Lamellibrachia

Lamellibrachia is a genus of tube worms related to the giant tube worm, Riftia pachyptila. It lives at deep-sea cold seeps where hydrocarbons (oil and methane) are leaking out of the seafloor. It is entirely reliant on internal, sulfide-oxidizing bacterial symbionts for its nutrition. L. luymesi provides the bacteria with hydrogen sulfide and oxygen by taking them up from the environment and binding them to a specialized hemoglobin molecule. Unlike the tube worms that live at hydrothermal vents, Lamellibrachia uses a posterior extension of its body called the root to take up hydrogen sulfide from the seep sediments. Lamellibrachia may also help fuel the generation of sulfide by excreting sulfate through their roots into the sediments below the aggregations. The most well-known seeps where L. luymesi lives are in the northern Gulf of Mexico from 500 to 800 m depth. This tube worm can reach lengths of over 3 m (10 ft), and grows very slowly, with individuals living to be over 250 years old. It forms biogenic habitat by creating large aggregations of hundreds to thousands of individuals. Living in these aggregations are over a hundred different species of animals, many of which are found only at these depths. While most species of vestimentiferan tubeworms live in deep waters below the photic zone, Lamellibrachia satsuma was discovered in Kagoshima Bay, Kagoshima at a depth of only 82 m, the shallowest depth record for a vestimentiferan.