5 Minutes of science- Coral Bleaching

Coral, contrary to popular belief, is an animal. It is composed of coral polyps, small organisms, no larger than the thickness of a nickel. It is involved in a symbiotic relationship with a special kind of algae, called zooxanthellae. Coral keeps the algae safe, and in return the algae provides it with oxygen.

When coral is under high stress, it expels the algae from its tissue. The algae is corals source of vibrant color, so when it is removed the coral appears white like it was dipped in bleach.The main sources of this stress are, changes in water temperature, Pollution, Runoff water, Exposure to air during low tide, exposure to too much sun light. 

Coral bleaching is a common event, mass bleaching events have happened over the years. the largest on record happened in 2002 at the great barrier reef, where 54% of the coral was bleached. Bleaching is referred to as "The beautiful death" because it looks nice, but there is a higher mortality rate in effected corals. An easy way to prevent/fix coral bleaching is to treat the enviornment better. Many factors that harm the coral are man made. 

Currently the norther part of the great barrier reef is experiencing a bleaching event due to a 1 degree celsius change in the water temperature. Many were quick to say the reef was dead but its not too late, coral is a hearty life form and is known to bounce back from what seem to be extinction events. 

sources-

http://oceanservice.noaa.gov/facts/coral.html


http://oceanservice.noaa.gov/facts/coral_bleach.html


http://www.gbrmpa.gov.au/media-room/coral-bleaching


 

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