Wednesday, July 05, 2006
Michigan's secret tourism promotion plan: Build more coal plants and wipe out ocean resort attractions
Growing Acidity of Oceans May Kill Corals
By Juliet Eilperin
The escalating level of carbon dioxide in the atmosphere is making the world's oceans more acidic, government and independent scientists say. They warn that, by the end of the century, the trend could decimate coral reefs and creatures that underpin the sea's food web.
Although scientists and some politicians have just begun to focus on the question of ocean acidification, they describe it as one of the most pressing environmental threats facing Earth. . . .
For decades, scientists have viewed the oceans' absorption of carbon dioxide as an environmental plus, because it mitigates the effects of global warming. But by taking up one-third of the atmosphere's carbon dioxide -- much of which stems from exhaust from automobiles, power plants and other industrial sources -- oceans are transforming their pH level.
The pH level, measured in "units," is a calculation of the balance of a liquid's acidity and its alkalinity. The lower a liquid's pH number, the higher its acidity; the higher the number, the more alkaline it is. The ph level for the world's oceans was stable between 1000 and 1800, but has dropped one-tenth of a unit since the Industrial Revolution, according to Christopher Langdon, a University of Miami marine biology professor.
Scientists expect ocean pH levels to drop by another 0.3 units by 2100, which could seriously damage marine creatures that need calcium carbonate to build their shells and skeletons. Once absorbed in seawater, carbon dioxide forms carbonic acid and lowers ocean pH, making it harder for corals, plankton and tiny marine snails (called pteropods) to form their body parts. . . .
Some have questioned global-warming predictions based on computer models, but ocean acidification is less controversial because it involves basic chemistry. "You can duplicate this phenomenon by blowing into a straw in a glass of water and changing the water's pH level," Lovejoy said. "It's basically undeniable."
Hugo A. Lo?iciga, a geography professor at the University of California at Santa Barbara, is one of the few academics to question the phenomenon. A groundwater hydrologist, Lo?iciga published a paper in the May edition of the American Geophysical Union's journal that suggested the oceans may not become so acidic, because enough carbonate material will help restore equilibrium to them. . . .
Two dozen scientists have written a response questioning this assumption, since it would take thousands of years for such material to reach the oceans from land.
"The paper by Lo?iciga ignores decades of scholarship, presents inappropriate calculations and draws erroneous conclusions that simply do not apply to real ocean," they wrote. They added that, unless carbon dioxide levels in the atmosphere stabilize soon, the seas will soon exceed the Environmental Protection Agency's recommended acidity limits. . . .
"It's going to be on a global scale and it's also chronic," Langdon said of ocean acidification. "Twenty-four/seven, it's going to be stressing these organisms. . . . These organisms probably don't have the adaptive ability to respond to this new onslaught."
Stanford University marine biologist Robert B. Dunbar has studied the effect of increased carbon dioxide on coral reefs in Israel and Australia's Great Barrier Reef. "What we found in Israel was the community is dissolving," Dunbar said. . . .
Although the fate of plankton and marine snails may not seem as compelling as vibrantly colored coral reefs, they are critical to sustaining marine species such as salmon, redfish, mackerel and baleen whales.
"These are groups everyone depends on, and if their numbers go down there are going to be reverberations throughout the food chain," said John Guinotte, a marine biologist at the Marine Conservation Biology Institute. "When I see marine snails' shells dissolving while they're alive, that's spooky to me."