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  Yahoo News 8 May 07
Study ties coral disease to warmer oceans
By Jim Loney

Yahoo News 1 May 07
Coral Reef Devastation Linked to Global Warming
LiveScience Staff LiveScience.com

Coral disease outbreaks have struck the healthiest sections of Australia's Great Barrier Reef, and a new study has conclusively linked disease severity to ocean temperature and climate change for the first time.

"With this study, speculation about the impacts of global warming on the spread of infectious disease among susceptible marine species has been brought to an end," said Don Rice, director of the National Science Foundation's Chemical Oceanography Program, which helped fund the research.

The study tracked an infection called white syndrome in the Great Barrier Reef, the largest coral reef system in the world.

Coral colonies live atop limestone scaffolding, which is built from the secretions of the coral creatures called polyps. The vivid colors of the coral come from the symbiotic algae that live in the polyps and supply them with much of their nutrients. When disease or stressful environmental conditions, such as changes in ocean temperature, strike the reef, the polyps expel their algae, making them appear pale.

Corals are critical to the survival of some commercial marine species and help buffer low-lying coastal areas.

"More diseases are infecting more coral species every year, leading to the global loss of reef-building corals and the decline of other important species dependent on the reefs," said study lead author John Bruno of the University of North Carolina.

The stressful rise in ocean temperatures due to global warming, coupled with the close living quarters of corals may make it easy for infection to spread, according to the study published in the May 1 online issue of PLoS Biology.

"We've long suspected that climate change is driving disease outbreaks," Bruno said. "Our results suggest that warmer temperatures are increasing the severity of disease in the ocean."

Yahoo News 8 May 07
Study ties coral disease to warmer oceans
By Jim Loney

Warmer sea temperatures are linked to the severity of a coral disease, according to a study on Australia's Great Barrier Reef that offers a dire warning about global warming's potential impact on the world's troubled reefs.

The 6-year study released on Monday tracked the relationship between water temperature and the frequency of a coral disease called white syndrome across more than 900 miles of the world's largest coral reef.

"We've linked disease and warm water, which is one of the aspects of global warming," said John Bruno, the study's lead author. "Our study suggests as global warming warms the oceans more and more, we could see more disease outbreaks and more severe ones."

The results of the study, funded by the U.S. National Science Foundation, were to be published on Tuesday in the online journal PLoS Biology.

Researchers have suspected for years that warm sea temperatures were responsible for disease outbreaks on coral reefs. But Bruno said the study was the first to conclusively connect the two.

Reefs are undersea rock formations built by tiny animals called coral polyps. They are important habitats and nurseries for fish and other sea creatures.

Scientists estimate about a quarter of the world's coral has been permanently lost and another 30 percent could disappear over the next 30 years.

The study tracked the fate of 48 reefs across the Great Barrier Reef. They were resurveyed each year for six years and disease data were compared with data on ocean temperature taken from U.S. National Oceanic and Atmospheric Administration satellites.

HOT WATER

Two years ago, unusually hot water across the Caribbean Sea was blamed for a massive surge of coral bleaching, an ailment that turns corals white, and a subsequent wave of deadly diseases that attacked reefs across the region.

In some locations, scientists found a 25 to 30 percent loss of coral and centuries-old corals were killed.

Coral bleaching is a different phenomenon from white syndrome.

In the NSF study, scientists found white syndrome, an ailment that has appeared across the Pacific, flourished when the sea temperature rose. In 2002, for example, the frequency of the disease increased 20-fold after a year in which the region saw its second warmest summer.

The study found that the effect of temperature was "highly dependent" on the density of the coral cover.

Outbreaks of white syndrome followed unusually warm temperature on reefs with greater than 50 percent coral cover.

The healthiest reefs suffered the most severe disease outbreaks, probably because they had the most dense concentrations of coral polyps.

"It's the same natural principle as what happens when humans are packed together in tight circumstances and they are more prone to disease," said Bruno, an assistant professor of marine ecology at the University of North Carolina.

A host of corals were affected, many of them the important "reef-building" corals that construct the limestone foundation on which coral polyps live.

Bruno said while the study focused on white syndrome, "there is no reason to suspect" that other coral diseases would not be similarly affected by warmer ocean temperatures.

"We are working on the same kind of experiments with yellow band disease," he said. "It's starting to look like there is a role of temperature in driving yellow band disease too."
links
Barrier Reef 'dead in 20 years'
By Rosemary Desmond news.com.au 6 Apr 07

Acid Oceans Threatening Marine Food Chain, Experts Warn Scott Norris National Geographic 17 Feb 07

Global warming threatens Australia's Barrier reef
By Rob Taylor Yahoo News 2 Feb 07

Research in Pacific shows ocean trouble Acidity rises, oxygen drops, scientists find
By Lisa Stiffler Seattle Post-Intelligencer 3 Apr 06

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