Coral Layers Good Proxy for Atlantic Climate Cycles

Tree rings may tell how old a tree is, but the rings or annual bands in some skeletal coral may tell not only the age of the animal, but also something of the dynamics of the ocean in which it grew, according to Penn State and University of Miami researchers. “Some coral grows like a tree; each year a complete layer with both a high and low-density skeletal calcium carbonate band is formed by the coral animal,” says Dr. Lisa Greer, assistant professor of geosciences. “Not all corals create rings, but the massive corals like boulder star coral or pin cushion coral do.”