Fine-scale spatial diversity of iron-oxidizing communities at the Lō’ihi Seamount. Lo'ihi Seamount bacterial communities

Chemolithoautotrophic iron-oxidizing bacteria play an essential role in the global iron cycle. Thus far, the majority of marine iron-oxidizing bacteria have been identified as Zetaproteo-bacteria, a novel class within the phylum Proteobacteria. Marine iron-oxidizing microbial communities have been found associated with volcanically active seamounts, crustal spread-ing centers, and coastal waters. From March-April 2013, samples were collected from rust-colored mats at various sites withing the Lo'ihi Seamount using the ROV Jason II. The goal of these efforts was to determine the diversity iron-oxidizing Zetaproteobacteria. Small, diffuse flow venting areas with high iron(II) concentrations and rust-colored microbial mats were observed at all sites . A novel, syringe-based precision sampler was used to collect discrete microbial iron mat samples at the three sites. The diversity of Zetaproteobacteria was assessed using a combination of 16S rRNA pyrosequencing. Sequencing analysis suggests that these iron mats contain cosmopolitan representatives of Zetaproteobacteria, but also exhibit diversity that may be uncommon at other iron-rich marine sites studied to date. This work adds to the growing understanding of Zetaproteobacteria ecology and suggests that this organism is likely locally restricted to iron-rich marine environments but may exhibit wide-scale geographic distribution, further underscoring the importance of Zetaproteobacteria in global iron cycling.