My Marine Life encyclopedia lists four species of acorn barnacles in our area. The tiny ones, barely a third of an inch across, coat the rocks at the high tide level. Below them are the Common Acorn Barnacles, not much bigger, living on larger rocks that are underwater most of the time. These are the ones we have to step on if we want to get to the lower levels.
And down where the rocks stand tall, we find the black-cirried* Thatched Acorn, up to 2 1/2 inches across. The Giant Acorn (6 inches diameter), the one with the pink cirri, is still farther out; we rarely see them here, except on floats. We explored Thatched Acorn territory last week.
|The outer shell of the large barnacles is covered with smaller ones, both the Common and Thatched. Mussels outline the base.|
On the tops of large, flattish rocks, the mix of small and large barnacles, viewed at eye level, looks like a Calvinesque landscape, all sharp rocks and recently-erupted volcanoes. Imagine yourself in a plane, coming in for a landing somewhere in that "river valley" on the upper right.
|All it needs is Spaceman Spiff|
|Sometimes the mussels and small barnacles completely engulf the larger ones. Do you see the mouth of the big guy here?|
|I noticed that quite a few of the mussels in this zone had "beards". Or maybe I should say, "stubble".|
|Barnacles growing away from the crowd sometimes had a pinwheel base, formed from the ends of the downward ridges. There's a bearded mussel on the far right, and below it, a common acorn barnacle.|
*Is that a word? Adjective, meaning, "having cirri". The barnacle's cirri are the fan-shaped feeding parts that the barnacle sweeps through the water.