FeII + CO2 → [Leptospirillum] → FeIII + organic carbon (or S + CO2 → [Thiobacillus] → SO42− + organic carbon)	(1)
Organic carbon + SO42− → [Thermodesulfofibrio]→ CO2 + S2−,
with as feeding reaction CH4 + O2 → [Methanotrophs (e.g., Methylococcales, Methylococcaceae)] → organic carbon + CO2