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Chemosynthetic bacteria

Chemosynthetic bacteria are chemolithotrophs that live under the extreme conditions of hydrothermal vents, thriving in temperatures that can reach up to 150°C, and with pressures reaching 250 Atmosphere.

They use sulfur compounds, such as hydrogen sulfide and elemental sulfur, produced by geological activity, as an energy source to create organic material, instead of using sunlight to generate energy. Chemosynthetic microorganisms help to support the biogeochemical cycle of sulfur. They form the base of the food chain in deep-sea ecosystems, sustaining diverse organisms such as tubeworms, clams, and shrimp with unique symbiotic and commensal relationships.

Tubeworms, for instance, which may grow to over 2 m, lack a mouth and gut but house billions of sulfur-oxidizing bacteria in their trophosome. Tubeworms transfer haemoglobin from their red plumes to the bacteria living inside their tissues, through the use of hydrogen sulfide, and in return, the sulfur-oxidizing bacteria facilitate the tubeworms in the absorption of carbon nutrients. 

Chemosynthetic bacteria - Sulfur-reducing and sulfur-oxidizing bacteria - live symbiotically, complementing and sustaining each other's respiration, and energy conservation in anaerobic conditions, and they form microbial mats with various colours, contributing to the vibrant hues seen on seamounts.

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