Microbial Diversity And Metagenomic Analysis Of Soil In Melting Lake Area Of Arctic

In this study,12 soil samples were collected from 4 sites in the area where snow melted into lakes in the Ny-?lesund region of the Arctic Svalbard,and the soil samples collected were subjected to bacterial and fungal isolation,purification,morphological observation and count of colony,phylogenetic identification of 16S and18S rRNA genes and strain preservation.Meanwhile,universal primers were used to perform high-throughput sequencing of 16S rRNA V3-V4 and 18S rRNA V4 amplicon of the soil total DNA,and the metagenomic sequencing of soils samples were analyzed with the microbial diversity and functional diversity.In addition,the relationship between soil microbial diversity and environmental factors was analyzed based on soil physical and chemical properties.The results showed that 22 cultivable bacteria strains and 3 fungi strains were isolated and identified from 12 soil samples of 4 stations.Among them,22 strains belonged to Proteobacteria,Actinobacteria,Acidobacteria,and the dominant genera were the Masseria and Pseudomonas.3 strains of fungi belong ed to Ascomycota.The results of High-throughput sequencing showed that there were rich in bacteria and eukaryotes in the soil samples.In which the Shannon index of bacteria was 7.15-9.6,and the Shannon index of eukaryotes was 3.69-6.07.The most abundant bacteria were Proteobacteria,Acidobacteria and Actinobacteria;the most abundant fungus was Ascomycota.The results of metagenomic sequencing showed that the microbial communities in this area were mainly bacteria（90.5%）,and followed by archaea（1.2%）.Functional genes in soil samples were mainly related to Metabolism（17.1%）,genetic information processing（4.5%）and environmental information processing（3.7%）.Combined with the results of physical and chemical properties of soil,the correlation analysis of the microbial communities revealed that there was a strong correlation between the microbial community structure and soil physical and chemical properties in the melt-water lake area of Ny-?lesund region.Among them,pH and NO₂^--N had a higher correlation with soil bacterial communities,while NO₂^--N,water content,and organic carbon had a greater impact on soil eukaryotes.In addition,there had a big difference between the microbial community and gene function in sediment and soil samples of melt-water lake area.These results above indicate that melting of ice and snow can significantly change the diversity and function of soil microbes,and could further affect the terrestrial ecosystem.