bio

Chemolithoautotroph

A bacterium or archaeon that builds organic matter from CO₂ without a single photon, drawing its energy from oxidising reduced inorganic compounds: hydrogen sulfide, methane, molecular hydrogen or ferrous iron. Sulfide oxidation alone releases nearly 800 kJ/mol, enough to run the Calvin or rTCA cycle and support a complete primary-production economy. This is the foundation of hydrothermal vent ecosystems — where *Riftia* tubeworms have no gut at all and simply farm symbionts in an internal organ — and the reason the 1977 Galápagos Rift discovery rewrote where biologists thought life could be.