April 6, 2006

NASA Helps Researchers Study Recent Coral Bleaching at Great Barrier Reef

(RedOrbit) Scientists have been working hard to understand the environmental conditions causing the widespread coral bleaching in Australia's Great Barrier Reef and it's subsequent effects on the global ecology. This work is being aided by NASA satellites which provide scientists with near-real-time sea surface temperature and ocean color data.

Australia's Great Barrier Reef is the largest and most complex system of reefs in the world made up of 2,900 reefs spanning over 600 continental islands and is considered by scientists to be center of the world's marine biodiversity. In addition to contributing to marine biodiversity, coral reefs also have an effect on human welfare, climate, and economics.

The vivid color of coral, caused by the tiny algae that associate with and help the coral thrive, is a reflection of the health of a coral reef. In addition to ocean "color" scientists also use ocean temperatures as an indication of what is happening with coral as coral are very temperature sensitive. Coral bleaching occurs when warmer than tolerable temperatures force corals to cast out the tiny algae, thus turning white and eventually dying.

According to oceanographer Gene Carl Feldman of the Ocean Biology Processing Group at NASA's Goddard Space Flight Center, Greenbelt, MD, "Coral, which can only live within a very narrow range of environmental conditions, are extremely sensitive to small shifts in the environment. Like the 'canary in the coalmine,' coral can provide an early warning of potentially dangerous things to come."

Researchers such as Scarla Weeks of the University of Queensland, Australia, are using data captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA's Terra and Aqua satellites to observe changes in sea surface temperatures and ocean primary productivity along the Great Barrier Reef and surrounding waters. They have observed that recent dramatic increases in sea surface temperatures are not only disrupting the relationship between corals and the algae that live within them but also affecting other marine creatures such as sea birds.

"After the high sea surface temperatures in 2002 caused the unprecedented bleaching incident, we saw a devastating reproductive failure in sea birds. The adult birds ultimately abandoned their nests resulting in a population loss in an animal vital to the marine ecosystem," said Weeks.

According to Feldman, "rising ocean temperatures are just one of the ever-increasing number of environmental stresses faced by coral reefs in general and the Great Barrier Reef in particular. With this distribution service, we're sharing NASA's unique ability to monitor our home planet from the vantage point of space and to provide scientists with the best and most timely information to carry out their research."

By Karen Ventii of RedOrbit from Wire reports

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