울릉분지 심해지역에서 크기에 따른 미생물 군집구조 분석

Abstract

The size of microorganisms varies considerably. At the smallest end of this size spectrum are the ultramicrobacteria(UMB) which has a cell volume of less than 0.1μm3, irrespective of growth conditions. UMB are highly abundant in marine environments and they play important roles in the global nutrient cycle and in the marine food chains. In the present study the microbial diversity in the bathypelagic layer of Ulleung-basin was compared by the size fraction which is lager than 0.2μm(non-UMB) or smaller than 0.2μm(UMB). A total 420 clones of archaeal group and 303 clones of bacterial group were analyzed by 16S rRNA gene target sequence. All archaeal clones belong to Crenarchaeota and Euryarchaeota and a majority of both fractions was affiliated with Crenarchaeota marine group І by 82-85%. Bacterial clones were derived from 5 major lineages, α-,β-,γ- and δ-Proteobacteria and Chloroflexales. γ-Proteobacteria represents a dominant bacterial group in the fraction of non-UMB and UMB by 85% and 78%, respectively. Most clone of UMB is grouped into the uncultured group and these results support UMB possess high frequency of unique microbial community compared to non-UMB. [Supported by MEGRC]