Coral Faces Second Mass Die-Off

The weather has been rough this year.  Hurricanes, rough winter and extreme summer heat.  that extreme summer heat has caused more issues than just high electricity bills from running the air conditioner.  The world's coral reefs have come under severe stress and scientists fear they are in danger of dying off.

The heat is causing the coral to shed its color, or bleach.  Many corals have already expired and the dying isn't stopping now.  Warm water in the Caribbean could cause coral there to undergo drastic bleaching within the next few weeks.

This is the second time coral has undergone a mass die-off.  In 1998, some 16% of the world's shallow-water reefs died.  However, scientists fear that in some areas, such as Thailand, the die-off this year will be worse than that of 1998.

Record high temperatures for the first eight months of 2010 have increased ocean temperatures which, in turn, placed stress on the delicate corals.  Not only do corals add a breathtaking beauty to the landscape of the ocean, they provide a natural habitat for a variety of sea creatures.

The reefs themselves are millions of tiny polyps working hand-in-hand with algae.  The algae capture sunlight and carbon dioxide and feed the polyps.  It is the algae that bring the beautiful and vivid colors to the reefs.  When temperatures rise, the metabolism of the algae speeds up and they create toxins rather than sugars to feed the polyps.  The polyps reject the algae and bleaching occurs.  The corals can possibly recover if temperatures drop to where the algae can reproduce.  Continued heat eventually kills the polyps.

Some areas appear to be slowly recovering as temperatures slowly drop and some areas appear to not have been affected at all.  The reefs of the Florida Keys have yet to suffer any effects of bleaching while serious bleaching has happened off the Texas-Louisiana border.  The north Caribbean has experienced initial bleaching but are now experiencing cooler temperatures thanks to hurricanes and tropical storms.  The southern Caribbean hasn't been so lucky.

The most famous coral reef in the world, Australia's Great Barrier Reef has many scientists worried.  The Australian summer is just beginning and Australian waters are already above normal temperatures.  The worry is if there is a bad monsoon season, the Great Barrier Reef will sustain serious bleaching.

Source:  http://www.msnbc.msn.com/id/39282717/ns/technology_and_science-the_new_york_times/