Skip to main content /TECH with /TECH

Study names Top 10 coral hot spots

'A system important for global biodiversity and economics'

The butterfly fish depends on corals for food and shelter and is found only in the Red Sea.  Destruction of that area's reefs could mean the loss of this fish, the Chaetodon semilarvatus.
The butterfly fish depends on corals for food and shelter and is found only in the Red Sea. Destruction of that area's reefs could mean the loss of this fish, the Chaetodon semilarvatus.  

By Tiffany Campbell
CNN Sci-Tech

(CNN) -- Seen from above, coral reefs appear to lie like delicate thumbprints, edging the coasts of Australia, New Guinea, the Philippines.

On closer inspection, they're beautiful, breathing monuments that feed nations and bring in billions of dollars in international revenue. And they may be dying.

A new study has identified 10 of the most threatened and diverse coral-reef "hot spots," with reefs off the Philippines, in the Gulf of Guinea and near the Sunda Islands of Indonesia topping the list.

The study was conducted by the Center for Applied Biodiversity Science, a division of Conservation International. It contradicts a going assumption made by many that marine species are unaffected by human activities because of their vast geographical ranges.

Coral reefs cover just two-tenths of 1 percent of the oceans' area, but are estimated to provide home and habitat to one-third of all marine fish species and tens of thousands of other species, and yield 6 million metric tons of fish catch annually.

How important do you feel conservation of coral reefs is?

Moderately important.
Mildly important.
No big deal.
View Results
Conservation International has identified 10 regions in which coral reefs are most seriously threatened.  Click here for an interactive look at them.

But these systems are fragile. They're under intense pressure from human activity and face an uncertain future.

Economic impact

"For the first time (we've) studied the biodiversity of the reefs, looking at what was unique and special," says Dr. Tim Werner, senior director with Conservation International's marine division and co-author of the report. "It's a system important for global biodiversity and economics. We just didn't have the level of knowledge of where the priorities were."

Conservation International defines hot spots as areas facing a significant threat of habitat loss while harboring diverse species found nowhere else.

"On a global scale, coral reefs supply a huge amount of food and protein for hundreds of millions of people" in 30 countries, says Roger Griffis, a policy advisor for the United States' National Oceanic and Atmospheric Administration (NOAA), citing studies done by the World Bank and the World Resources Institute.

A NOAA study indicates that in the Florida Keys, healthy reef systems have an estimated asset value of $7.6 billion in impact on sales, income and employment support. Reefs also protect coastal communities by acting as buffers against waves and severe weather.

As possible reservoirs of new medicines, particularly biochemicals, the reefs can be of great interest to the medical community, Griffis says.

Corals are tiny, plant-like animals. When they die, their skeletons form reefs that can support living coral and other marine life for thousands of years. Some of the largest coral colonies found among U.S. reefs today were alive before the European colonization rivaling old-growth forests in longevity, according to information provided by NOAA.

Dangers of the not-so-deep

"By actually mapping the ranges, we're able to show that species have limited ranges and are therefore much more susceptible to the threat of extinction by humans," Werner says.

Threats come from both land and sea. Corals, Griffis says, need clean, clear warm water to remain healthy. Agriculture, deforestation and development pour sediments, nutrients and other pollutants into the sea. Overfishing and destructive fishing are also leading causes of reef ecosystem degradation.

Some fishing techniques use cyanide to stun the fish so they can be captured live for the lucrative aquarium industry. The cyanide degrades the corals left behind and often kills species not targeted by fishermen.

Intemperate threats

From Conservation International's Tim Werner, here are two views of a reef -- one teeming with life and the other blasted by one of the forms of
From Conservation International's Tim Werner, here are two views of a reef -- one teeming with life and the other blasted by one of the forms of "destructive fishing," in this case using dynamite.  

There are also concerns with climate change, Griffis says. Corals survive within one degree Celsius of their thermal death mark, which means that even a one-degree change can affect the reef.

When corals are stressed by high temperatures, the algae that live within them get expelled from the reef, resulting in bleaching, Griffis said. The algae give the coral its color, so when they're gone, the reefs have an almost white appearance. This phenomenon has been documented worldwide.

"Imagine walking out of your house one day, and all the leaves on your trees have turned white," Werner says. "It's creepy."

Floating the study results

Conservation International says the 10 hot spots identified in the new study account for less than two-tenths of 1 percent of the oceans, but claim 34 percent of "restricted-range" species, or life found only in specialized areas. Many oceanic hot spots are adjacent to land areas that also have environmental challenges.

Conservation International's Werner says the Center for Applied Biodiversity Science conducted this study in order to identify priority areas for coral reef conservation.

"We wanted to get very strategic in how we approach the conservation of coral reefs," Werner says. "We think one of the best tools for conservation are marine protected areas -- parks in the sea. They've shown to be very effective."

He cites a marine reserve off Apo Island, in the Philippines.

"For years the coastal fisherman were skeptical about setting up reserves; they saw it as taking away their livelihood," Werner says. "But within a couple of years, the overall fish-catch went up." The reserves act as protected habitat and allow fish to grow larger.

"That's the big benefit of marine reserves," says Werner. "Not only do they protect what's in their boundaries, but they also help improve the surrounding area. It just seems to be a win-win situation."

A special report on coral-reef hot spots is part of this week's Next@CNN -- CNN's weekly TV magazine on science, space, technology and the environment. See it at 1 p.m. EST on Saturday and 4 p.m. EST on Sunday.


Note: Pages will open in a new browser window
External sites are not endorsed by CNN Interactive.


Back to the top