Tuesday, April 28, 2009
This acrylic painting of a barnacle cluster for my class in Oil and Acrylic painting took me on quite a little side-journey. This is a shell, basically, of calcium carbonate like all shells.
Surprisingly, barnacles are not mollusks but a form of arthropod and therefore more closely related to crabs and lobsters. They secrete the substance the their little "towers" are made from, and build them up little by little over time.
The holes in the tops of the little towers are closed using two plate-like structures that close off the openings when the barnacle doesn't wish to be disturbed, like when there's a marauding whelk in the neighborhood. They are opened at feeding time, when food is attracted by waving featherlike appendages to attract plankton into the structure.
The taller the structure (compared to the neighbors) the more plentiful the food. I guess it's good to live in the penthouse, if you're a barnacle.
These guys are pretty busy builders, and will establish whole towns on the underside of a boat if strict zoning ordinances are not enforced.
The shells are fun to paint, though!