The Fe(II)-Oxidizing Zetaproteobacteria: Historical, Ecological and Genomic Perspectives
Journal Article - Open Access
University of Delaware Lewes United States
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The Zetaproteobacteria are a class of bacteria typically associated with marine FeII-oxidizing environments. First discovered in the hydrothermal vents at Loihi Seamount, Hawaii, they have become model organisms for marine microbial FeIIoxidation. In addition to deep sea and shallow hydrothermal vents, Zetaproteobacteria are found in coastal sediments, other marine subsurface environments, steel corrosion biofilms and saline terrestrial springs. Isolates from a range of environments all grow by autotrophic FeII oxidation. Their success lies partly in their microaerophily, which enables themto compete with abiotic FeII oxidation at FeII-rich oxicanoxic transition zones. To determine the known diversity of the Zetaproteobacteria, we have used 16S rRNA gene sequences to define 59 operational taxonomic units OTUs, at 97similarity. While some Zetaproteobacteria taxa appear to be cosmopolitan, others are enriched by specific habitats. OTU networks show that certain Zetaproteobacteria co-exist, sharing compatible niches. These niches may correspond with adaptations to O2, H2 and nitrate availability, based on genomic analyses of metabolic potential. Also, a putative FeIIoxidation gene has been found in diverse Zetaproteobacteria taxa, suggesting that the Zetaproteobacteria evolved as FeIIoxidation specialists. In all, studies suggest that Zetaproteobacteria are widespread, and therefore may have a broad influence on marine and saline terrestrial Fe cycling.
- Biological Oceanography