Microbial helpers allow cyanobacteria to thrive in ferruginous waters.

The Great Oxidation Event (GOE) was a rapid accumulation of oxygen in the atmosphere as a result of the photosynthetic activity of cyanobacteria. This accumulation reflected the pervasiveness of O on the planet's surface, indicating that cyanobacteria had become ecologically successful in Archean oceans. Micromolar concentrations of Fe in Archean oceans would have reacted with hydrogen peroxide, a byproduct of oxygenic photosynthesis, to produce hydroxyl radicals, which cause cellular damage.

Metal Reduction and Protein Secretion Genes Required for Iodate Reduction by Shewanella oneidensis.

The metal-reducing gammaproteobacterium reduces iodate (IO) as an anaerobic terminal electron acceptor. Microbial IO electron transport pathways are postulated to terminate with nitrate (NO) reductase, which reduces IO as an alternative electron acceptor. Recent studies with , however, have demonstrated that NO reductase is not involved in IO reduction.