Howdy. I’m that naked guy you’ve probably seen beachcombing. You can be sure it’s me by my potbelly, which makes it look like I’ve swallowed a basketball.
Because I carry my keys and phone in my hands, I need a place to carry any washed-up objects I wish to take home. I was inspired by the California mussel (Mytilus californianus) to simply glue stuff into my beard.
The California mussel is the large bivalve mollusk you see attached in masses to rocks that are exposed to surf in the high intertidal zone. The mussel beds form living reefs that provide shelter, attachment spots and feeding opportunities for many different creatures. The mussels attach themselves to the rocks and each other using byssal threads, which are also known as “mussel beards.”
Credit: Photo by Mike Kelly
The mussel uses the second-strongest known natural marine glue to stick the flexible brown threads to things. First, the mussel uses its muscular foot to find a good attachment point. Then, it releases a liquid protein mix into a groove in the foot, which acts like a mold for the thread. The mussel glues a splayed-out anchor point to the surface, and the other end remains attached to its foot. The thread turns solid when the mussel allows seawater to contact it.
Perhaps the most unique property of the glue is that it bonds to wet surfaces, unlike standard synthetic super glues. Inspired by the chemistry of mussel glue, scientists are developing adhesives that can be used to bond internal tissue during surgery. Oddly, the strongest natural marine glue belongs to the barnacles that commonly attach to mussels. These glues evolved in response to pounding waves, so you might thank the surf for saving your life one day.
Another amazing property of a single byssal thread is that it supposedly has the pulling strength of 10-pound-test fishing line, and each mussel may deploy dozens of threads. Plus, each filament contains a short elastic segment that acts as a built-in shock absorber.
We think of mussels as being stationary, but they can move around by using the threads as a sort of winch system. The foot can reach out to attach a thread to a spot and then pull itself along. It can then quickly release the thread from the foot and continue moving using additional threads.
Credit: Photo by Mike Kelly
Even with this amazing system, California mussels are often torn loose by big surf — sometimes in clusters. They may reattach if they land in a favorable spot, but most will end up dying very slowly on the beach. They might also end up falling into one of the giant green sea anemones that, not coincidentally, often reside right under mussel reefs. Ochre stars also creep up from that zone to feed on mussels at high tide.
So, California mussel shells are common finds on local beaches. They usually have a rough blue, purple or black outer surface with white patches, and attractive iridescent colors on the inside. The biggest washed-up mussel shell with both valves I’ve beachcombed so far was an 8.5-incher with a large barnacle attached. Unfortunately, I already had some driftwood, a dried starfish and a crab trap buoy glued to my beard.
I was forced to carry that mussel shell pinched between my buns, which caused lacerations that became infected by flesh-eating bacteria. The bacteria must have been hungry because they left me with nothing but a couple of large divots back there.
But now I’m even more recognizable! So, feel free to stop and say “howdy,” and please don’t be shy about offering to help me carry something.
Biologist Mike Kelly (he/him) is also the author of the book Tigerfish: Traditional and Sport Fishing on the Niger River, Mali, West Africa. It’s available at Amazon or everywhere e-books are sold.
This article appears in Xine:wh-ding.