Tropical Coral Reefs

• Ecological features

  • Coral nutrition - Cilia, Nematocysts, Symbiotic algae e.g. zooxanthellae
  • Reef building corals - many species secrete a limestone base which continually added to building a reef
  • Abiotic conditions - light, temperature, immersion, turbidity, salinity
• Importance

  • Fisheries
  • Medicinal discoveries
  • Climate control
  • Erosion protection
  • Tourism
• Threats 


  • Physical damage - hard objects can kill polyps
  • Collection of ornaments - many species in coral reefs are collected to be sold as ornaments
  • Sedimentation - turbid water covers corals and stops them photosynthesizing
  • Pollution - pollutants can harm coral reefs
  • Coral bleaching - symbiotic algae is killed
  • Introduced species - non-indigenous species out compete indigenous ones
  • Fishing - over-fishing
  • Coastal developments - expansion of coastal towns can increase turbidity
  • Loss of associated habitats - mangroves and seagrass that protect coral reefs
• Conservation Efforts

  • Marine Protected Areas e.g. the great barrier reef
  • Control of fishing - fishing for over-exploited species can be banned to allow the population to recover
  • Control of tourism - restriction of recreational activities to minimize the damage that may be caused e.g. banning of spear fishing and collection of souvenirs
  • Sustainable Exploitation
  • Reef creation - artificial reefs by purposefully sinking old ships and oil rigs