Coral Atolls

November 03, 2000

Atolls_hires

Provided by: NASA/GSFC
Summary authors & editors: Jim Foster

This is a Landsat-7 satellite image of coral atolls in the South Pacific, looking here like a string of pearls with hues of blue and green. Coral atolls surround lagoons and typically are products of volcanic islands that have nearly completely eroded away. The coral ring is the remnant of the volcano's crater. The structure and extent of coral reefs are now for the first time being monitored globally using Landsat-7 data. Reefs from about 900 locations around the world will be analyzed using different wavelenghts of light from the 30 m resolution Landsat-7 sensor. According to the Landsat Project Scientist, Darrel WIlliams, the ability to observe reefs worlwide and to archive the images is a valuable scientific resource. This is especially important now since many coral reefs around the globe are in stages of ecological collapse, and remote sensing can be usd to monitor their health and perhaps even provide clues as to the cause of their demise.

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