coral reefs & bleaching

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  • 1.SC-249 Environmental Concepts & IssuesTaichi Kikuchi

2. Outline1.What is Coral Reef?2.What is Coral Animal?3.Type of corals4.Phylum: Cnidaria5.The symbiotic relationship6.What is Coral Bleaching?7.Why do we have to care about Corals?8.How can we protect Corals from bleaching?9.Projects to survey and protect Corals10. References 3. What is Coral Reef? The coral reef is a unique shallow water community oforganisms living on limestone rock that was built bysome of the reef organisms (Lerman 426). The main reef builders are corals and coralline algae. Marine organisms that secrete calcium carbonate suchas clams, snails and sponges accumulate to form reefsafter their death. In other words, a reef is a clump of calcareous rockderived from diverse organisms living on the reef. 4. What is Coral Animal? Phylum : Cnidaria (same group as jelly fish, seaanemone) Corals inhabit in shallow, clear water within tropics. They have symbiotic tiny algae (zooxanthellae) withinthe body. In the daytime, they get nutrition via photosynthesisby zooxanthellae. They hunt for food at night with their tentacles. There are 215 scleractinian (58 genera) and 7 non-scleractinian corals in Palau (PICRC 12). 5. Type of corals Solitary (mushroom coral)/ colonial corals Stony corals: brain, staghorn, antler, lettuce, andflower coral They secrete a cup-shaped skeleton of calciumcarbonate, called corallite. Soft corals(octocorallia): seafans, sea pens, whip coralsThey secrete soft, flexible skeletons made of keratin. Abundant stony corals in Pacific reefs. Abundant soft corals in Caribbean reefs. 6. Phylum: Cnidaria The classification of the major groups of coral animals 7. The symbiotic relationship Corals excrete their wastes to tiny algae. The tiny algae produce nutrition for coral polyps. 8. What is Coral Bleaching? Coral Bleaching = Corals which lost their symbioticalgae appear whitish. Corals are compelled to expel the algae because of itstoxin when they are under stressful condition. Unusual high water temperature is thought as themain cause of the mass bleaching event in 1997~98. Some species can survive bleaching but the aftereffectincludes slower growth, fragile body and higher risk ofdisease. 9. Why do we have to care aboutCorals? Ecological value: corals sustain rich marine biodiversity.(ex. Shelter for some animals, food for other animals Economical value: tourism, fishery industry(ex. Divers, tourists, and food supply Environmental value: they provide protection for us.(ex. Breaking storm wave, tsunami, typhoon Coral reefs have a great importance for Palau in manyaspects. 10. How can we protect Corals frombleaching? Not to touch corals physically. Stop destructive actions such as dynamite fishing, overcoastal development causing sedimentation. Have an interest on coral reef and take actions tospread knowledge. Proper instruction for any people trying to play aroundcoral reefs. 11. Projects to survey and protectCorals The Marine Protected Areas (MPAs) = the place where people are prohibited or restricted to enter and use resources. PICRC National Long-Term Coral Reef Monitoring Program in 200121 monitoring sites around the main islandsCoral reefs are recovering for 3 years from 2001.It suggests that some species are more resistant to pressure. 12. ReferencesMarshall, P and Schuttenberg, H. A Reef Managers Guide to Coral Bleaching. Townsville: Great Barrier Reef Marine Park Authority, 2006.Lerman, M. Chapter 13 Coral Reefs. Marine Biology. California:The Benjamin/Cummings Publishing Company, Inc, 1986.Palau International Coral Reef Center, and Japan InternationalCooperation Agency. Coral Reefs of Palau. Palau: PalauInternational Coral Reef Center, 2007.