When I was doing a lot of diving in southern California, some of my favorite subjects were gorgonians. Gorgonians are colonial invertebrates that, as a group, form flexible calcareous skeletons several feet across. The tiny individual polyps positioned on the branches of these “sea fans” wait for planktonic animals and small bits of food and debris to pass by in the current, at which time they grasp the particles with anemone-like tentacles and consume them. The overall fan-like shape of the gorgonian colony is usually oriented at right angles to prevailing currents to maximize the amount of plankton the polyps are able to capture.
Click the image to see a selection of my favorite gorgonian photos.
Red gorgonian on rocky reef, below kelp forest, underwater. The red gorgonian is a filter-feeding temperate colonial species that lives on the rocky bottom at depths between 50 to 200 feet deep. Gorgonians are oriented at right angles to prevailing water currents to capture plankton drifting by.