PROTECTING A NATIONAL TREASURE: A REEF MANAGER’S GUIDE TO CORAL BLEACHING

Coral reefs form the foundation for multi-million dollar industries. Many coastal communities rely on them for eco-tourism, fishing, and shoreline protection from erosion and storm damage. Also, they are the backbone to an entire ecosystem. Corals are primary producers and support a diverse community that lives on and around the reef. However, coral reefs are threatened by pollution, sedimentation, over fishing, disease, habitat destruction and coral bleaching. Over the past decade, scientists have seen a marked increase in the amount and scale of coral bleaching events. Coral bleaching is caused when the colorful algae that live inside the coral polyps are expelled after having been damaged, which causes the coral to look bleached. Coral bleaching can be caused by many different stress factors, but recently mass bleaching events, which are those occurring over a large geographic area, have been attributed to rising sea surface temperatures, an event associated with climate change affects. During and after these events, the corals will either recover or die.

Published in 2006, the National Oceanic and Atmospheric Administration’s “A Reef Manager’s Guide to Coral Bleaching” is designed to help predict, assess, and mitigate the effects of coral bleaching. Jordan West, Special Assistant for Ecology in EPA’s National Center for Environmental Assessment, played a large role in developing the Guide. Her work focuses mainly on understanding natural patterns of resistance and resilience in the face of coral bleaching. Some factors that contribute to bleaching resistance and post-bleaching recovery (resilience) are cooler water from upwelling, rapid currents that flush toxins, shading of light by cliffs or shelves, turbid water that blocks light, and conditions conducive to coral recolonization. With such information on why some corals resist and why some reefs more quickly recover from bleaching events, managers can take steps to appropriately protect the most climate-resilient reefs from direct human impacts that can be controlled at a local level. Limiting local stressors, such as over fishing, pollution and damage from recreational uses can be an immediate way for managers to further boost the resilience of coral reefs and help them persist in a changing climate.

Coral reefs that are resistant to bleaching events and sustain a healthy ecosystem will promote socioeconomic wealth for the communities that rely on them. For more information on ecological effects of climate change visit our Web site at Collaborative Guide: A Reef Manager's Guide to Coral Bleaching