Greggy

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Greggy

  1. 1. Threats to Coral Reefs Natural and Human
  2. 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. 3. Coral reefs around the world
  4. 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. 5. Threats to coral and coral reefs: • 1) Natural • 2) Anthropogenic –of human origin
  6. 6. Natural disturbances that affect corals and coral reefs? • Hurricanes • Tsunamis • Volcanoes • Earthquakes • Predators & competitors • Bleaching • Pathogens
  7. 7. Hurricanes• Physical damage• Smothering• Freshwater poisoning• Destruction of other ecosystems upon which coral reefs depend
  8. 8. Tsunamis• Physical damage• Erosion• Possible disruption of reproduction and recruitment
  9. 9. Volcanoes• Depends upon where volcano occurs• Heat• Smothering and sedimentation
  10. 10. Earthquakes• Little direct impact• Indirect impacts -triggers tsunamis -coastal landslides
  11. 11. Predators• crown of thorns starfish• snails• parrotfish• butterflyfish
  12. 12. Crown of Thorns Starfish
  13. 13. Coral-eating Snails
  14. 14. Competitors • algae
  15. 15. • Loss of zooxanthellae• causes – higher than usual ocean temperature – sharp changes in salinity – heavy UV light exposure
  16. 16. Pathogens• Diseases on the rise – new pathogens (8+) – land pathogens (Aspergillus) – occurring at all depths – More susceptible when stressed
  17. 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. 18. Threats to coral and coral reefs: • 1) Natural • 2) Anthropogenic –of human origin
  19. 19. Anthropogenic threats to coral reefs:• Overfishing• Development• Mining and dredging• Recreation
  20. 20. Overfishing• Ecological imbalance
  21. 21. Overfishing• Ecological imbalance
  22. 22. Overfishing• Destructive fishing practices
  23. 23. Development• Sediment smothering• Freshwater input• Pollutants & nutrients (sewage, pesticides, fertilizer, heavy metals, pathogens)
  24. 24. Development
  25. 25. Development
  26. 26. Pollution
  27. 27. Power Plants
  28. 28. Mining for construction materials and dredging• Destruction of reef structure• Stirs up sediment
  29. 29. RecreationAnchors, boats, flippers, hands, feet•Kill animal tissue•Skeleton breakage
  30. 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. 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. 32. Synergistic effects• interaction of natural changes & human activity• multiple insults
  33. 33. Global climate change• Reduced reef building• Increase in frequency and intensity of hurricanes• Increases in bleaching• Increased in disease
  34. 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. 35. Arguments for Artificial Reefs• It can help build or rebuild a reef• It will increase fish populations by making new habitats
  36. 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. 37. The Great Barrier Reef
  38. 38. Tubbataha Reef
  39. 39. It’s up to Us to Save Coral Reefs Be Responsible.

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