Sunday, October 17, 2010

Coral Bleaching in the Caribbean Basin

For those of you that venture into the marine realm you may have noticed something different about our reefs this year.  That is the reefs around Puerto Rico and throughout the Caribbean basin including the Gulf of Mexico are experiencing a bleaching event.  It is extremely hard to predict what is going to transpire with this event and overall scientists haven't determined whether or not it will be worse than the massive event in 2005.  During 2005, heightened sea surface temperatures for an extended period of the year lead to significant bleaching amongst many different species of corals in the Caribbean sea.  Coral bleaching can be defined as coral polyps that have lost their symbiont algae aka zooxanthellae that live within the polyp.  The pigments in the zooxanthellae are what give corals their different colors, therefore when the algae are absent from the polyps the corals turn white and are rendered more or less dormant until zooxanthellae can re-populate the polyps (if/when depending on the environmental stresses).  There are many unknowns related to bleaching.  For example, what species are more susceptible i.e. deep corals vs. shallow corals?...are the affects of  bleaching dependent upon morphology and level of arrangement of the polyps?  Does the polyp rid the algae or does the algae rid itself from the polyp?  These are many of the questions many scientists around the world are looking into answering.

A bleached boulder brain coral colony in the Tres Palmas Marine Reserve taken on October 17th 2010.

  This is another example of a bleached coral colony (massive starlet coral) with still some zooxanthellae held within some polyps (darker areas).  This photo was taken at Turromote in La Parguera on October 14th 2010.