Corals Reveal Past Climate

WHOI paleoclimatologist Konrad Hughen studies the history of Earth’s changing climate—using corals. The tiny living coral animals, known as polyps, lay down a new layer of calcium carbonate skeleton each year, just as trees produce annual growth rings. By analyzing the chemical make-up of cores he extracts from coral colonies, Hughen can estimate how water temperatures have changed over the past several hundred years. Hughen normally drills cores from fast-growing Porites species, but the skeletons of large brain corals such as this Red Sea Diploria also contain a history of climate change. (Photo Konrad Hughen, Woods Hole Oceanographic Institution)