Which statement best describes the role of coral reefs in coastal protection and the effect of warming oceans?

• A. : They amplify wave energy, increasing coastal erosion; warming has no impact.
• B. They trap sediment, reducing water clarity but increasing coastal protection.
• C. They dissipate wave energy and reduce coastal erosion; warming causes bleaching, disease, and structural loss, reducing protection and biodiversity.
• D. They increase biodiversity but do not affect shoreline protection.

Answer: (C)

Coral reefs act as offshore breakwaters. Their complex, rigid structure disrupts and slows incoming waves, so much of the wave energy is dissipated before it reaches the shoreline. That damping effect reduces coastal erosion and the potential damage to shores and coastal infrastructure.

When oceans warm, corals undergo bleaching because their symbiotic algae are expelled under heat stress; prolonged warming also raises disease risk and can cause skeletal degradation. As reef health declines, its ability to dissipate wave energy diminishes, meaning more wave energy reaches the coast and erosion risk increases. At the same time, the loss of habitat reduces biodiversity.

So the statement that describes reefs as dissipating wave energy and protecting shorelines, while warming causes bleaching, disease, and structural loss that reduce protection and biodiversity, best fits what actually happens.