Figure 6
From: The possible occurrence of iron-dependent anaerobic methane oxidation in an Archean Ocean analogue
Potential role of iron-oxide AOM in Archean Ocean metabolism. In the Archean Ocean, anaerobic metabolism (photoferrotrophy, methanogenesis and CO-acetogenesis in dark blue) dominated before the advent of oxygenic photosynthesis (in light blue). In red, we propose anaerobic methane oxidation (AOM) using Fe oxides as electron acceptor as additional metabolic process. Before the advent of oxygenic photosynthesis, Fe3+ dependent AOM linked photoferrotrophy and H2-methanogenesis that so far have been seen as two parallel and unconnected processes. After the advent of oxygenic photosynthesis, Fe oxides-dependent AOM might have used the abundantly produced Fe(OH)3 from the oxidation of Fe2+ by O2 to further remove CH4 from the water column, facilitating the increase of O2 in the atmosphere and the great oxidation event.
