Anyone who has strapped on diving gear and glided past a healthy
coral reef knows that few sights in nature are as breathtaking. From the
intricately embroidered patchwork of the corals themselves to the myriad
of multicolored creatures that live in the reefs crevices to the
shimmering schools of fish that seem to move as one, every cubic inch of
a thriving coral habitat appears to be alive and teaming with
complexity. In truth, coral reef habitats represent some of the densest
and most varied ecosystems on Earth. Though they cover only 0.2 percent
of the oceans floor, scientists estimate that nearly one million
species of fish, invertebrates, and algae can be found in and around the
While reef habitats appear to be robust enough to withstand almost anything, they are extremely fragile. Not only are most corals brittle, but they usually need pristine, clear, warm, relatively nutrient-free waters to survive. Over the past 50 years, humans have put an enormous amount of pressure on coral reef environments by altering their waters and tearing up their foundations. From dynamite fishing to global warming, we are rapidly sending the worlds reefs into oblivion. The latest reports state that as much as 27 percent of monitored reef formations have been lost and as much as 32 percent are at risk of being lost within the next 32 years.
For marine biologists, the destruction of the reefs has proven to be
as frustrating as it is heartbreaking. Because reef habitats are so
complex, and because worldwide reef monitoring and mapping efforts only
began a little over a decade ago, scientists simply do not have enough
information to keep tabs on the destruction of the reefs, let alone come
up with an effective solution. At the rate the reefs are disappearing,
they may be beyond repair by the time a comprehensive plan to save reefs
can be put into place.
|Coral reefs rival the tropical rainforests as the most diverse ecosystems on Earth. With a wide variey of plant, animal, and microbial life, they are not only beautiful destination for divers, but an important indicator of ocean health. (Photograph copyright Corel Corporation)|
Scientists at NASAs Goddard Space Flight Center and at several universities around the world, however, may have at least a partial solution to this problem. They have been examining detailed images of the ocean collected by the Landsat 7 and other high-resolution remote sensing satellites. While these types of satellites were primarily launched to observe land-based change, they have also been found to produce detailed images of shallow waters around the oceans margins. Using these images, the scientists have been able to map reefs in a fraction of the time it takes to map them by boat or airplane. With funding, the researchers believe they could have a comprehensive map of the worlds reefs within three years. This map would not only be useful for identifying large-scale threats to the reefs, but would allow the researchers to locate those reefs that are in the most trouble.
Tuanake Atoll in French Polynesia is one of many of the remote reefs recently mapped with the help of satellite data. This true-color image was acquired by Landsat 7. (Image courtesy Serge Andrefouet, University of South Florida)