geothermobacterium ferrireducens geothermobacterium ferrireducens geothermobacterium ferrireducens is a species of hyperthermophilic thermodesulfobacterium discovered and known exclusively from obsidian pool in yellowstone national park, wyoming. its name comes from the latin ferrum, meaning iron, and reducens, meaning conversion to a different state. the bacteria are gram-negative rods, and move using a single flagellum. they live in high temperatures, between 65 and 100 °c, with 85 to 90 degrees being the optimum range- the highest optimum temperature range of any member of the phylum bacteria. they are roughly 0.5 µm by 1.1 µm. they have an unusual biology: they do not require organic carbon for growth, instead growing by coupling hydrogen oxidation with a form of fe(iii) oxide reduction. geothermobacterium ferrireducens scientific classification domain: bacteria phylum: thermodesulfobacteriota class: thermodesulfobacteria order: thermodesulfobacteriales family: thermodesulfobacteriaceae genus: geothermobacterium species: g. ferrireducens binomial name geothermobacterium ferrireducenskashefi et al. 2002