Introduction to Coral Reefs

What are Corals?

• Corals are marine invertebrates, resembling plants but are actually soft-bodied animals called polyps.
• Polyps secrete a hard, protective skeleton of calcium carbonate, providing safety and forming a colony.
• A group of polyps acts as a single coral.
• Corals form large structures called coral reefs.

Conditions for Coral Reef Growth

• Corals thrive in tropical waters with temperatures between 21°C and 30°C.
• They are primarily found in shallow water, up to 45 meters deep, due to their need for sunlight.
• Clear water is essential for sunlight penetration and photosynthesis by symbiotic algae.
• Clean, oxygenated water is required to avoid pollution and provide adequate oxygen levels.
• Corals need a balanced salt-to-water ratio for their survival.

Reef Formation

• Coral larvae, free-swimming, attach to hard surfaces like rocks, marking the beginning of reef formation.
• Individual polyps secrete calcium carbonate skeletons, contributing to a living mat overtime.
• Over time, the accumulation of millions of calcium carbonate skeletons creates massive reefs.
• Other organisms, including algae, seaweed, sponges, mollusks, and sediments, also contribute to the reef structure.

Types of Coral Reefs

• Fringing reefs: Located near shorelines, directly bordering the coast.
• Atoll reefs: Ring-shaped structures that enclose a lagoon, formed by volcanic islands sinking below sea level.
• Barrier reefs: Found parallel to the mainland, separated by a deep channel or lagoon.