Last night I posted a mystery photo that looked something like this:
This is probably a hard one to identify unless you've spent some time around marine invertebrates. Doesn't it look like a petroglyph? Here's another view:
These are the grazing marks of a limpet on an intertidal rock surface. A limpet scrapes microscopic algae off rocks with its radula — a long membranous ribbon (it looks somewhat like a tongue) that's armed with many rows of tiny teeth. Most of the time you don't get to see the results of their feeding bouts, but occasionally the conditions are just right and the route that the limpet took while grazing is revealed:
This patch of grazing marks was extensive! It was fun to look around to see the various paths that the limpet followed. (You can click on the images for larger versions.)
Munch, munch, munch!
I know this is a dumb Q. , but I was wondering...
ReplyDeleteis that rock really blue? Curious color.
A. in Seb.
No dumb questions...especially about colors! I think I would have said the darker color was a purplish black. I'm not sure that it's the rock itself, though, so perhaps my description was misleading. I think there might have been a darker crustose algae growing on the rock, too, and perhaps the lighter brown color was a different algae growing over that one -- so multiple layers of algae. At the time I was struck by the grazing pattern, but I should have paid more attention to the substrate, too!
ReplyDeleteJackie