial and temporal changes of environmental factors and microbial community structure in this region,and used stable isotope tracer test and molecular biology methods to analyzed the DAMO rate and the abundance of functional microflora NC10 in different environments.The main conclusions are as follows:(1)In Spring and Autumn,the soil p H in vegetated area was significantly lower than that in bare beach,and the contents of hydrolytic nitrogen and nutrient elements(total phosphorus,total potassium and total sodium)were generally higher than that in bare beach.Hydrolytic nitrogen content in Spring was higher than that in Autumn,but nutrient elements content was lower than that in autumn.The contents of SO₄^2-,NO₃^-and NO₂^-showed an overall pattern in Suaeda glauca(S.glauca)area>Bare area>Tamarix chinensi(T.chinensi)area>Phragmites australis(P.australis)zone.(2)In Spring,the order of soil microbial structure and abundance is T.chinensi and P.australis mixed area,T.chinensi area,S.glauca area,and overflowing beach area.In Autumn,the order of microbial structure and abundance is P.australis area,S.glauca area,T.chinensi area,oil area,and overflowing beach area.Clustering heat map analysis showed that the microbial composition and bacterial abundance in spring and autumn soil samples were clustered into two clones at both phylum and class levels,showing spatial and temporal differences.(3)RDA analysis of microbial community structure and soil factors showed that NO₃^-,NO₂^-,Fe³⁺,Mn⁴⁺,TK and Na were the important factors affecting the distribution of dominant microbial community in spring,and the main influencing factors in autumn were TP,hydrolytic nitrogen,p H,NO₃^-,NO₂^-and Na.(4)The stable isotope tracer showed that the soil DAMO rate was different under four different vegetation types.The highest DAMO rate was in the P.australis area(0.99±0.03?3.8±0.11 nmol CO₂^-1d^-1),followed by the tamarissima area(0.8±0.05?1.12±0.07 nmol CO₂^-1d^-1),the S.glauca area(0.72±0.12?2.51±0.07),and the sea plain area(0.55±0.04?1.97±0.11 nmol CO₂^-1d^-1).Quantitative PCR results showed that the16S r RNA gene abundance of NC10 in the four soils was the highest in S.glauca area(3.08×10⁷?8.56×10⁷ copies g^-1),and sea flooded area(2.76×10⁶?1.35×10⁷ copies g^-1).(5)Pearson correlation analysis results showed that nitrate/nitrite and TN were the main environmental factors affecting the rate of DAMO,electrical conductivity was negatively correlated with the rate of DAMO,ferric,tetravalent manganese and sulfate were the main environmental factors affecting the process of AOM.