Chutima Sidasathian and Alan Morison
phuketwan.com 10 May 10
BLEACHING has whitened 90 percent of Phuket's and Thailand's coral reefs amid concern about an unusually late hot season that has marine biologists concerned.
Divers confirm the widespread bleaching, as well as the presence of increasing numbers of jellyfish.
Niphon Phongsuwan, the coral reef specialist at the Phuket Marine Biology Centre, said reefs in both the Andaman Sea and the Gulf of Thailand had begun the bleaching process in the first week of April, as sea temperatures remained unusually high.
"The key temperature is 30.1 degrees," he said. "Unless the temperature drops from there, bleaching begins, and continues until the sea grows cooler."
Diver and underwater photographer Adriano 'Wetpixel' Trapani, CEO of Dive Clan Co, confirmed that sea temperatures had remained high, triggering concerns about the coral.
"It is alarming, but I wouldn't be too concerned," Mr Trapani said. "A similar event bleached coral in the Maldives a few years ago and the reefs there have returned to normal. It's a cyclical thing, probably caused by the El Nino phenomenon.
"At first we thought it might just be patches of coral that had been destroyed by the crown of thorns starfish, but now we know differently because the bleaching is so even.
"I was here for the tsunami when some reefs were damaged but now they are back the way they were." He said the larger threats to the reefs remained over-diving and exploitation.
Khun Niphon said coral bleaching occurred on Phuket's reefs between 1991 and 1995. "In that time, there was less cloud protection from the sun and so quite a bit of coral died," he said. From 2003 to 2005, a less damaging cycle occurred, but the coral survived.
"Bleaching does not mean death for the coral, provided the monsoons come in time," he said. "Coral lives on, and recovers, as long as the sun does not become too intense for too long."
No area around Phuket had escaped bleaching, Khun Niphon said. With concern growing about long-term global warming, Khun Niphon is researching which types of coral are most resistant to bleaching so that the hardiest kinds of coral can be encouraged in future.
While the event could be coincidental, Mr Trapani said he had noticed an increasing number of jellyfish in waters near Phi Phi island, between Phuket and Coral Island, on the way to Raya island and in Chalong Bay, on Phuket. The jellyfish were capable of inflicting a mild sting, like sunburn, but not dangerous.
A spokesman for Phuket's weather bureau said that the monsoon usually came soon after the Songkran Festival of mid-April, but this year, extending into May, Phuket and southern Thailand had yet to see the heat break.
The spokesman preferred not to give his name, and said he had no idea why the monsoon was so late this year.
The bureau does not analyse year-on-year statistics and is therefore unable to give detailed information about possible future trends.
There is no way of knowing when the extended spell of heat will break this year.
Bleaching coral off Phuket's Nai Harn beach
Bleaching coral off Phuket's Nai Harn beach
Phuket Coral Reefs Still Hostage to Sunshine
Chutima Sidasathian: Phuketwan 13 Jun 10;
PHUKET'S coral reefs remain at risk despite the arrival of cooling storms, Phuket marine Biology Centre expert Niphon Pongsuwan says. The reefs are one of Phuket's prime tourist attractions.
Bleaching has struck 90 percent of the coral reefs around Phuket, he added, and already between 10 percent and 40 percent could not be saved even if sea temperatures dropped quickly now.
Greater than usual exposure to hot sun in warmer than normal water has placed the entire Andaman region's reefs at risks this year. Other reefs around Thailand and the Great Barrier Reef off Australia have also been affected.
Khun Niphon went diving off Phuket on Tuesday and placed reef temperatures at 30.5 degrees. Prolonged exposure at 31 degrees or above is what has put the colorful reefs at risk.
Last week's thunderstorms and clouds over Phuket and the Anbdaman Sea have helped, but perhaps not enough.
''Half a degree is better however we still need the temperature to move to 29 degrees quickly or there could be residual damage and death,'' he said.
Loss of reefs around Phuket ''would not take many years'' to replace because they were fast-growing varieties, he said. But he said more hot seasons could worsen the situation quickly. ''We just can't tell from season to season because so many factors now come into play,'' he said.
More sophisticated measurement techniques involving taking the temperatures of reefs regularly would help diagnosis but not treatment, he said.
Greater than usual exposure to hot sun in warmer than normal water has placed the entire Andaman region's reefs at risks this year. Other reefs around Thailand and the Great Barrier Reef off Australia have also been affected.
Khun Niphon went diving off Phuket on Tuesday and placed reef temperatures at 30.5 degrees. Prolonged exposure at 31 degrees or above is what has put the colorful reefs at risk.
Last week's thunderstorms and clouds over Phuket and the Anbdaman Sea have helped, but perhaps not enough.
''Half a degree is better however we still need the temperature to move to 29 degrees quickly or there could be residual damage and death,'' he said.
Loss of reefs around Phuket ''would not take many years'' to replace because they were fast-growing varieties, he said. But he said more hot seasons could worsen the situation quickly. ''We just can't tell from season to season because so many factors now come into play,'' he said.
More sophisticated measurement techniques involving taking the temperatures of reefs regularly would help diagnosis but not treatment, he said.
