Spatial Distribution And Driving Factors Of Soil Bacterial And Ammoxidation In A Typical Islet Wetland Of Poyang Lake

The Poyang Lake islet wetland is a transitional border between land and aquatic ecosystems,and were actived with the climate,hydrology and human activity and they exhibit natural environmental gradients.The knowledge about how the microbial community structure and function respond to different level elevation is significant in this study,according to the different elevation and the distribution of vegetation's succession.Therefore,the research of the relationship between microorganism and environmental factors,help us to explore wetland ecosystem response to climate change.This study selected the Bang Lake,which is one of the most representative in the Poyang Lake wetland ecosystem.From the shore to center of Bang Lake,these five plots referred to as S1,S2,S3,S4,S5.The horizontal distance between S1 to S5 of 2.1 km,and combined with underground 0-20 cm,20-40 cm,40-60 cm,60-80 cm,80-100 cm.Firstly,the spatial distribution of soil physichemical properties was described and analyzed.The second,spatial distributions of bacterial and Ammonia oxidizing bacteria?AOB?and Ammonia oxidizing archaea?AOA?community was measured by q-PCR,16S rRNA high throughout sequencing and Clone library,T-RFLP,respectively.And the soil microbial function were evaulated.The relationship between soil environmental factors,soil microbial community and soil function activities were discuss the influence of environment change on the wetland ecological functions.1.The main conclusion are as follows Soil properties,bacterial microbial and ammonia-oxidizing microbial community and functional characteristics are significantly different as the horizontal.It appears to be:?1?Soil properties were significant differences between S1-S2 and S3-S4,S5 as one cluster,respectively.?2?The distribution of soil bacteria communities were successively adjacent plots was more obvious.The plots S1,S2,S3 clustered together,while the plots S4,S5formed the other clade,while the relative abundance of communities were dominated by Acidobacteria and Chloroflexi,respectively.?3?Accroading to the sites S1 to S5,the AOA and AOB were founded obviously niche differentiation,the formation of the continental area of sample S1,S2 and sample S4-S5 and sample area in the middle of the S3.The dominant species of the S1-S2 is Nitrosotalea cluster Group,1.1a associataed,and the dominant species of S4-S5 in the center of the lake is Nitrospumilus cluster?sediment?.AOB dominated the S4-S5 of the lake center,and the dominant species were all Cluster 2.3 Nitrosospira.2.The microbial functional activities were significantly different on both horizontal and vertical scales,as follows:?1?The horizontal and vertical distribution of the soils of the wetland soil is remarkable,and it is largely affected by the surface of the floating mold and the GAL15,and it has nothing to do with the main superior bacteria species.?2?In the vertical gradient,only the subface soil layers?0-40cm?PNA content was significantly larger than?40-100cm?deep soil.But there was no significant change in the microbial community of amoA gene communitys.3.soil pH is the important environmental factor affecting the soil microbial community and functional activity of wetland in poyang lake,followed by soil nutrient salt?NH₄⁺-N,AFDM,TN,TOC?.In conclusion,the results show that Poyang Lake wetland was forming intermediate niche differention scales for microbial community,and soil pH is the main environmental driving factors.In the sample sites S1-S2,formation of the land zone has led to the dominance of Acidobacteria and AOA.In the sample sites S4-S5,the formation of the lake zone,which promotes the high relative abundance of AOB and Chloroflexi,and increasing the diversity of microbial community and the ability of soil ammonia-oxidation.The middle sample S3 is a transitional characteristic and property.The research findings provide scientific basis for predicting the response of wetland ecosystem to future environment changes,and supplementing the geographical distribution modes of wetland soil microbial communities at small scale.