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Scientists: Coral Reefs Spared in Tsunami

December 28, 2005

BOSTON — Gregory Stone was on a diving expedition off Fiji on December 26, 2004, when the first sketchy reports reached his ship about the undersea earthquake that had spawned a catastrophic tsunami in South Asia. Amid his horror over the human toll, another thought quickly formed in the scientist’s mind: What would be the impact of this natural disaster on the region’s stunningly beautiful and ecologically critical coral reefs?

Several months later Stone, vice president of global marine programs for the New England Aquarium, traveled with a team to Phuket, the Thai resort island that became well-known to the world in the days after the tsunami. Over the next two weeks, the team made approximately 500 dives at 56 sites, surveying the reefs to determine how badly they had been damaged and how long they might take to recover.

They found destruction, but also hope.

“In the fullness of time, the tsunami was just another bad day in the life of the coral reef. It will recover,” said Stone, who spoke to the Associated Press from New Zealand, site of his latest expedition.

Stone concluded that it was the long-term intervention of humans, and not the momentary havoc wreaked by the tsunami, that posed the greatest threat to the reefs.

“What we found was that the effects of human activity – overfishing, global warming – actually had a stronger impact than the tsunami,” he said. “It really woke us up to what is happening to the coral reefs of the world and what people are doing to them.”

Wanting a palpable connection to the event, Stone’s team chartered the Philkade, a 100-foot vessel that had been ferrying tourists to a popular dive site when the giant wave struck. Though pushed and spun around wildly, the Philkade, its crew and passengers came away remarkably unscathed.

The report, published by the aquarium and in the December issue of National Geographic, found that about 14 percent of the coral reefs in the tsunami zone surveyed by the team were severely damaged or destroyed. Roughly 50 percent sustained moderate damage and 36 percent survived with little or no damage.

In general, shallower reefs were harder hit than those in deeper water.

In some cases, Stone said the damage came from the physical energy of the wave, which dislodged the coral, “rolling it over and over again until it was killed.” In other cases, the tsunami bulldozed massive piles of sand, smothering the living coral; and in yet other cases, the coral was damaged by manmade objects, including cars and houses, that were pulled into the ocean by the retreating wave.

Among the divers on the expedition was Alan Dynner, a Boston business executive and chairman of the aquarium’s board of trustees. He saw examples of the tsunami waves acting “like a steamroller, pulverizing everything in front of them.”

Dynner, an avid diver, said the tsunami tore loose coral heads the size of tractor-trailers and left behind “giant underwater sand dunes,” something he had never imagined seeing.

Coral reefs are sometimes called the rain forest of the sea, because of their ecological importance. They are important, Stone said, because “they are the most beautiful, most diverse and also the most fragile part of the ocean.”

But they are also critical to the human inhabitants of the region, yielding the fish that are a staple of the local diet. Their colorful beauty, which is created by the symbiotic relationship between the coral animals and algae, attracts tourists who contribute to the local economy.

And, said Stone, researchers have found that coral reefs, when healthy, can act as protective buffers against future tsunamis.

On the Net:

New England Aquarium: http://www.neaq.org

National Geographic Society: http://www.nationalgeographic.com/