How does Riftia pachyptila survive without a digestive system?

The giant tubeworm Riftia pachyptila lives in deep-sea hydrothermal vent environments and lacks a digestive system entirely. Instead, it relies on a symbiotic relationship with chemotrophic sulfur-oxidising bacteria housed inside a specialized organ called the trophosome. These bacteria use chemicals like hydrogen sulfide from the vents to perform chemosynthesis, providing energy and food for the host worm.

What we know

• Adult Riftia pachyptila worms lack a digestive system entirely. [2]
• Riftia pachyptila depends on symbiotic chemotrophic sulfur-oxidising bacteria for energy. [2]
• Symbiotic bacteria that feed the host are housed in a highly vascularised organ called the trophosome. [3]
• The hydrothermal vent habitat provides hydrogen sulfide utilised by the tube worm for bacterial chemosynthesis. [2]

Where to go next

• how it workedWhat is a trophosome?
• what caused itHow do hydrothermal vents support deep-sea ecosystems?
• the bigger pictureWhat are Siboglinidae tube worms?
• a case in pointWhich other organisms depend on chemosynthesis?
• whoWho studies extreme environment symbioses like Peter Girguis?
• an unexpected connectionCan hydrothermal vents exist beyond Earth?Active hydrothermal vents similar to those supporting giant tubeworm symbioses are thought to exist on Jupiter's moon Europa and Saturn's moon Enceladus.

Sources

• [1]Riftia (Wikidata Q15240740) · CC0 1.0
• [2]Riftia · CC BY-SA 4.0
• [3]Trophosome · CC BY-SA 4.0
• [4]Hydrothermal vent · CC BY-SA 4.0
• [5]Peter Girguis · CC BY-SA 4.0