The Great Barrier Reef extends for 2,000 kilometers along the
northeastern coast of Australia. It is not a single reef, but a vast
maze of reefs, passages, and coral cays (islands that are part of the
reef). This nadir true-color image was acquired by the Multi-angle
Imaging Spectroradiometer (MISR) instrument on August 26, 2000, and shows part of the southern
portion of the reef adjacent to the central Queensland coast. The width
of the MISR swath is approximately 380 kilometers, with the reef clearly
visible up to approximately 200 kilometers from the coast. It may be
difficult to see the myriad details in the browse image, but if you
retrieve the higher resolution version,
a zoomed display reveals the spectacular structure of the many reefs.
The more northerly coastal area in this image shows the vast extent of
sugar cane cultivation, this being the largest sugar producing area in
Australia, centered on the city of Mackay. Other industries in the area
include coal, cattle, dairying, timber, grain, seafood, and fruit. The
large island off the most northerly part of the coast visible in this
image is Whitsunday Island, with smaller islands and reefs extending
southeast, parallel to the coast. These include some of the better known
resort islands such as Hayman, Lindeman, Hamilton, and Brampton Islands.
Further south (in the high-resolution
version), just inland of the small semicircular bay near the right
of the image, is Rockhampton, the largest city along the central
Queensland coast, and the regional center for much of central
Queensland. Rockhampton is just north of the Tropic of Capricorn. Its
hinterland is a rich pastoral, agricultural, and mining region.
The Sudanese coast of the Red Sea is a well-known destination for diving due to clear water and abundance of coral reefs (or shia’ab in Arabic). Reefs are formed primarily from precipitation of calcium carbonate by corals. (In addition to its commonly used meaning, precipitation can also describe how something dissolved in a solution becomes “undissolved” through chemical or biological processes.) Massive reef structures are built over thousands of years of succeeding generations of coral. In the Red Sea, fringing reefs form on shallow shelves of less than 50 meters depth along the coastline. This astronaut photograph illustrates the intricate morphology of the reef system located along the coast between Port Sudan to the northwest and the Tokar River delta to the southeast.