A Coral Catastrophe? (broadcast Friday, July 11th, 2008)

Bleached corals on coral reef on southern Great Barrier Reef in January 2002. Coral bleaching primarily affects reef building corals when conditions get too warm. Image © Science

A third of the world's reef-building coral species are vulnerable to extinction, researchers report this week in the journal Science. An international team of researchers surveyed over 700 species of coral around the world and found that over 230 of them should be classified as "Critically Endangered," "Endangered," or "Vulnerable" to extinction. Coral reefs are threatened by environmental issues such as fishing operations and oil exploration -- but the largest threat to the reefs are climate change and carbon dioxide levels. Warmer water temperatures lead to a condition known as 'coral bleaching,' which results in white, dead coral skeletons where once there were thriving reef communities. Increased carbon dioxide levels acidify the ocean water, making it harder for corals to build their calcium-based skeletons. We'll talk with one of the authors of the report about the plight of corals, and whether anything can be done to turn back the tide. Teachers, find more information about using Science Friday as a classroom resource in the Kids' Connection.