Coral reefs have been suffering damage due to which combination of factors?

• A. Increasing ocean temperatures, sediment runoff, destructive fishing practices
• B. Rising sea levels alone
• C. Invasive species only
• D. Pollution from cruise ships

Answer: (A)

Coral reef decline is driven by several stressors that interact and amplify each other. Warmer ocean temperatures cause bleaching, where corals expel the symbiotic algae they rely on for energy, making them more vulnerable and less able to recover if heat stress continues. Sediment runoff clouding the water reduces light essential for the corals’ algae and can physically smother delicate tissues, slowing growth and healing. Destructive fishing practices, such as methods that damage the reef or remove key herbivores, disrupt the reef’s balance and allow algae to overgrow, which competes with and hinders coral recovery.

When these factors occur together, they create a compounded assault: heat stress weakens corals, poor water quality and light reduction impede growth, and loss of ecological balance from fishing pressure prevents the reef from bouncing back. This combination best explains the widespread damage seen in many reefs.

Rising sea levels alone don’t directly cause the widespread bleaching and mortality observed; invasive species and pollution from cruise ships are concerns but don’t on their own capture the same multi-factor, synergistic impact that warming, sedimentation, and destructive fishing do.