Thursday, February 18, 2010

Cold Erases Color

Coral colonies off the coast of the Florida keys were hit with so much cold recently, they turned white. It turns out, this idea is called "coral bleaching" and it occurs because of a major fluctuation in temperature. Between January 2nd and January 13th, the water temperatures around the keys were astonishingly lower than average. Normal winter averages for this area are somewhere between 18 and 23 degrees celsius. During this time, the temperature reached a low of 11 degrees celsius.
So where did the color go? Well, the beautiful coloration of coral comes from the algal organisms living on coral, creating a mosaic of colors depending on the algae species. So, when the temperature gets too cold, the algae die, leaving the coral a "bleach white" color. Not only did the cold snap affect the coral, many sea turtles and manatees reportedly died, along with an abundance of fish.
The recovery of a traumatic event such as this varies. Sometimes, the coral will make a complete, or almost complete recovery; however divers in this area are reportedly seeing many dead patches in the colonies.

The entire article can be found here


  1. Wow, this is really sad! I hope the coral and organisms recover! I had no idea coral "bleaching" could happen because of cold temperatures, but it makes sense.

  2. This is very unfortunate. Hopefully they make a full recovery and regain their color when summer comes around. I don't think i will make it to Australia to see the great barrier reefs, but Florida's reefs could be an option

  3. I would have liked to have seen the reefs as they were, hopefully one day they will be restored and in prefect condition.

  4. We will be covering coral reefs and their current sad state (in many parts of the world) at the end of the semester. I had not heard about these effects of cold weather, but it is also clear that increasing ocean temperatures are damaging corals around the world too.