Coral Bleaching

1. Coral Bleaching Chrissy Covington October 14, 2004 Introduction to Coastal Management Dr. Hosier & Dr. Cleary

2. Basic Anatomy of Corals • Coral polyp – sessile organism, deposits a calcium carbonate cup around itself • Coral heads – collection of calcified polyps, cemented together by coralline algae • Coral reef – collection of coral heads

3. Corals & Zooxanthellae Corals provide zooxanthellae: secure home steady supply of carbon dioxide Zooxanthellae provide corals: fixed carbon compounds for energy enhanced calcification nutrients coloration

4. Coral Bleaching • Loss of color from corals • Results from loss of zooxanthellae or loss of pigments from zooxanthellae • Corals lose 60-90% of their zooxanthellae, each zooxanthella loses 50-80% of its pigment

5. Causes of Bleaching • Increased sea surface temperatures, due to global warming • Human disturbances • Sedimentation • Coastal pollution • Sudden exposure

6. Global Coral Reefs

7. Coral Bleaching Hotspots

8. Global Sea Surface Temperatures

9. Areas affected before mass bleaching event of 1998 Degree of bleaching: red – high yellow – medium blue – low green - none

10. Areas affected after mass bleaching event of 1998 Degree of bleaching: red – high yellow – medium blue – low green - none

11. Conclusion • Coral bleaching most likely caused by effects of global warming • Only solution is to combat global warming by reducing greenhouse gas emissions