Sand Worms Clam Worms and Tubeworms: Polychaeta

Physical characteristics: The body of a tubeworm is pale yellow to red and has up to 200 segments. It measures up to 1.9 to 2.7 inches (50 to 70 millimeters) long. The head is crowned with numerous tentacles that spread out into circular, feathery fans when extended outside the tube. The head also has a pinkish white, funnel-shaped cover. The cover acts as a cork when the worm withdraws inside its tube. The hard tube is made of calcium carbonate and has a few irregular ridges.

Geographic range: Tubeworms live in the northeast Atlantic Ocean and the Mediterranean Sea.

Habitat: Tubeworms live in depths to 820 feet (250 meters). They live in hard tubes attached to hard surfaces, such as rocks, stones, Tubeworms are usually solitary in open waters, but in sheltered habitats dense populations of tubes, they may form small reefs. (Illustration by Amanda Humphrey. Reproduced by permission.) and bivalves. Bivalves are clams, mussels, oysters, and other aquatic animals with shells made up of two parts or halves.

Diet: They use their fanlike tentacles to create currents that draw in water carrying bits of floating food.

Behavior and reproduction: Tubeworms are usually solitary in open waters, but in sheltered habitats dense populations of tubes, they may form small reefs.

Every summer males and females release sperm and eggs into the water where fertilization takes place. The larvae reach adulthood in less than one year. Their entire life cycle takes anywhere from two to five years.

Tubeworms and people: The tubeworms' permanent tubes help to create habitats for other marine species.

Conservation status: Tubeworms are not considered endangered or threatened. ∎