Hydrothermal Vent and Cold Seep Worms: Vestimentifera

Hydrothermal vent and cold seep worms have long, wormlike bodies reaching up to 9.8 feet (3 meters) in length. They live in whitish to gray-brown tubes at least as long as their bodies and are attached to hard surfaces on the ocean bottom. The tubes are made of chitin (KYE-tehn), a material similar to fingernails that makes up the external skeletons of insects, spiders, and their relatives. Most of the green to brown body remains inside the tube except featherlike structures, or plumes, and a pair of winglike flaps forming a collar that protects the head region. Special glands inside the flaps may produce the material used to make the tube. Bright red plumes surround the flaps. When threatened, the plumes are quickly withdrawn inside the tube. The plumes and blood vessels along the body are red because they are filled with blood containing a protein called hemoglobin (HE-meh-GLO-bihn). Hemoglobin captures oxygen from the water, helping these worms to breathe under water.

All hydrothermal vent and cold seep worms lack mouths or digestive tracts as adults. Like beard worms, they rely on the bacteria inside them for food. The body trunk is filled with reproductive organs. The segmented tail has a row of hooks that firmly anchor the body inside the tube.