tube worms (Riftia pachyptila)

Riftia pachyptila, commonly known as tube worms, are found near deep-sea hydrothermal vents. They can grow over 2 meters long and lack a digestive system. Instead, they have a specialized organ called a trophosome containing symbiotic bacteria that perform chemosynthesis—using chemicals like hydrogen sulfide from the vents to produce nutrients. The worms have a protective tube made of chitin that anchors them to the ocean floor. They rely entirely on their bacteria partners for nutrition, allowing them to thrive in extremely harsh, nutrient-rich environments where sunlight doesn't reach.