Bacterial community of sediments from the Australian-Antarctic Ridge

Abstract

Benthic bacterial communities in the ocean environment play significant roles in the biogeochemical cycle and remineralization of organic matters. In this study, the bacterial community of surface sediments from Australian-Antarctic Ridge (AAR) was revealed by 454 pyrosequencing method. Bacterial communities inhabiting the sediments of AAR were highly diverse, covering 39 different taxonomic groups at the phylum level. Among 39 phyla and candidate phyla, Gammaproteobacteria, Planctomycetes, Actinobacteria, Deltaproteobacteria, Acidobacteria, Alphaproteobacteria, Chloroflexi, Bacteroidetes, Chlorobi, and Gemmatimonadetes were dominant comprising approximately 85~88% of bacterial community. 16S rDNA sequences of major OTUs with 1% or higher abundance showed high similarity (96.6% ~ 100%) with uncultured environmental sequences which were mostly recovered from sediments of various areas of Arctic Ocean, Southern Ocean, Atlantic Ocean, Indian Ocean, Pacific Ocean, etc, which implies that they represent taxonomically novel groups of bacteria and their function and physiology are mostly unknown and marine sediments were the most important source of the major OTUs.ge (AAR) was revealed by 454 pyrosequencing method. Bacterial communities inhabiting the sediments of AAR were highly diverse, covering 39 different taxonomic groups at the phylum level. Among 39 phyla and candidate phyla, Gammaproteobacteria, Planctomycetes, Actinobacteria, Deltaproteobacteria, Acidobacteria, Alphaproteobacteria, Chloroflexi, Bacteroidetes, Chlorobi, and Gemmatimonadetes were dominant comprising approximately 85~88% of bacterial community. 16S rDNA sequences of major OTUs with 1% or higher abundance showed high similarity (96.6% ~ 100%) with uncultured environmental sequences which were mostly recovered from sediments of various areas of Arctic Ocean, Southern Ocean, Atlantic Ocean, Indian Ocean, Pacific Ocean, etc, which implies that they represent taxono