WAKATOBI, Indonesia: Red anthia fish and rainbow-colored wrasse dart among the glittering reefs of Indonesia's Wakatobi archipelago, as eagle rays and barracudas cruise past in the blue depths. It's hard to believe Wakatobi is anything but a thriving marine paradise, packing a bewildering abundance of life that supports 100,000 people and contributes millions of dollars to Indonesia's economy. But scientists are worried. Last year, coral bleaching caused by higher sea temperatures wreaked havoc across the Coral Triangle, a region of rich tropical reefs spanning much of Southeast Asia and almost all of Indonesia. Up to 70 percent of the coral in Wakatobi, off the southeastern tip of Sulawesi island, was totally or partially bleached. In Aceh province, off the northern tip of Sumatra, as much as 90 percent was killed, scientists said. Experts from environmental groups The Nature Conservancy and WWF, as well as the Indonesian government, returned to Wakatobi last month to see if the marine park's reefs had bounced back. Over two weeks of diving at sites with names like Table Coral City and Blue Hole, the team looked for signs of long-term damage or resilience, in the hope of learning more about how reef systems respond to climate-related stresses. “In Aceh about 90 percent of the coral bleached, and that included some of the really big varieties that are hundreds of years old and had survived the (2004) tsunami but died because of the bleaching,” said Joanne Wilson, deputy director for science in TNC's Indonesia Marine Program. “Very fortunately in Wakatobi ... it seems that only about five to 10 percent of the corals actually died. We're very lucky here.” Bleaching occurs when corals respond to stress, such as stronger than normal direct sunlight or elevated sea temperatures, by expelling the algae that live inside them and give them their brilliant colors. In normal conditions the symbiotic algae provide the corals with nutrients, and without them the corals turn white and can die within days. They may also recover, depending on the circumstances. Wilson described the “eerie” experience of diving on wintry, frozen-looking reefs during the height of the bleaching at Wakatobi last year, the warmest year on record. “I saw that a lot of the corals were affected by the bleaching to various stages. Some were completely white but still alive,” she said. Scientists feared a repeat of the 1998-1999 global bleaching that was linked to the El Nino and La Nina weather cycles in the Pacific Ocean. About 16 percent of the world's reefs died in that crisis, providing a wake-up call to scientists about the dangers posed to reef systems — and the millions of people who depend on them — from global warming. Ove Hoegh-Guldberg, the director of the Global Change Institute at the University of Queensland in Australia, said the effects of El Nino and La Nina were being magnified by “background warming” linked to general climate change. “Over the next five to 10 years, we will probably return to fairly serious bleaching conditions,” he said. A study by two dozen conservation and research groups led by World Resources International released last month said that without quick action to arrest global warming and reduce other human impacts, the world's reefs could be wiped out by 2050, with grave implications for humanity as a whole.
