Vestimentiferan tubeworms, unique deep-sea dwellers lacking a digestive system, rely on a symbiotic partnership with sulfide-oxidizing endosymbiotic bacteria (endosymbionts) for nutrients. Living in chemosynthetic ecosystems like hydrothermal vents and cold-seeps, these worms house the endosymbionts in a specialized organ, facilitating gas exchange to fuel the microbes' organic matter production, leading to the tubeworms' remarkable growth and dense communities.