Chemosynthesis

Chemosynthesis is the biological process by which organisms build organic matter from carbon dioxide or methane and other nutrients using energy drawn from the oxidation of inorganic compounds such as hydrogen gas, hydrogen sulfide, or ferrous iron, rather than from sunlight as in photosynthesis. The chemoautotrophic organisms that carry it out are phylogenetically diverse, including sulfur oxidizing Gammaproteobacteria, Campylobacterota, Aquificota, methanogenic archaea, and neutrophilic iron oxidizing bacteria. In the dark ocean, chemosynthetic microorganisms typically derive energy by oxidizing hydrogen sulfide or ammonia, with or without oxygen, and they support dense animal communities at hydrothermal vents, methane clathrates, cold seeps, whale falls, and some isolated cave systems through symbiotic relationships. Scientists have proposed that anaerobic chemosynthesis could sustain life beneath the surfaces of Mars, Europa, and other bodies, and that chemosynthesis may have been Earth earliest metabolic pathway, predating both cellular respiration and photosynthesis. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/