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

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

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

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

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

Global Coral Reefs

Coral Bleaching Hotspots

Global Sea Surface Temperatures

Areas affected before mass bleaching event of 1998 Degree of bleaching:red – highyellow – medium blue – lowgreen - none

Areas affected after mass bleaching event of 1998 Degree of bleaching:red – highyellow – medium blue – lowgreen - none

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