The Influence Of Seasonal Variation On The Microbial Community Of Mohe River Silt And Water Environment

Microorganisms are widely distributed in our living environment and even in extreme environments.The complex natural conditions formed by seasonal changes will directly affect the structure and functional characteristics of microbial communities.Taking the surface water and silt of North pole village and Luoguhe village,Mohe county,Heilongjiang province,as the research objects,and using the traditional microbial culture observation method and the molecular biology technology of metagenomic sequencing,the following results were obtained through multivariate statistical analysis:In the microbial community structure under the environment of silt and water,a total of 103 phyla,186 classes,347 orders,645 families,2075 genera were obtained.And the majority was subordinate to the bacteria.At the level of phylum,Proteobacteria and Bacteroidetes,etc.were the main groups of microorganisms.At the level of class,Alphaproteobacteria,Betaproteobacteria,etc.were the main taxa.And Burkholderiales,etc.were the main taxa at the level of order.At the level of family,Caulobacteraceae,Comamonadaceae,Flavobacteriaceae,Intrasporangiaceae were abundant in each sample in different seasons.At the level of genus,Brevundimonas,Caulobacter,Flavobacierium,Polaromonas,Arthrobacter,Limnohabitans were the genus with the highest abundance in various samples in different seasons.In the COG functional annotation,the functional diversity of microbial communities in silt samples was spring and autumn>summer,and that in watery samples was summer>spring and autumn.In KEGG functional annotation,KEGG of the silt microbial community functional diversity was shown as:spring>summer and autumn,KEGG function of the watery microbial community diversity was:autumn>spring and summer,the advantage pathways of silt microbial community distribution in three seasons was:spring,autumn>summer,the advantage pathways of watery microbial community in three seasons was:summer>spring,autumn;In CAZy functional annotation,at the classification level,the silt microbial community carbohydrates active enzyme gene number was shown as:spring>summer,autumn,watery microbial community carbohydrates active enzyme gene number was shown as:autumn>spring,summer.At enzyme family level,most of the active carbohydrate enzymes in the silt microbial community showed:spring,autumn>summer,and the watery microbial community showed:summer>spring,autumn.In addition,KEGG functional diversity and carbohydrate active enzyme gene diversity in silt microbial community were lower than those in watery samples.Through the observation of culturable microorganisms and the comprehensive analysis of metagenome,with the change of seasons,the diversity of microbial community structure and function in silt was extremely rich in cold spring,but decreased significantly in hot summer.The overall performance of the structural and functional diversity of the watery samples microbial community was not very rich in spring,relatively rich in summer,and continued to be more abundant or slightly decreased in autumn.In addition,the diversity of gene,structure and function of the microbial community in silt was lower than that in water samples.There were also many differences in microbial community structure and function between the two environments.Anyhow,changes with the seasons change,there are a large number of cold-resistant or heat-resistant microorganisms and their functional genes to cope with seasonal changes,then the microbial functional gene with the seasons change corresponding rise and fall.Furthermore,it also indicates that seasonal change may be the main reason for the structural diversity and functional diversity of microbial community in the two environments.