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Coral reefs on 'slippery slope to slime'

July 7, 2008 | 11:37 am

Hawkfish_green2

Federal scientists today opened the International Coral Reef Symposium in Fort Lauderdale, Fla., with dismal news: About half of the remaining coral reefs in U.S. waters are in poor or fair health.

The findings released by the National Oceanic and Atmospheric Administration were part of a comprehensive assessment of coral reefs in the Florida Keys, Hawaii and in U.S. waters around islands sprinkled throughout the Caribbean and the Pacific Ocean.

"The condition of our nation's corals have been declining for several decades and half of them are in poor or fair condition," said Jenny Waddell, who edited the 569-page health assessment written by 270 co-authors.

Corals around the world face multiple stresses that include overfishing of algae-eating fish that keep coral reefs clean; sewage and fertilizer runoff that turns the water a soupy green and shades corals from the sunlight they need or overgrows the reefs with suffocating mats of algae.

Other problems associated with global warming now contribute to the poor health. Warmer than usual seawater stresses corals to the point that they "bleach"  bone white, expelling algae from their skeletons that give them their color. Some of these tiny animals recover but many fall victim to disease or otherwise die.

In addition, scientists at the meeting here have been focusing on oceans becoming more acidic as they absorb nearly half of the carbon dioxide released by smokestacks and tailpipes into the atmosphere. If the trends continue, it will make it difficult or impossible for corals to extract the material from alkaline seawater that they need to build their shells.

Reefs in the Caribbean have been particularly hard hit since the last U.S. coral reef health assessment in 2005, Waddell said. A massive bleaching event killed about half of the corals at monitoring stations in Puerto Rico and the U.S. Virgin Islands, she said. At some spots, 90% of the corals died.

The problem, said Kacky Andrews, program manager of the federal Coral Reef Conservation Program, is that so many of these stresses are hitting reefs all at once.

"There is no quick fix," Andrews said.

She characterized the health report card as a call to action for governments, businesses and citizens to  do their part to save reefs that provide an important protection against storms and a habitat for tropical fish, as well as providing food and recreation. She noted that a global campaign to raise awareness, the International Year of the Coral Reef, lists recommendations on what needs to be done.

Without broad-based action, Andrews said, the future looks grim. To give a sense of how grim, she quoted Jeremy Jackson, an influential scientist at Scripps Institution of Oceanography who says that  colorful coral reefs are quickly turning into slimy mats of algae and bacteria.

"Jeremy Jackson has coined the term, slippery slope to slime," Andrews said.

-- Kenneth R. Weiss, from Fort Lauderdale, Fla.

Photo: A hawkfish is shown among branching coral. Credit: Chuck Savall

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