Overview
Phragmatopoma californica, commonly known as the sandcastle worm, the honeycomb worm or the honeycomb tube worm, is a reef-forming marine polychaete worm belonging to the family Sabellarididae. It is dark brown in color with a crown of lavender tentacles and has a length of up to about . The worm inhabits the Californian coast, from Sonoma County to northern Baja California. Sandcastle worms live in colonies, building tube reefs somewhat similar to sandcastles (hence the name), which are often seen on rocky beaches at medium and low tide. The sandcastles, which have a honeycomb-like outward appearance, can cover an area of up to on a side. On rocky beaches, settlement is dependent on larval behavior in the water column and perception of chemical cues when the larvae contact the tubes.
Sandcastle worms should not be confused with the similar, but more northern Sabellaria cementarium which are found from Alaska to southern California and have an amber-colored operculum.
Underwater glue
In 2004, researchers from the University of California, Santa Barbara (UCSB) discovered that the glue used by the Phragmatopoma worm to build its protecting tube was made of specific proteins with opposite charges. Those proteins are called polyphenolic proteins that are used as bioadhesives. They succeeded in obtaining the sequence of these adhesive proteins. Inspired by these results University of Utah researchers reported in 2009 that they succeeded in duplicating the glue that the worms secrete and use to stick sand grains together underwater. The typical amount of glue that the worm produces at once is approximately 100 picoliters, requiring 50 million to fill a teaspoon.
If found to be practicable, the synthetic glue, which is based on complex coacervates, could be used to fix small bone fragments, instead of metal stabilizer devices such as pins and screws, which are challenging to use. The glue sets in about 30 seconds, probably triggered by the large difference in acidity between the acidic glue and seawater. Curing takes about six hours, as the proteins cross-link, reaching the consistency of shoe leather.
External links
* * * Photographs by Peter J. Bryant * University of Utah photographs of sandcastle worms and related materials research * University of Utah video of worm building tube