Infrared satellite photos help track coral reef health

NASA is using Landsat to provide high-detail images of coral reefs to researchers, like this enhanced color image of an atoll

October 25, 2000
Web posted at: 1:39 PM EDT (1739 GMT)

GREENBELT, Maryland (CNN) -- Amid reports of a sharp rise in the death of the world's coral reefs, NASA released satellite images Wednesday that could provide a helping hand in locating dead or dying reefs.

Infrared images from NASA's Landsat 7 satellite highlight living, growing areas of coral, which appear bright red in the images. Areas where organisms have stopped growing on coral reefs appear gray.

Previously, coral reef health has been monitored by direct, underwater observation. Many scientists regard the sharp decline in reef health as alarming. United Nations-sponsored research estimates that 20 percent of the world's coral structures have died or become badly damaged in the past 20 years and that most of the world's coral could be similarly threatened in the next 50 years.

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The Landsat images represent a major shortcut in the costly, time-consuming process of monitoring reefs. "Reefs around the world are in ecological collapse," said researcher Phil Dustan of the College of Charleston. "We need to use remote sensing to help fight for their conservation."

The scientists say they have already archived 5,000 images from over 2,000 coral reefs. Coral exists throughout the world's tropical oceans.

Covering only 1 percent of the Earth's surface, coral structures contain an estimated 25 percent the planet's marine life -- earning the nickname "rainforests of the sea."

Pollution and damage from ship traffic have long presented a threat to coral reef health. But reef organisms are notoriously sensitive to changes in water temperature, and rising seawater temperatures believed to be linked to global warming have triggered a dramatic rise in the rate of coral decline in the last two decades.

In this Landsat image of a coral reef, areas of actively growing coral are colored bright red

The recent strong cycle of storms and weather changes linked to the El Nino and La Nina phenomena are also believed to have harmed coral reefs in many parts of the world.

The NASA team, composed of scientists from the University of South Florida, the College of Charleston in South Carolina and Dalhousie University in Nova Scotia, presented its research at the ninth annual Coral Reef Symposium in Indonesia this week.

One delegate, Australian scientist Clive Wilkinson, issued a stark invitation to divers, the backbone of a growing tourism industry built on the attraction of the reefs: "You have to go and look at the coral reefs now, as we are losing them."

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October 5, 2000
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September 8, 2000
Deep-sea corals: out of sight but in harm's way
August 10, 2000

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