Peeking at Coral Reefs from Space
News story originally written on June 4, 2003

This is a picture of coral reefs in the Red Sea as seen from the International Space Station on May 20, 2003. Click on image for full size (198K JPG ) Courtesy of NASA

On May 20, 2003, the crew of the International Space Station took a photo of the Earth below them that shows more than a dozen coral reefs sitting in the shallow waters of the Red Sea. The light blue parts indicate coral reefs just under the sea surface. Only six percent of the Earth’s coral reefs are in the Red Sea. Most others are in tropical parts of the western Pacific Ocean or the Caribbean Sea.

Some researchers dive into the water and study reefs up-close, but other researchers want to see the big picture. Looking at reefs from the ISS or Earth-observing satellites allows scientists to figure out if reefs around the world are healthy. They can’t see individual reef creatures, but they can figure out how much of a reef is covered with living coral or how much of the coral has died.

In fact, the world’s coral reefs are in trouble. Threatened by pollution, warming sea surface temperatures, and new coral diseases, the number and quality of reefs is declining worldwide. Thanks to satellites and the ISS we are able to keep track of reef health by looking from above.

Called sunglint, the bright spot in the lower right side of this picture is the reflection of the Sun overhead. Meandering white lines show where the sunlight reflects off films on the water surface. Some of the oily film at the sea surface is natural, produced by marine animals, but cargo ships leave much of it behind as they leak small amounts of oil and gas. The reflections form this meandering pattern as waves and currents concentrate the oily surface film into a pattern. These patterns are helpful for researchers trying to understand how water flows around reefs, but the oil is most likely not helpful to the reefs themselves.

This is a picture of coral reefs in the Red Sea as seen from the International Space Station on May 20, 2003. Click on image for full size (198K JPG) Courtesy of NASA

Take a look at this picture! The light blue parts are coral reefs just under the surface of the Red Sea. The crew of the International Space Station (ISS) took the picture on May 20, 2003 as they looked down at the Earth below them.

Some researchers dive into the water and study reefs up-close, while other researchers want to see the big picture. Looking at reefs from the ISS or Earth-observing satellites lets scientists figure out whether reefs around the world are healthy. They can see how much of the reef has living coral on it and how much of the coral has become sick and died.

In fact, the world’s coral reefs are in trouble. Threatened by pollution, warming sea temperatures, and coral diseases, the number of coral reefs is declining worldwide. Thanks to satellites and the ISS we are able to keep track of reef health by looking from above.

The bright spot in the lower right side of this picture is the reflection of the Sun overhead. Astronauts call the reflection sunglint. It makes it difficult to see all the reefs, but it is interesting to scientists who study how water flows around reefs. The sunglint forms a meandering pattern as waves and currents move oils around the sea surface. Some of the oily film at the surface is natural, produced by animals in the sea, but much of it is from oil and gas that is left behind by cargo ships.

This is a picture of coral reefs in the Red Sea as seen from the International Space Station on May 20, 2003. Click on image for full size (198K JPG) Courtesy of NASA

Look at this picture! The light blue parts are coral reefs just under the water’s surface. How many reefs do you see?

The crew of the International Space Station (ISS) took this picture while looking down at the Earth below them on May 20, 2003. It shows coral reefs in the Red Sea.

Some scientists dive into the water and study reefs up-close. Other scientists can study reefs from very far away. By looking at reefs from the ISS or Earth-observing satellites, scientists can figure out if reefs around the world are healthy. They can see how much of a reef has living coral on it and how much coral has become sick and died.

The world’s coral reefs are in trouble. Each year there are less healthy reefs. Pollution, warming oceans, and new coral diseases threaten them. Thanks to satellites and the ISS we are able to keep track of reef health by looking from above.