Ok, here's the first real data I've seen, from today's Science magazine. Describes surveys of 175 sites in the Andaman:
"Half or more of the coral was missing from 13% of the sites, says Thamasak Yeemin, a marine scientist from Thailand's Ramkhamhaeng University in Bangkok. About 40%, though, seemed untouched."
***
Powerful Tsunami's Impact on Coral Reefs Was Hit and Miss
by Elizabeth Pennisi
Early surveys suggest that coral reefs around the Indian Ocean survived December's tsunami in better shape than many had feared. In the sites where researchers have looked, "only a few areas were severely damaged, and the rest should recover rapidly in the next 5 to 10 years," says Clive Wilkinson, a marine scientist with the Australian Institute of Marine Science in Cape Ferguson. In some places, divers are already helping that recovery with restoration efforts.
In the immediate aftermath of the 26 December tsunami, Wilkinson and others feared the worst. The wave's awesome power, as well as sediment, pollutants, and debris washed onto the reefs when the wave retreated, posed major threats, says Russell Brainard, a U.S. National Oceanic and Atmospheric Administration oceanographer based in Honolulu. If eroded mud and silt buried a reef, they could destroy the corals.
Off the coast of Thailand, however, many reefs were spared. In January, volunteers and academic and government marine scientists took to the water for a first look. They evaluated 175 sites in the Andaman Sea along the west coast of Thailand, rating each according to the degree of impact. Half or more of the coral was missing from 13% of the sites, says Thamasak Yeemin, a marine scientist from Thailand's Ramkhamhaeng University in Bangkok. About 40%, though, seemed untouched.
Also last month in Thailand, Sakanan Plathong, a marine biologist at Prince of Songkla University in Had Yai, and 60 assistants armed with cameras spent 3 weeks combing a smaller area, the Similan Islands, one of the country's best dive spots. "In general most Similan islands that are dive sites are still in good condition," says Plathong. Only about 15% of the area's coral was severely damaged.
David Obura of CORDIO East Africa--a collaborative coral research program in the Indian Ocean--in Mombasa, Kenya, has similarly good news about the African coast. "We were generally surprised at the [small] and very patchy damage to the coral reef communities," he says.
Figure 1 Uprooted. The tsunami left some reefs untouched, but in many places--as shown above--it knocked down corals of all shapes and sizes.
CREDIT: KEVIN MOSES/AP PHOTO
Although turbid water prevented local government and academic divers from looking at six of the 10 sites in the Seychelles selected for a preliminary assessment, the survey indicated that only 13% of the coral colonies were damaged.
The reefs that were affected suffered different levels of damage, some repairable and some not. Corals were toppled over, sometimes covered with sand and rubble. In some places, meter-high sea fans were pummeled and knocked off their perches. Several reefs were littered with debris--logs, beach beds, towels, palm trees, boat engines, and beach umbrellas. These wave-driven objects "become like bulldozers," says Brainard. "They severely erode the coral habitat."
After the tsunami, Plathong realized he had to act fast to save any damaged corals. He brought a brigade of 136 volunteer divers to some of the worst places in the Similan Islands. The divers worked to right corals and were able to salvage those that hadn't slid beyond reach down the sloping sea floor. They propped up sea fans--a temporary fix until they could return with marine cement. They also removed debris, although heavy objects had to be left behind. The repair efforts benefited in one way from the tsunami's power: The wave was so strong that potentially lethal silt and mud washed far out to sea in many areas.
Yet there were places "where the reefs were just planed off and stripped to bare rock," says Wilkinson. In another part of Thailand, three of four reefs surveyed were decimated. In some places, divers measured 5 millimeters of sediment on top of the corals. The reefs off the Tamil Nadu cost in Southeast India also appear to be severely damaged, as was coral off the Andaman and Nicobar Islands. "It will take some time before we can build a proper picture of the ecological ramifications of this disaster," says Wilkinson.
"Half or more of the coral was missing from 13% of the sites, says Thamasak Yeemin, a marine scientist from Thailand's Ramkhamhaeng University in Bangkok. About 40%, though, seemed untouched."
***
Powerful Tsunami's Impact on Coral Reefs Was Hit and Miss
by Elizabeth Pennisi
Early surveys suggest that coral reefs around the Indian Ocean survived December's tsunami in better shape than many had feared. In the sites where researchers have looked, "only a few areas were severely damaged, and the rest should recover rapidly in the next 5 to 10 years," says Clive Wilkinson, a marine scientist with the Australian Institute of Marine Science in Cape Ferguson. In some places, divers are already helping that recovery with restoration efforts.
In the immediate aftermath of the 26 December tsunami, Wilkinson and others feared the worst. The wave's awesome power, as well as sediment, pollutants, and debris washed onto the reefs when the wave retreated, posed major threats, says Russell Brainard, a U.S. National Oceanic and Atmospheric Administration oceanographer based in Honolulu. If eroded mud and silt buried a reef, they could destroy the corals.
Off the coast of Thailand, however, many reefs were spared. In January, volunteers and academic and government marine scientists took to the water for a first look. They evaluated 175 sites in the Andaman Sea along the west coast of Thailand, rating each according to the degree of impact. Half or more of the coral was missing from 13% of the sites, says Thamasak Yeemin, a marine scientist from Thailand's Ramkhamhaeng University in Bangkok. About 40%, though, seemed untouched.
Also last month in Thailand, Sakanan Plathong, a marine biologist at Prince of Songkla University in Had Yai, and 60 assistants armed with cameras spent 3 weeks combing a smaller area, the Similan Islands, one of the country's best dive spots. "In general most Similan islands that are dive sites are still in good condition," says Plathong. Only about 15% of the area's coral was severely damaged.
David Obura of CORDIO East Africa--a collaborative coral research program in the Indian Ocean--in Mombasa, Kenya, has similarly good news about the African coast. "We were generally surprised at the [small] and very patchy damage to the coral reef communities," he says.
Figure 1 Uprooted. The tsunami left some reefs untouched, but in many places--as shown above--it knocked down corals of all shapes and sizes.
CREDIT: KEVIN MOSES/AP PHOTO
Although turbid water prevented local government and academic divers from looking at six of the 10 sites in the Seychelles selected for a preliminary assessment, the survey indicated that only 13% of the coral colonies were damaged.
The reefs that were affected suffered different levels of damage, some repairable and some not. Corals were toppled over, sometimes covered with sand and rubble. In some places, meter-high sea fans were pummeled and knocked off their perches. Several reefs were littered with debris--logs, beach beds, towels, palm trees, boat engines, and beach umbrellas. These wave-driven objects "become like bulldozers," says Brainard. "They severely erode the coral habitat."
After the tsunami, Plathong realized he had to act fast to save any damaged corals. He brought a brigade of 136 volunteer divers to some of the worst places in the Similan Islands. The divers worked to right corals and were able to salvage those that hadn't slid beyond reach down the sloping sea floor. They propped up sea fans--a temporary fix until they could return with marine cement. They also removed debris, although heavy objects had to be left behind. The repair efforts benefited in one way from the tsunami's power: The wave was so strong that potentially lethal silt and mud washed far out to sea in many areas.
Yet there were places "where the reefs were just planed off and stripped to bare rock," says Wilkinson. In another part of Thailand, three of four reefs surveyed were decimated. In some places, divers measured 5 millimeters of sediment on top of the corals. The reefs off the Tamil Nadu cost in Southeast India also appear to be severely damaged, as was coral off the Andaman and Nicobar Islands. "It will take some time before we can build a proper picture of the ecological ramifications of this disaster," says Wilkinson.
