Effects Of Acid Mining Drainage On Microorganism And The Abundance Of Functional Genes Involving In C,N And S Transformation In Soil Profile

The earth is rich in mineral resources.One of the minerals is pyrite produces with the characteristics of low-pH,high-salt,high-heavy metal acid mine drainage(Acid Mine Drainage,AMD).Invade the soil through surface runoff and infiltration.Causing many troubles by discharge AMD into the surrounding environments and then given to the humans.Under this extreme environment,there are still some microbial populations that remain there and drive the biogeochemical cycle of carbon,nitrogen and sulfur in the soil profiles,and the functional genes that regulate microbial metabolism play an important role,such as nitrogen fixation gene nifH,ammonia oxidation gene amoA-AOA,amoA-AOB,denitrification gene nirS,nirK,nosZ,anammox gene HZO,methane oxidation genes pmoA,pmoA1,pmoA2,sulfur reduction gene aprA,dsrB,driving microorganisms metabolism and soil material circulation.Therefore,this experiment is based on the soil which are contaminated by acid mining drainage in Tongling City,Anhui Province.The soil samples are collected outdoors,through high-throughput sequencing technology,polyacrylamide gel electrophoresis,real-time fluorescence quantitative polymerase chain reaction and other molecules.Biotechnology,analysis of the characteristics of microbial and C,N,S(Carbon,Nitrigen and Sulfur)transformation functional gene abundance in soil environment contaminated by acid mining drainage,and temporal and spatial discussion of microbial diversity in soils involved in C,N,S metabolism in the study soil.The dynamic changes of sexual and functional gene abundance provide a theoretical basis for the treatment of farmland soil,contaminated by acid mining drainage.The main findings of this experiment are as follows:1.Compared with uncontaminated areas,the amount of microorganisms in soil contaminated by acid mining drainage is reduced,and there is a significant correlation between microbial quantity and physical and chemical properties.The 16S abundance copy number of bacteria and archaea per gram of dry soil was 3.01×1013-5.80×1013,4.30×1011-9.06×1011,respectively,and the bacterial content in soil was higher than that of archaea;in the contaminated and control soil profile,the number of bacteria in the surface soil of 0-20 cm was significantly higher than that of other layers(p<0.05).The number of bacteria and archaea decreased with the increase of profile depth,but the number of bacteria was decreased.The rate of decline is lower than bacteria.The contents of total nitrogen and nitrate nitrogen were positively correlated with the abundance of bacteria and archaea in soil.The abundance of bacteria and archaea was significantly negative correlated with the contents of heavy metals,such as iron,manganese,cobalt and nickel in soil,while the contents of heavy metals such as copper,cadmium and lead are extremely positively correlated;2.The microbial diversity in the soil environment contaminated by acid mining drainage is reduced.The physical and chemical properties of heavy metals such as pH,iron,chromium,lead,copper,zinc,nickel and manganese are closely related to the microbial population structure,among which S content is positively related with Shannon and Simpson index,while Fe2O3 is negatively correlated.The microbial diversity index Chaol index,Shannon index and Simpson index of soil in the contaminated area decreased,and the species richness of the surface soil(0-10cm)was relatively high.The proportion of soil actinomycetes in the contaminated area was higher than that of uncontaminated areas,about 10%higher;3.The functional gene abundance of C?N?S transformation in the soil of the acid mining drainage contaminated area and the control area decreased with the increase of the depth of the section,and the maximum depth was 0-10 cm.AMD has a significant eff-ect on the functional genes nifH,nirS,amoA-AOB and HZO,pmoA,dsrB in the soil profile.In the AMD-contaminated profile soil,amoA-AOA and nirK play a more important role in ammonia oxidation and denitrification.An important role,the pH reduction caused by AMD pollution and the increase in total sulfur and total iron content are the main reasons for the changes in ammonia oxidation and denitrification in the soil profile.;4.In contaminated soil,the amount of microbial biomass and the functional gene abundance involved in C?N?S transformation generally have a trend with the season,which is characterized by low summer and high autumn and winter.Comparing the abundances of the same functional genes under different conditions in July(summer),September(autumn),and December(winter),it can be seen that the functional genes involved in C?N?S transformation,the gene abundance of nifH,nosZ,amoA-AOB,HZO,pmoA,pmoA1,pmoA2,aprA and dsrB increased with time,while the abundance of functional gene nirS,involved in denitrification,was higher in summer.At the same time,it was also found that in the soils of summer,autumn and winter,the microbial biomass in the 0-20 cm profile depth and the functional gene abundance of C?N?S were relatively high.