Structural Analysis On Microbial Community In Antarctic And Arctic Nearshore Soil

Soil microorganisms in the northern and southern polar regions is an importantpart of the polar nearshore ecosystems, and the microbial community structure canreflect the effect of changes in soil physical and chemical factors and evenenvironment.In this paper，soil samples were collected from Fildes Peninsula of KingGeorge Island during Chinese29th Antarctic scientific expedition and fromNy-Alesund area during Chinese2012Arctic Yellow River Station scientificexpedition.131Antarctic bacteria,28Arctic fungi and69Arctic bacteria wereobtained by coating the plate and crossed separation method. After16s and ITSsequencing and comparison of the purified strains, phylogenetic analysis of bacterialsystem was conducted and phylogenetic tree was built by neighbor-joining methodwith Mega6.0software. According to the taxonomy, the community characteristicsand preponderant flora were summarized. It was found that in the northern andsouthern nearshore soil, bacterial community composition was similar, among whichPseudomonas accounted for the greatest number, followed by Arthrobacter andFlavobacterium; while Geomyces and Mortierella were the dominant flora in Arcticsoil.According to different environmental characteristics of the north and south poles，eight soil samples in typical stations were chosen to conduct454high-throughputsequencing， and diversity composition data of the entire bacterial communityincluding uncultured microorganisms was obtained.The differences and similaritiesbetween stations were analyzed by the method of OUT cluster analysis，thermal-typecomposition profiles, network pie chart， etc.Combined with soil physical andchemical factors,the main component analysis diagram were made to reveal the mostimportant factor affecting soil microbial community composition.The results showed that in Antarctica，district of human life was most affectedby organic matter and nutrients；district of seal was significantly affected by portland；and district of penguin was obviously affected by PH value.While in the Arctic，microbial communities preferred rich nutrition in Polygonaceae soil， soilcommunities of hair grass roots was greatly influenced by portland， andmicroorganism in Arctic willow roots soil preferred the organic-poor environment.The physical and chemical factors were coupled with the activities andmetabolism of humans, seals, penguins and different plant， and reflected thatbacterial community composition can be changed regularly by the environmental impact of external events.This experiment has brought the rich enlightenment toresearchers that microscopic analysis of changes in bacterial communities caneffectively reflect the changes in the external environment，and forecast will bringdirectional change in microbial communities and the whole ecosystem.