Coral Reef Crisis Could Signal Threat to Maine Marine Life and Fisheries

ORONO — A rise in the temperature and acidity of the oceans that threatens the existence of the world’s coral reef ecosystems could also have troubling implications for marine life and fishing industries as far away as Maine, a University of Maine researcher says.

Robert Steneck, a professor at the School of Marine Sciences, is one of several authors of a new study predicting that increasing concentrations of carbon dioxide in the atmosphere, if not abated, will continue to deteriorate coral reefs to the point where they are likely to disappear altogether in the next few decades.

The potential collapse of these most biologically diverse and economically important ecosystems suggests a global atmospheric crisis that, Steneck says, could seriously harm fisheries around the world.

“The Carbon Crisis: Coral Reefs Under Rapid Climate Change and Ocean Acidification,” which represents the work of scientists from around the world, was published Dec. 14 in the journal Science.

“While we are far from where coral reefs live, I think it’s important to consider what this might mean in Maine,” says Steneck, who is based at the Darling Marine Center in Walpole. “It’s not as if coral reefs are on a different planet with a different atmosphere. They may be the canary in the mineshaft Earth, and the canary ain’t doing so swell these days.”

Scientists estimate that 25 percent of the world’s coral reefs are already gone or severely damaged and that another third are degraded and threatened. Rapid increases in carbon dioxide emissions, which in the 20th century have raised the average temperature of the world’s oceans by more than one degree Fahrenheit, “may be the final insult to these ecosystems,” the study states.

The acidity caused when carbon dioxide and water combine to make carbonic acid reduces the availability of calcium carbonate, or limestone, in the sea. Coral reefs are made of limestone, and lobsters, sea urchins, clams and scallops need it to calcify the hard parts of their bodies. Pteropods, a small, swimming organism with shells inside their bodies, are a major food source for Atlantic salmon. Yet, Steneck says, there is evidence that their shells, which the organisms can’t live without, are already eroding.

Reduced carbonates in the ocean are forcing creatures to spend more energy making their shells, which places them under greater stress. Steneck says about 30 new stress-induced coral pathogens have been identified in the last decade or so.

“And in Maine, anything that stresses shell-producers makes them more susceptible to disease,” he says. “In Rhode Island in 1998 there was a large-scale die-off of lobsters. If the same thing happened in Maine, where lobsters represent 85 percent of all marine resource value, it would threaten the socio-economic fabric along the entire coast.”

While some marine organisms have shown they can adapt to warmer temperatures, Steneck says, the projected increases in carbon dioxide buildup and temperature will overwhelm that ability in the decades to come.

Steneck, who does field work in Central America and Mexico, is part of an international science program called “Coral Reef Targeted Research.” Funded by the Global Environmental Facility and the World Bank, the partnership of 40 research institutes seeks to reduce global poverty in developing countries that depend on coral reefs for fishing, tourism and coastal protection.

“We do have a global atmospheric crisis and we have to work on a global level to change it,” Steneck says. “The point is not to be alarmist, but rather to say that we have to redouble our efforts to curb emissions. We need to generate more political will to do it.”

Because eliminating emissions won’t happen overnight, however, Steneck urges the fishing industries in Maine and elsewhere to manage themselves with greater sensitivity to the health of the ecosystems that sustain them.

“The trajectory of a planet that is getting rapidly warmer and more acidic will likely affect organisms globally,” he cautions. “The problem is in our backyard.”

The University of Maine, 14 December 2007 – . Press release.

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