Scientists worry as oceans grow more acidic

WASHINGTON | Seven hundred miles west of Seattle in the Pacific at Ocean Station Papa, a first-of-its-kind buoy is anchored to monitor a looming environmental catastrophe.

Forget about sea levels rising as glaciers and polar ice melt, and increasing water temperatures affecting global weather patterns. As the oceans absorb more and more carbon dioxide and other greenhouse gases, they are gradually becoming more acidic.

Some scientists fear that the change may be irreversible.


At risk are sea creatures up and down the food chain, from the tiniest phytoplankton and zooplankton to whales, from squid to salmon to crabs, coral, oysters and clams.

The oceans are already 30 percent more acidic than they were at the beginning of the Industrial Revolution, as they absorb 22 tons of carbon dioxide a day. By the end of the century they could be 150 percent more acidic.

“Everything points to dramatic effects,” said Richard Feely, an oceanographer with the National Oceanic and Atmospheric Administration in Seattle. “There are suggestions the entire ecosystem could change over time.”

Originally, scientists thought that the oceans could be one of the solutions to the buildup of greenhouse gases, as they absorb about one-third of the carbon dioxide that is emitted worldwide. But they now know that the fundamental chemistry of the oceans has changed, and the possible effects seem to grow more nightmarish as research accelerates.

“It seems like it is a one-way street, and that is alarming,” said Steven Emerson, a professor of oceanography at the University of Washington. “The pH of the oceans could be lowered permanently.”

Emerson was the lead scientist on the team that built the buoy at Ocean Station Papa, where weather measurements have been taken since the 1940s. The 10-foot-diameter buoy is equipped with sensors that, among other things, measure the amount of carbon dioxide that is being absorbed by the North Pacific and the pH, or acid levels, of the ocean. Anchored in water 5,000 feet deep, the buoy relays its information to onshore scientists by satellite.

The increasing acidity can eat away at the shells of crabs, oysters, clams and nearly microscopic organisms known as krill and pteropods. It also inhibits calcification, the process in which these animals rebuild their shells. Without shells, most of the animals probably would die.

Krill and pteropods are a major food source for juvenile salmon, herring, pollock, cod, mackerel and other fish.

“When you start messing with the lower end of the food chain, it can dramatically affect the higher end of the food chain,” Feely said.

Squid also are sensitive to higher acidity, which affects their blood circulation and respiration. Colonies of coral, including those in tropical waters and those found deep off the Northwest coast, could disappear. Eventually, the acidification will reach into inland waters, affecting oyster beds and clamming areas.

Feely said that 500 million to 1 billion people worldwide depended on fish for survival.

Les Blumenthal, KansasCity.com, 15 December 2007. Article.


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