Coral is an example of symbiotic relationship between coral polyps and __________. 

The correct answer is Zooxanthellae.

Key Points

• Coral is an example of a symbiotic relationship between coral polyps (animals) and zooxanthellae (photosynthetic algae).
• Zooxanthellae live within the tissues of coral polyps and provide them with energy through the process of photosynthesis.
• In return, coral polyps provide the zooxanthellae with a protected environment and the compounds needed for photosynthesis, such as carbon dioxide and nutrients.
• This relationship is essential for the survival of coral reefs, as it helps corals build their calcium carbonate skeletons and thrive in nutrient-poor marine environments.
• When stressed (e.g., due to warming seas or pollution), corals can expel zooxanthellae, leading to a phenomenon called coral bleaching, which can cause the death of coral reefs.

Additional Information

• Coral Reefs:
  • Coral reefs are marine ecosystems characterized by their high biodiversity and are often referred to as the "rainforests of the sea."
  • They provide habitat for about 25% of all marine species, despite covering less than 1% of the ocean floor.
  • Coral reefs act as natural barriers, protecting coastlines from waves, storms, and erosion.
• Zooxanthellae:
  • These are a type of dinoflagellates (unicellular algae) that live in a mutualistic relationship with corals.
  • They give corals their vibrant colors due to the pigments used during photosynthesis.
  • The energy provided by zooxanthellae allows corals to grow and reproduce efficiently in nutrient-deficient waters.
• Coral Bleaching:
  • Coral bleaching occurs when corals expel their zooxanthellae due to stress caused by factors like increased sea temperatures, pollution, or ocean acidification.
  • Without zooxanthellae, corals lose their color and their primary source of energy, which often leads to their death.
• Importance of Coral Reefs:
  • Coral reefs support fisheries, tourism, and coastal protection, contributing significantly to the global economy.
  • They also play a critical role in carbon and nitrogen cycling in marine ecosystems.
• Threats to Coral Reefs:
  • Major threats include climate change, ocean acidification, overfishing, destructive fishing practices, pollution, and sedimentation.
  • Global initiatives like the Coral Triangle Initiative and local conservation efforts aim to protect and restore coral reef ecosystems.