Tubeworms

I am reading "Deep-Ocean Journeys" by Cindy Lee Van Dover. Cindy Lee Van Dover was the first female pilot of the human operated vehicle, Alvin. In her book, Cindy not only discusses her triumphs as a pilot, but the beauty of deep sea. She describes many of the organisms seen near hydrothermal vents. One organism that caught my attention the most was the hydrothermal vent tubeworm.

Tubeworms

Scientists hypothesized about continental drift, and found that plate tectonics move, causing the seafloor to spread and hydrothermal vents to form. New land is formed when magma pushes through the lithosphere, while old land is sucked into the subduction zone, where it turns into magma again. Harry Hess called this “geopoetry.” 

In order for a hydrothermal vent to exist there must be a source of energy. Since, hydrothermal vents are in the absence of the sun, organisms rely on heat, which is expelled from underwater volcanoes, for energy. Seawater and earthquakes are also present. Earthquakes cause the plates to shift, allowing magma to reach the surface, while the cold seawater cools the magma, forming sediments.

At the Rose Garden vent, tubeworms can be found that are six feet long. Tubeworms have crimson plumes and long white tubes. They usually colonize together in parallel lines. At the Venture hydrothermal field, tubeworms can get as tall as eight meters. There are so many tubeworms that the land beneath them goes unseen.

Tubeworms have good reflexes and disappear into their tubes when being attacked by hungry crabs. This makes it easier for Alvin to pick up the organism and bring the tubeworm back to the lab.

Once on deck, the tubeworm is pale and gray. The worm has a collar like ring muscle that helps it move, while the tube itself acts as armor. In adult tubeworms there is no mouth, digestive system, guts, or anus. Colleen Cavanaugh found that bacteria produce the nutrients needed for the tubeworm to survive. The bacteria use sulfide produced from the vents to perform chemosynthesis.

When scientists went back to the Rose Garden vent they found that the tubeworms had been replaces by Golden Brown Mussels. They believe that the tubeworm succumbed to the difference in nutrient conditions, allowing the mussels to flourish.

Mussels have a foot that allows them to climb. They go through the cycles of anchoring, bootstrapping, detaching, and reattaching, allowing mussels to move to different spots.

Clambake is a graveyard site where clams used to flourish. Shells are now left behind, and the meat has been eaten by crabs. Scientists think that this vent site could have shut off for one of two reasons. They believe that a vent site can die slowly as conduits choke with minerals or faster as earthquakes modify flow or catastrophes occur.