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  • 1. Threats to Coral Reefs Natural and Human
  • 2. Where Can You Find Coral Reefs?  Coral is found all over the world:  Tropical  Temperate  Polar Coral reefs around the world  Only tropical corals build reefs
  • 3. Coral reefs around the world
  • 4. REEFS WORLDWIDE ARE THREATENED• 11% of reefs have been lost• 16% of reefs severely damaged• ~60% of studied reefs threatened by human activities• No pristine reefs left
  • 5. Threats to coral and coral reefs: • 1) Natural • 2) Anthropogenic –of human origin
  • 6. Natural disturbances that affect corals and coral reefs? • Hurricanes • Tsunamis • Volcanoes • Earthquakes • Predators & competitors • Bleaching • Pathogens
  • 7. Hurricanes• Physical damage• Smothering• Freshwater poisoning• Destruction of other ecosystems upon which coral reefs depend
  • 8. Tsunamis• Physical damage• Erosion• Possible disruption of reproduction and recruitment
  • 9. Volcanoes• Depends upon where volcano occurs• Heat• Smothering and sedimentation
  • 10. Earthquakes• Little direct impact• Indirect impacts -triggers tsunamis -coastal landslides
  • 11. Predators• crown of thorns starfish• snails• parrotfish• butterflyfish
  • 12. Crown of Thorns Starfish
  • 13. Coral-eating Snails
  • 14. Competitors • algae
  • 15. • Loss of zooxanthellae• causes – higher than usual ocean temperature – sharp changes in salinity – heavy UV light exposure
  • 16. Pathogens• Diseases on the rise – new pathogens (8+) – land pathogens (Aspergillus) – occurring at all depths – More susceptible when stressed
  • 17. Threats from Nature• Unusually strong waves such as those from a hurricane• Water temperature changes• Dramatic changes in saltiness of water• Predators, such as snails and crown of thorns starfish• Overgrowth of algae
  • 18. Threats to coral and coral reefs: • 1) Natural • 2) Anthropogenic –of human origin
  • 19. Anthropogenic threats to coral reefs:• Overfishing• Development• Mining and dredging• Recreation
  • 20. Overfishing• Ecological imbalance
  • 21. Overfishing• Ecological imbalance
  • 22. Overfishing• Destructive fishing practices
  • 23. Development• Sediment smothering• Freshwater input• Pollutants & nutrients (sewage, pesticides, fertilizer, heavy metals, pathogens)
  • 24. Development
  • 25. Development
  • 26. Pollution
  • 27. Power Plants
  • 28. Mining for construction materials and dredging• Destruction of reef structure• Stirs up sediment
  • 29. RecreationAnchors, boats, flippers, hands, feet•Kill animal tissue•Skeleton breakage
  • 30. Threats from Humans• Pollution – Sediments block light from zooxanthellae – Chemicals either poison corals or allow too much algae to grow• Power plants – Filter water and kill fish and plankton – Releasing hot water kills organisms
  • 31. More Threats from Humans• Deforestation – Causes erosion which clouds the water – Burning of trees could be a factor in climate change• Destructive fishing – Blasting with dynamite – Cyanide poison – Boats running aground, anchors – Overfishing
  • 32. Synergistic effects• interaction of natural changes & human activity• multiple insults
  • 33. Global climate change• Reduced reef building• Increase in frequency and intensity of hurricanes• Increases in bleaching• Increased in disease
  • 34. A New Home• Corals now have a choice of where to live• Corals are very sensitive and are rapidly dying• People are trying to help by creating artificial reefs
  • 35. Arguments for Artificial Reefs• It can help build or rebuild a reef• It will increase fish populations by making new habitats
  • 36. Arguments Against Artificial Reefs• Moveable• Chemical leaking and leaching into the ocean• It does not increase fish populations but rather moves them to one location away from their natural habitat which makes them easier to catch
  • 37. The Great Barrier Reef
  • 38. Tubbataha Reef
  • 39. It’s up to Us to Save Coral Reefs Be Responsible.