Bacterial Community Composition and Diversity in Methane Charged Sediments Revealed by Multitag Pyrosequencing

Bacterial diversity in sediments obtained along the Chilean margin from areas containing methane seeps, and a hydrate mound were explored by cloning and sequencing and multitag pyrosequencing (MTPS). These libraries were statistically compared to determine the robustness of taxonomic assignment derived from multiplexed pyrosequencing strategies targeting variable regions V1 and V2 of the small subunit rRNA gene for environmental studies. There was no statistical difference in the composition of the libraries, thus, MTPS was utilized to describe diversity in three geochemical zones in these environments. Unidentified Cyanobacteria isolates were abundant in the sulfate reduction zone (SRZ), Deltaproteobacteria were concentrated at the sulfate methane transition zone (SMTZ) and Chloroflexi/GNS dominated methanogenesis zone (MGZ). Although there was variation among specific groups, communities in the SRZ and MGZ did not differ significantly. However, the community dominated by Deltaproteobacteria differentiates the SMTZ from the other zones. Supplemental materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the free supplemental file.