Analysis Of Microbial Community Structure And Function In The Adjacent Seawater Of The Arctic Yellow River Station

The study of microbial diversity and community had great significance for learning Arctic seawater ecosystem.The study was sampled at nine different sites in surface seawater of Svalbard Sea Water in Arctic.This article studied the abundance,morphological characteristics and diversity of cultivable planktonic bacteria in surface seawater from the Arctic Ocean by fluorescence enumeration,dilution culture techniques,physiological test and 16S rDNA gene identification method.Sampling from five sites,we used high-throughput approaches based on 16S rDNA genes to investigate the diversity and abundance from bacteria and archaea,and also used PICRUSt analysis to determine the functional sequence copies in surface seawater.We used high-throughput approaches based on the internal transcribed spacer?ITS?regions to investigate the diversity and abundance of fungi from the five sites,and also used FUNGuild to determine the fungal functional groups?guilds?in surface seawater.The cultivable planktonic bacteria results showed:?1?The average number of bacteria from BJ1-BJ9 was 2.88×10⁸cells·L^-1;?2?AB08,AB09 and AB17 strains were gram positive strains;?3?The marine cultivable bacteria was mainly composed by Actinobacteria,Flavobacteriia and Gammaproteobacteria,among which Pseudomonas was dominant?71%?.Bacterial community and structure indicated that Proteobacteria was the dominant taxon in all samples,followed by Bacteroidetes,Actinobacteria,Planctomycetes,Verrucomicrobia,Cyanobacteria,Chloroflexi,HKB19,Acidobacteria,Firmicutes and Armatimonadetes.Alpha and Gamma Proteobacteria was the dominant taxon within Proteobacteria.In site BJ7,Betaproteobacteria and Gammaproteobacteria were more than other kinds of Proteobacteria.Crenarchaeota was the most abundant phyla in archaea.Functional prediction showed that the copy reads of functional genes about carbon cycling had the most abundance,with methane metabolism dominant;while the least reads appeared in phosphonate and phosphinate metabolism.We got 240,786 qualified reads and1928 operational taxonomic units?OTUs?totally.Only 514 OTUs were assigned as fungi.Fungal communities and structures indicated that Ascomycota?44.36%?was the dominant phylum in all samples,followed by Basidiomycota?17.86%?and Zygomycota?0.05%?.Saccharomycetes was the dominant class within Ascomycota and Microbotryomycetes dominated within Basidiomycota.Most sequences were classified as facultative marine fungi after matching in NCBI database.Functional groups showed that saprotrophs was the most common assigned trophic mode,with the guild of undefined saprotrophs dominant.A large proportion guilds were unassigned or multiple.The Arctic is a unique sea area with abundant microbial resources.The marine microorganisms have special physiological and biochemical characteristics and environmental adaptation mechanisms,with important research significance.This study analyzed the microbial community structure and function of the sea area and laid an important foundation for microbial ecology research in the area.