CHAPEL HILL Corals in the central and western Pacific ocean are dying faster than previously thought, University of North Carolina at Chapel Hill researchers have found. Nearly 600 square miles of reef have disappeared per year since the late 1960s, twice the rate of rainforest loss.
The reefs are disappearing at a rate of one percent per year, a decline that began decades earlier than expected, the researchers discovered. Historically, coral cover, a measure of reef health, hovered around 50 percent. Today, only about 2 percent of reefs in the Indo-Pacific have coral cover close to the historical baseline
We have already lost half of the worlds reef-building corals, said John Bruno, lead study author and associate professor of marine ecology and conservation in the department of marine sciences in UNC-Chapel Hills College of Arts and Sciences.
The results were published Aug. 8, 2007, in the online journal PLoS One. The study provides the first regional-scale and long-term analysis of coral loss in the region, where relatively little was known about patterns of reef loss.
The Indo-Pacific contains 75 percent of the worlds coral reefs and has the highest coral diversity in the world. High coral cover reefs in the Indo-Pacific ocean were common until a few decades ago, the researchers found.
Bruno and Elizabeth Selig, a graduate student in the College of Arts and Sciences curriculum in ecology, compiled and analyzed a database of 6,000 quantitative surveys performed between 1968 and 2004 of more than 2,600 Indo-Pacific coral reefs. The surveys tallied coral cover, a measure of the ocean floor area covered by living corals. Scientists rely on coral cover as a key indicator of reef habitat quality and quantity, similar to measuring an area covered by tree canopy as a gauge of tropical forest loss.
Coral cover declined from 40 percent in the early 1980s to approximately 20 percent by 2003, the research
Contact: Becky Oskin
University of North Carolina at Chapel Hill