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Crystal Clear

MIT-WHOI Joint Program student Tom DeCarlo holds a vial containing aragonite, a crystal form of calcium carbonate, the mineral that reef-building corals use to build their skeletons. To make aragonite, corals extract calcium and carbonate ions from seawater. By manipulating the chemistry of seawater samples in the lab, DeCarlo and Michael Holcomb of the University of Western Australia are able to obtain insights into the mechanisms corals use to build aragonite skeletons and how they may be adversely affected by ocean acidification caused by rising carbon dioxide levels in the air and ocean.(Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)