| The copper base of Zhongtiaoshan was one of the seven largest copper base of China which is located in Yuanqu County of Shanxi province and it was also our country's non-coal underground mining,copper reserves was 3 million t,it can mining 7 million t and ore dressing 7.2 million t per year.But mining activity can cause environmental damage and soil heavy metal pollution.The heavy metals contained can be enriched in plants,animals,and human body through the food chain,finally can endanger human health.Plant colonization can transfer,absorb and volatile heavy metals in the soil.As the most important and active part of soil ecological environment,microorganism can participate in global biogeochemical cycles,reducing heavy metal poisoning and improving soil quality and plant grouth.Microorganisms which exist in marginal and fragile ecological environment,are sensitive indicators of soil restoration.Dynamics of microbial community structure and diversity,it helps to understand the ecological recovery of soil in the mining area.Based on the results of high-throughput sequencing of bacterial 16 S rRNA V3 and fungal ITS1,the soil microbial community structure of three layers of copper tailings were analyzed;the spatial and temporal dynamics of soil bacterial community diversity in six restoration gradients were analyzed by deformation gradient gel electrophoresis(DGGE).We further analyzed the structural characteristics of soil microbial community and the mechanism of community construction in the process of tailings dam land restoration.Come to the following conclusion:(1)Dynamic characteristics of soil environmental factors in tailings damResearch of soil heavy metal contents of Cu,Pb,Cd and As overweight,Cr,Ni,and Zn were not overweight.Soil pH can change significantly with recovery time,the plots of 30 y,15y and 1y higher than the 45 y,40y and 5y sites.In different seasons,soil pH in April,higher than June,September and November.Soil nutrient content has changed markedly along the recovery time of the tailings dam.TC and TN in soils from 45 y and 40 y can significantly higher than 30 y and 15y?TC and TN in soils of 5y increased.Nutrient(TN and TC)in July and September are higher than November and April.TS can reach the highest content in September and November.(2)The dynamics of plant diversity in tailings damField investigation used to analysis of plant diversity by.Shannon index of plants changes with recovery time significantly,45 y and 40 y ployts was significantly higher than the 30 y,15y and 5y plots.The difference of Pielou indices between different films was not significant.Shannon and Simpson index in different quarters of plants did not change significantly.(3)The changes of soil quality in tailings damTailings dam of soil quality changing soil quality(soil enzyme activities and soil respiration)and soil nutrient content the same trend,with the succession of different restoration time.Urease and Invertase activity in soils were high in September and November.Catalase activity in November was the lowest.Soil respiration of 45 y,40y and 5y plots in September was the weakest,but at 30 y and 15 y plots April last.Soil quality is mainly affected by nutrients,plant diversity and impact of microbial community structure.Heavy metals(Mn,Pb,etc)inhibit the recovery of soil quality,but its effect is small.(4)The characteristics and influencing factors of microbial community structure in tailings damMicrobial community structure of tailings dam of 45 y,15y and 1y plots metagenomic sequencing using Illumina MiSeq platform,tailings dam advantages of different gradients of soil bacteria are Proteobacteria,and Firmicutes and Actinobacteria,Acidobacteria.Advantages of soil fungi are Ascomycota,Basidiomycota and Zygomycota.The results of non-metric measurement(NMDS)and mantel test showed that the changes of bacterial and fungal community structure affected by soil physicochemical properties,heavy metal contents,plant diversity and soil quality,and the interaction between soil bacterial community and fungal community was significant.The Sphingomonadaceae can tolerate heavy metal and can be used to predict the pollution level of heavy metal.(5)Temporal and spatial dynamics of bacterial community diversity in tailings damThe diversity of bacterial communities of tailings dam six recovery gradients in four seasons was analyzed by denaturing gradient gel electrophoresis.The Shannon and Richness indices of the bacterial community of the tailings dam were significantly related to the soil recovery time,and consistent with the soil nutrient content and soil quality.but Simpson index and Pielou index did not change with the recovery time.At the 45 y,30y and 15 y plots,the bacterial community diversity(Shannon and Richness indices)were significantly higher in July than November.RDA analysis results showed that bacterial community diversity(Shannon index,Richness index)is mainly influenced by soil nutrient content(TC and TN).Structural equation modeling(SEM)results show that in July,November and April,the physicochemical properties and soil quality have a greater effect on the diversity of soil bacterial communities,but the role of physicochemical properties and plant species diversity in bacterial diversity on even more in September. |
PDF Full Text Request