How are coral reefs faring around the world?

How are coral reefs faring around the world?

—Debby Greco, Canton, CT

Not so well, unfortunately. Research experts from the World Resources Institute, a Washington, DC-based organization of scientists, economists and policy experts, report that coral reefs around the world are dying or disappearing at an alarming rate.

Lining 60,000 miles of shoreline along 109 countries, reefs and their related fisheries, marshlands and lagoons are home to more than a quarter of all fish species on Earth. An estimated 25 percent of coral reefs have already disappeared and an estimated 67 percent of all remaining coral reefs are endangered today. In Southeast Asia, 88 percent of the reefs are at risk. In the U.S. Florida Keys, more than 90 percent of the reefs have lost their living coral cover since 1975.

According to the Planetary Coral Reef Foundation, which monitors the health of coral reefs worldwide and coordinates an international “Save the Reefs Campaign,” the greatest threat to coral reefs thus far has been the coastal development resulting from human population expansion. Over the last 30 years, this trend has profoundly increased the amount of freshwater “runoff” into costal areas. Known collectively as “non-point source pollution,” this runoff has carried with it large amounts of sediment, sewage and chemicals from land-clearing areas, agricultural areas and septic systems into the reefs. The resulting pollution of the water thus decreases the amount of light reaching the corals, choking the life out of these fragile structures.

Meanwhile, increases in both commercial and sport fishing, enhanced by ever-improving technologies, have also taken a toll on reef health by removing so many of the large fish, which when healthy and plentiful keep fragile reef ecosystems in balance.

Moving forward, scientists studying coral health are most concerned about the impacts of a somewhat newer threat: climate change. Indeed, global warming is changing the surface temperatures of ocean waters faster than corals can adapt. “Coral reefs are so sensitive to temperature change that it seems inevitable that many will die as a result of global warming as well as all the other terrible things that are happening to them,” says Rod Fujita, a marine biologist with Environmental Defense, a non-profit advocacy group. Furthermore, coral reefs” very sensitivity to environmental changes makes them a “canary in a coal mine” early warning system with regard to the overall declining health of the world’s oceans.

Meanwhile, the non-profit Coral Reef Alliance is working toward the establishment of a comprehensive global map of living coral reefs to serve as a baseline for learning how fast we are losing them and how we can stem the decline. Also, a new program by the National Aeronautics and Space Administration (NASA) is monitoring coral reefs by satellite to try to put some of the puzzle pieces together.

CONTACTS: World Resources Institute, www.wri.org ; Planetary Coral Reef Foundation, www.pcrf.org ; Environmental Defense, www.environmentaldefense.org ; Coral Reef Alliance, www.coralreefalliance.org ; National Aeronautics and Space Administration (NASA), www.nasa.gov.