Iron-oxidizing microbial mats metagenomic assembly. microbial mat metagenome

Zetaproteobacteria are found throughout the marine environment at sites high in dissolved reduced iron. Analysis of microbial mats at two sites, a hydrothermal vent system (Lō'ihi Seamount, HI) and a tufa-depositing artesian spring (Soda Bay, AK) show a high abundance of Zetaproteobacteria by qPCR. T-RFLP fingerprint analysis of SSU rRNA genes showed these two sites to have overlapping yet distinctly different microbial communities. However, at both sites Zetaproteobacteria were the most abundant bacterial class as estimated by the metagenomic reconstruction of SSU rRNA genes. Functional metagenomic analysis showed RubisCO type II to be highly represented at both sites and most similar to those found in Zetaproteobacteria. These microbial mats are supported primarily by the chemoautotrophic activity of Zetaproteobacteria, which in turn are fueled by the oxidation of iron, though genes for photosynthesis were detected in the Soda Bay microbial mat. These results indicate that Zetaproteobacteria are functioning as ecosystem engineers within both of these iron-rich habitats.