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Natural disasters pose threat to coral reefs

By Melanie J. Martin - 12 Sep 2011 18:12:0 GMT
Natural disasters pose threat to coral reefs

Ocean acidification isn't the only problem coral reefs are facing. Natural disasters like earthquakes can also harm these marine ecosystems. Researchers have found that in May of 2009, an earthquake in the west Caribbean destroyed half of the Belizean Barrier Reef lagoon's corals reefs. The 7.3-magnitude earthquake launched the lagoonal reefs into deeper waters, essentially causing a coral reef avalanche.

The Belizean Barrier Reef is the second largest reef ecosystem in the world, second only to Australia's Great Barrier Reef.

Prior to the earthquake, mass mortality events had dramatically altered the reef ecosystem over the course of 25 years. White band disease, a bacterial infection, had killed off the dominant staghorn coral.

Strikingly, this species had held dominance for almost 4,000 years. When El Nino brought high temperatures, the subsequent dominant species, lettuce coral, died off due to mass bleaching.

Researchers assert that those planning conservation methods must consider how natural disasters could affect an ecosystem. Although no one can predict exactly when disasters will occur, the possibility of disasters should play a role in determining factors like the size of the conservation area, researchers stress. In other words, preserving a larger area increases the likelihood that some of the ecosystem will survive natural disasters intact.

Disasters like hurricanes and tsunamis also place coral reef ecosystems at risk. These diverse ecosystems provide habitat for an abundant range of life.

Most existing reefs are between 5,000 and 10,000 years old, and like rainforests, they require copious amounts of time to reemerge in all their diversity. One generation of tiny polyps after another must live and die, leaving behind their limestone skeleton, for a reef to form.

Dramatic increases in natural disasters around the world put marine ecosystems at greater risk. Land ecosystems naturally face risks from unpredictable disasters too, so the same planning principles apply there.

Researcher Richard Aronson of the Florida Institute of Technology and his co-authors published these findings in the journal Ecology, of the Ecological Society of America.

Top Image Credit: The Barrier Reef in Belize the second largest in the World. © Ramunas