Today at the Hynes Convention Center in the heart of Boston, AAAS went “Into the Deep” with a symposium exposing deep-sea coral as an ancient organism (older than you’d think), a tool that can be used to measure climate change, and a victim of trawling, disappearing at an alarming rate.
Deep-sea corals may be the oldest known organisms in the ocean, says Brendan Roark, a geochemist from Stanford University. The oldest among them were once thought to be about 1,800 years old, but Roark’s new radio carbon dating studies show they can be as old as 4,200 years. The key to the new evidence was provided in the finding that these corals grow much more slowly than previously thought–it takes one species over 700 years to grow an inch. Flying in the face of conventional thinking, Alberto Lindner of the University of Sao Paulo in Brazil says that deep-sea corals are actually the ancestors of their shallow-water cousins. Warm, sunlit shallow seas were once thought to be the cradles of coral diversity. But Lindner’s DNA evidence shows that the more familiar shallow water corals, such as those that form the Great Barrier Reef, are actually the new comers on the evolutionary scene.
Scientists have only recently begun to descend into the oceans’ depth to collect samples of deep-sea corals, but they’re finding that it’s worth the trip: These slow-growing corals are more than just handsome ancestors—they are chock-full of climate change data. By analyzing their composition, scientists are now able to construct a better picture of ocean bottom temperatures and carbon cycles over the last few centuries. Previously, researchers had to rely on ice cores and ocean bottom sediment cores, which only provide century-by-century information. The deep-sea coral skeletons can reveal changes that occur from year to year, yielding a much more accurate picture of changes in the ocean.
But these deep-sea skeletons may not hold climate data for long: Bottom trawling, a fishing technique that scrapes the ocean floor, is quickly destroying corals in many parts of the world. The corals are hot spots of ocean diversity, as fish, crustaceans, and other ocean life tend to congregate around them, which in turn makes them appealing spots for fishing. And recent advances in technology are allowing bottom trawling to occur at greater depths than ever before, threatening corals scientists are only beginning to find. The symposium concluded with official launch of the Trans-Atlantic Coral Ecosystem Study, announced by J. Murray Robers, a scientist at the Scottish Association for Marine Science in the U.K. Beginning this year, the project will work towards using deep-sea corals to gain an understanding of North Atlantic climate history and ecology.