After writing last week about keeping tenacious marine life from fouling boat bottoms, I thought I’d follow up with a description of just how these intertidal oddities stick so well to things and the innovations they inspire.
Let’s start with marine snails. One of my favorites is the smooth periwinkle — that tiny yellow snail that often disguises itself as a float on a piece of rockweed, one of our ubiquitous coastal seaweeds.
It is part of a group of molluscs (soft-bodied relatives of octopus and squid) called gastropods, which literally means “stomach foot.” Most of this tiny snail’s body is composed of a muscular foot that also contains a stomach so that it can creep along rocks while licking algae off of them with a sandpapery tongue of sorts called a radula. The other function of its foot is to act like a super suction cup, creating a vacuum seal of sorts between its shell and whatever it is sticking to.
The smooth periwinkle’s more common relative is the common periwinkle, which is generally a bit larger and brown in color. It is more often found on rocks than on seaweed and is known to come out of its shell in response to the vibrations of a humming human.
Its slightly larger fellow gastropod is the whelk. If you’ve found a shell on the beach with a perfectly drilled hole in it, you’ve seen the work of this carnivorous snail. It has a specialized proboscis that bores a hole into its prey and surreptitiously sucks it out from the inside.
All of these gastropods have an amazing ability to stay stuck despite the forces of the waves that regularly threaten to dislodge them. Their sticking power is so impressive that I had a marine biology professor when I was a student at Bowdoin who specialized in the biomechanics of marine snails — how their design keep them stuck despite the forces that push and pull them in many directions. Scientists have even designed custom-built apparatuses to measure the force of their suction in an attempt to figure out how they do this so well.
Biomechanics is fascinating, but one of my favorite subjects is biomimicry. This is the study of how we might “mimic” ways in which nature has solved a particular challenge. Imagine what you could do with a snail-force suction cup.
Biomimicry expert Janine Benyus wrote a terrific book about this (“Biomimicry: Innovation Inspired by Nature”) in which several of the prime examples are intertidal marine species.
The first lives inside those strange crusty little white volcanoes that cut unsuspecting bare feet exploring the rocks — the barnacle. These are odd creatures that cement their heads to rocks and eat with feathery feet that wave around outside the mouth of those little volcanoes. They are crustaceans, which means they are closely related to lobsters and crabs with whom they share jointed appendages and hard outer shells.
But, aside from having odd eating habits, the barnacle’s other superpower of sorts is their ability to produce marine cement that is stronger and more durable than anything humans have ever formulated. While people have understood that there are two components to most adhesives, it is only recently that scientists discovered that barnacles release an oily droplet to smooth the surface in preparation for a protein-rich adhesive. This is a major challenge for marine adhesives that attempt to stick to a variety of surfaces underwater. Nature has already found the solution — now we just have to figure out how to copy it.
The second creature is one you may have enjoyed steamed with white wine and garlic and is found in clumps in crevices on the rocks. These are blue mussels, one of Maine’s many delicious bivalves.
Unlike clams that live buried in the mud or scallops that live on the seafloor, squirting their way from place to place, mussels need to be attached to something. You may have discovered this if you’ve tried to pry them from the rocks.
When my husband was in the Navy, there were mussels galore growing on the “dabs” around one of the ships. I was part of a crew of snorkelers and divers that used paint scrapers to remove them (and lucky enough to put them into a floating cooler to take home and eat).
Mussels stick to things with an array of byssal threads — tiny fibrous anchors comprised of proteins and metals that combine elasticity and strength in a way that our best marine ropes cannot. Byssal threads have a flexible internal structure surrounded by and iron-laded coating that keeps them from breaking even under the highest of wave stresses.
These natural designs are truly remarkable and humbling. So, next time you’re on the seashore, take a moment to appreciate these amazing designs and let them inspire you.
Susan Olcott lives in Brunswick, with her husband and 7-year-old twin girls. She earned her M.S. in zoology studying the lobster fishery in New England. She then designed education programs for the Scripps Institute of Oceanography and taught biology to military personnel in Sardinia, Italy before returning to Maine to work on ocean planning for The Ocean Conservancy. She is now a freelance writer and currently writes about coastal issues for the Harpswell Anchor and The Working Waterfront and about local foods for the Brunswick Topsham Land Trust and Zest Magazine. In addition, she helps local schools pursue educational grants and writes children’s book reviews for the Horn Book’s family reading blog as well as for her own blog: susanolcott.wordpress.com.
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