Global Warming Chief Among Threats to Coral Reefs

The report was released by NOAA today at the opening of the 11th International Coral Reef Symposium in Fort Lauderdale where more than 2,500 scientists and government officials are gathered this week to discuss coral reef protection strategies and research priorities to further protection of sensitive coral ecosystems.

The symposium's theme, Reefs for the Future, highlights the importance of the world's coral reefs, as well as the urgent need for accelerated action to protect them.

"The report shows that this is a global issue," said Tim Keeney, deputy assistant secretary of commerce for oceans and atmosphere and co-chair of the U.S. Coral Reef Task Force. "While the report indicates reefs in general are healthier in the Pacific than the Atlantic, even remote reefs are subject to threats stemming from climate change, as well as illegal fishing and marine debris."

U.S. coral reef ecosystems, particularly those near populated areas, continue to face threats from human activities such as coastal development, pollution, fishing, sedimentation and recreational use, finds the report, "The State of Coral Reef Ecosystems of the United States and Pacific Freely Associated States: 2008."

"NOAA's coral program has made some significant progress since it was established 10 years ago, but we need to redouble our efforts to protect this critical resource," said NOAA Administrator Conrad Lautenbacher Jr.

More than 270 scientists and managers working in the Gulf of Mexico, the Caribbean, the Atlantic and and the Pacific authored the 15 chapters of the report - each focused on one jurisdiction. The scientists graded the coral ecosystems on a five tier scale - excellent, good, fair, poor and unknown.

Coral reef off the coast of southeastern Florida (Photo by D. Gillam courtesy NOAA)

The report details coral reef conditions in the U.S. Virgin Islands, Puerto Rico, Navassa Island, southeast Florida, the Florida Keys, Flower Garden Banks, the Main Hawaiian Islands, the Northwestern Hawaiian Islands, American Samoa, the Pacific Remote Islands, the Republic of the Marshall Islands, the Federated States of Micronesia, the Commonwealth of the Northern Mariana Islands, Guam and the Republic of Palau.

The 2008 report is the third in a series tracking the condition of U.S. coral reef ecosystems at local and national scales. The reports show that the condition of U.S. coral reefs has been declining for decades. Since the last status report was released in 2005, two coral species - elkhorn and staghorn corals - have become the first corals ever listed as threatened under the U.S. Endangered Species Act.

"Coral reefs are extraordinary living ecosystems that draw visitors, support our economy and protect our beaches and homes from erosion and storm surge," said Florida Governor Charlie Crist told the conference participants. "Florida will continue to take steps, such as new legislation reducing nutrients and other pollutants in the ocean, that will protect these sensitive ecosystems for residents and visitors for generations to come."

Governor Crist held a bill signing ceremony for Senate Bill 1302, which will eliminate the use of ocean outfalls for wastewater disposal in southeast Florida by 2025.

An extensive, beautiful coral reef ecosystem stretches more than 100 miles along the southeast Florida coast, from Miami-Dade to Martin County. These reefs are part of the third longest reef system in the world and are one of the greatest natural resources in Florida and the United States.

The state of Florida, in partnership with NOAA, also manages the coral reefs in the Florida Keys National Marine Sanctuary.

"Florida is proud to help sponsor this internationally-recognized conference that brings together thousands of representatives from the marine science, resource management, conservation and policy-making communities," said Florida's Environment Secretary Michael Sole. "By collaborating with our partners on the best available current science, as well as future research, we can better protect our coral reef systems, and continue to preserve these vital habitats that provide shelter, food, breeding and nursery areas for a rich and diverse assortment of marine life, including important recreational and commercial fisheries."

The world's oceans are acidifying far more rapidly than scientists expected, with serious implications for the future of corals, reef algae, shellfish and some ocean food chains, according to a keynote paper presented at the symposium by Australian earth scientist Malcolm McCulloch of the ARC Centre of Excellence for Coral Reef Studies and Australian National University.

The paper presents new coral evidence suggesting the oceans may have acidified by almost a third of a unit of pH as a result of human emissions of the greenhouse gas carbon dioxide.

Coral in the waters of Raiatea, the second largest of the islands of French Polynesia (Photo courtesy ARC Centre of Excellence for Coral Reef Studies)

"We've measured an increase of almost 0.3 of a pH unit in acidity in corals, which is much higher than has been detected so far in ocean water itself," Professor McCullough said.

"This suggests either that the corals are somehow amplifying the effect - or else that we may have gravely underestimated the rate at which the burning of fossil fuels is turning the oceans acidic," he said.

Acidic oceans may cause living creatures which depend on an alkaline environment to cease forming their shells and skeletons. This applies to about a third of sea life, said McCullough.

As the oceans become saturated with carbon dioxide, their ability to absorb carbon from the atmosphere is expected to decline, leaving more CO2 in the air to insulate the planet and accelerate the pace at which it warms.

McCullough presented evidence that coralline algae - the "cement" that binds together the fronts of coral reefs against the ocean's power - will be more seriously affected than even the coral itself, causing reefs to crumble away.

How serious the impact of ocean acidification will be on corals themselves is not yet clear, McCullough says. "We are unsure of the explanation for why the corals are showing these high levels of acidification - but we need to find out, and quickly."

The International Coral Reef Symposium convenes every four years, and this year it coincides with the International Year of the Reef, a worldwide campaign to raise awareness about the value and importance of coral reefs and threats to their sustainability.

Copyright Environment News Service (ENS) 2008. All rights reserved.