Wayne Moldenhauer, age 14, of Norfolk, Nebraska, for his question:
What are the gorgonians?
They belong in the warm world of green blue.water, speckled with sunbeams and freckled with shifting shadows. Their world is one where colorful undersea gardens are stocked with delicate foliage molded from stone and populated with dainty fishes that rival the rainbow. The gorgonians are at home in the watery wonderlands of coral reefs and in the tidal pools and lagoons of ocean islands.
Every skin diver yearns to behold the beauty of an underwater coral reef. Only there can we see the gorgonian and other coral structures in their natural colors. For
when the stony artwork is broken off and exposed to the surface air, it soon loses its garden hues. Only a few, including the one called precious coral, retain their colors in the dry air. In the water, a gorgonian structure may look like a spreading bush of rich purple. On land it turns to pasty white, though the stiff structure retains its shape for a long time.
The gorgonians belong to the eight sided branch of the coral class. Their stony structures are actually a handsome apartment house for a large colony of coral polyps. Each member builds his own single unit of limestone fragments. The gorgonian polyps build a family house around a core of fibrous, horny material. The entire structure is riddled with tunnels of circulating sea water. Many are lined with canals of living tissue that link all members of the colony together. The pliable center of the stony structure allows its graceful branches to bend and bow, wave and weave with the moving water.
The branching gorgonians often tower above the lower coral formations, like tall garden shrubbery. One gorgonian is the sea whip, with long skinny branches that lash around with the stirring tides. Another is the magenta colored sea plume that waves like a languid feather. The most delicate gorgonians are the multi colored sea fans that build half circle designs of dainty twiggery. The limey structures are built from pasty colored calcium carbonate and the color is added by living polyps.
Each gorgonian polyp has a gristly body with an eight sided pattern. He pokes a. circle of eight tentacles through his stony door and digests his food in a stomach with eight partitions. The tentacles that look like flowery petals are actually hungry fingers, fitted with mild stingers. They grab scraps of drifting seaweed and stun small creatures that happen to swim by. Then the little fingers stuff the food through a mouth in the center of the petal like circle.
The little polyp has specialized cells in his thick outer layer of jelly. They extract chemicals from the sea water and mold them into solid fragments of limestone and horny material. These fragments are used to build the stony branches and pliable center of the gorgonian structure.
Food and other substances pass through the tunnels that link the colony of polyps. So do the sex cells of the colony. The egg cells escape through the holes amid the tentacles and take their chances in the hungry sea. They pass through several complex life stages and few survive. The lucky ones finally settle on a firm base in the coral reef and start a building, based on a blueprint inherited from their ancestors.