Crunchies

The sandstone shore around the glacial erratic I visited last week, exposed at mid-tide, is densely populated by large barnacles. Millions of them; billions, maybe.

Thatched acorn barnacles*; one small patch.

I felt guilty, walking across this beach: crunch, crunch: at every step I could hear breaking shells. I tried to find spots with no barnacles to put my feet down, but there were few.

At one point, I turned and examined the barnacle I had just stepped on. There it stood, undisturbed, solid as ever. How strong are those shells? I think, possibly, the crunches I heard were dead, empty shells; they seem easy to break, from the right angle. More experiments are needed.

Stone formation, with barnacles, oysters, gull and more.

Farther down the beach, below the erratic, a few slabs of stone stood like a fence against the waves. Here, I found more barnacles, and a scattering of oysters, each one firmly cemented to the rock. The dark green stuff is rockweed.

More than meets the eye.

All across this plain, and crammed into every niche in the rocks, tiny critters go about their business, dwarfed by the barnacles. Looking closely, I found hundreds of pinhead snails. (But when I brought a handful home, most of them contained miniature orange-legged hermit crabs.) In the photo above, only one hermit crab is identifiable, but most of the blue-black snails are probably hermits, too. In the lower third, left of centre, a yellow patch is made up of whelk egg cases. And here and there, limpets try to blend into the rock.

Empty barnacle shell and black rock algae.

I brought home a few barnacles to clean my tank and feed my barnacle-loving snails. Checking them over before I added them to the aquarium, I found several healthy flatworms. No matter how strong a barnacle shell may be, these worms can slither through the cracks between plates, kill and eat the barnacle inside. Some flatworms may even eat the oysters.

*Barnacles may be hard to identify, but the thatched acorn has a black feeding foot. The barnacles that came home with me all have black cirri.