The adult worm is an inch or so long, and an eighth-inch in diameter. But they build tubes several inches long, using sand grains and shell fragments.
"They will not leave their tube. They live in their tube and have dozens of tentacles they stick out one end of the tube, which is how they gather food and particles to build their shells with."
Tiny, hair-like cilia brush the sand grains and shell pieces down the tentacles so they can be grabbed by the worm's fleshy, pincer-like "building organ" and glued onto the under-construction tube piece by piece.
The worm "secretes two little dabs of glue onto the particle," says Stewart. "And the building organ puts it onto the end of the tube and holds it there for about 25 seconds, wiggling it a little to see if the glue is set, and then it lets go. The glue is designed to set up and harden within 30 seconds after the worm secretes it."
Worms build their tube-like shells next to each other, like stacks of pipes, to form a large colony. "One grain of sand at a time it builds big, reef-like colonies the size of Volkswagens," Stewart says. "A colony looks like a mound."
In the lab, Stewart previously showed the worms will use any handy building material, using their natural adhesive to build tubes by gluing together tiny pieces of egg shell, glass beads, red sand, bone, zirconium oxide, and even pieces of a silicon chip.
The Chemistry of Glue
Scientists already knew sandcastle worm glue contained proteins and a substance named dopa, which also is present in glue mussels used to glom onto rocks and boats.
"But we took the compositional characterization a lot further," hypothesized how the worm glue works, and used that to create the synthetic glue, says Stewart.
The sea worm's glue is made from two p
|Contact: Lee Siegel|
University of Utah