Part 9: Do coral reefs recover from oil spills?

Corals are long-lived and recover slowly from disturbances, whether these are natural, such as hurricanes, or human-caused, such as ship groundings or exposure to pollutants. How fast and how well a coral reef recovers depends on the extent and type of damage, the location, species affected, available habitat suitable for coral colonization, and many other parameters. Severe and repeated impacts delay recovery, while ongoing pollution and other chronic stresses may postpone it indefinitely.

Coral on damaged reefs recover by regenerating from partially damaged colonies, by reestablishing broken coral fragments, and through settlement of coral larvae carried by ocean currents.

Coral communities may recover more rapidly from oil exposure alone than from mechanical damage. Recovery of coral reefs after oil exposure, however, may depend partly on the recovery of associated communities that may be more seriously affected, such as mangroves and seagrass beds.

A physically damaged reef recovers more slowly, and may need restoration. For example, vessel groundings fragment coral skeletons, producing loose rubble and fine sediments that inhibit successful recolonization of hard corals.

Recovery time depends on the type and intensity of the disturbance and can range from several years for localized and small-scale disturbances, to decades or centuries for severe impacts.