How do organisms survive at hydrothermal vents without light?

Organisms at deep-sea hydrothermal vents survive through chemosynthesis, a process where microbes use dissolved chemicals like hydrogen sulfide from vent fluids to fix carbon and produce sugars. Chemolithoautotrophic bacteria and archaea form the base of the food chain, supporting diverse dependent animals such as giant tube worms, clams, and shrimp. This chemical-driven ecosystem replaces photosynthesis entirely due to the total absence of sunlight in the deep ocean.

What we know

• Hydrogen sulfide chemosynthesis is predominant over photosynthesis at hydrothermal vents because there is a lack of light in these deep environments. [2]
• Giant tube worms host bacteria in their trophosome that use hydrogen sulfide as an energy source and electron donor to fix carbon dioxide into sugars and amino acids. [2]
• Chemosynthetic bacteria and archaea form the base of the hydrothermal vent food chain, supporting complex communities of clams, limpets, and shrimp. [3, 5]
• Hydrothermal vents form when seawater enters oceanic crust, is heated by magma, accumulates dissolved minerals and chemicals, and discharges back out into the ocean. [5]

Where to go next

• a case in pointWhat are black smokers and white smokers?
• how it workedHow do giant tube worms use symbiotic bacteria?
• what caused itWhat creates deep-sea hydrothermal vent fluids?
• the bigger pictureWhat other ecosystems exist in the deep sea?
• an unexpected connectionCould hydrothermal vents exist on outer space moons?

Sources

• [1]hydrogen sulfide chemosynthesis (Wikidata Q113101008) · CC0 1.0
• [2]Hydrogen sulfide chemosynthesis · CC BY-SA 4.0
• [3]Hydrothermal vent · CC BY-SA 4.0
• [4]Deep-sea community · CC BY-SA 4.0
• [5]Hydrothermal vent microbial communities · CC BY-SA 4.0