Here’s a question I bet you’ve never asked yourself: what gives mussels their, um, muscles? I never asked myself that question, either. But I read an interesting article recently about how mussels are able to “glue” themselves to rocks and things underwater. It all comes down to their “byssus,” and yes, “byssus” is the Word of the Day.
A “byssus” (rhymes with “kiss us”) is a bundle of filaments secreted by certain bivalve mollusks, like mussels, which are used to attach the mollusk to a rock, or the seabed, or just about any other thing that’s handy and not moving.
If you’ve ever cooked fresh mussels, you’ve had to remove the “beard” before cooking. That inedible beard is the byssus.
The byssus is made up of keratin – the same kind of protein that makes up hair, nails, horns, claws and hooves among us land animals – and “polyphenolic proteins,” which are a naturally occurring biological “glue.”
The stuff a byssus is made from is strong. Really strong. So strong that if you remove a mussel that has attached itself to a rock, you’re very likely to chip off some of the rock face in the process.
Scientists are really interested in how the byssus adhesive works, because unlike most adhesives, the “glue” of the byssus doesn’t degrade in water. Heck, even Spider-Man’s webs dissolve after about an hour! A team of chemical engineers in South Korea has been studying mussels and their byssus (byssuses? byssi?) to try to develop an equally strong and water-resistant adhesive.
There’s one other, lesser known use for the byssus. The “noble pen shell” or “fan mussel” (Pinna nobilis), a really large mussel native to the Mediterranean, secretes long filaments that can be harvested, spun and woven into a fabric that’s finer than silk, extremely light and warm. The popular name for it is “sea silk,” although in Chinese it’s sometimes called “mermaid silk.”
But before you rush out to flex your mussels and buy a sea silk scarf, you should know that the sea silk industry has almost disappeared, because Pinna nobilis has almost disappeared. A combination of pollution and over-fishing has left the species on the edge of extinction. Just further evidence that humans suck.
