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Acid oceans: the 'evil twin' of climate change

MONTEREY BAY NATIONAL MARINE SANCTUARY, Calif. — Far from Copenhagen's turbulent climate talks, the sea lions, harbor seals and sea otters reposing along the shoreline and kelp forests of this protected marine area stand to gain from any global deal to cut greenhouse gases.

These foragers of the sanctuary's frigid waters, flipping in and out of sight of California's coastal kayakers, may not seem like obvious beneficiaries of a climate treaty crafted in the Danish capital. But reducing carbon emissions worldwide also would help mend a lesser-known environmental problem: ocean acidification.

"We're having a change in water chemistry, so 20 years from now the system we're looking at could be affected dramatically but we're not really sure how. So we see a train wreck coming," said Andrew DeVogelaere, the sanctuary's research director, while out kayaking this fall with a reporter in the cold waters.

Nothing in the treaty negotiations specifically addresses the effects of carbon absorption in the oceans on marine life, which studies show is damaging key creatures' hard shells or skeletons.

Oceans absorb about 25 percent of the world's greenhouse gases pumped into the atmosphere from human activities each year, says a new U.N. report released at the Copenhagen talks this week. That helps slow global warming in the atmosphere, the focus of the Copenhagen talks.

But carbon dissolving in oceans also forms carbonic acid, raising waters' acidity that damages all manner of hard-shelled creatures, and setting off a chain reaction that threatens the food chain supporting marine life, including the lumbering sea mammals along the 276-mile coast of the California sanctuary and the rest of the U.S. West Coast.

By 2100, the report said, some 70 percent of cold water corals — a key refuge and feeding ground for commercially popular fish that also are food for the seals and otters — will be exposed to the harmful effects.

Ocean acidity could increase 150 percent just by mid-century, according to the report by the Secretariat of the U.N. Convention on Biological Diversity.

"This dramatic increase is 100 times faster than any change in acidity experienced in the marine environment over the last 20 million years, giving little time for evolutionary adaptation within biological systems," it said.

The average acidity of oceans' surface water is estimated to increase measurably by the end of the century and will affect marine life, according to Peter Brewer, a senior scientist at the Monterey Bay Aquarium Research Institute.

"The total quantity of carbon dioxide that we've put into the oceans today is around 530 billion tons," Brewer told journalists on a fall fellowship program with the Honolulu-based East-West Center. "Now, it's going up at about 1 million tons an hour. You can't keep doing that without it having some impact."

And Brewer, a member of the Nobel Peace Prize-winning U.N. scientific panel on climate change, said that's only part of the story.

"The trouble is, there's more than one thing going on," he said, citing other effects of climate change that bring, for example, "milder winters, so the deep ocean is getting less oxygen down there."

Given the importance of marine life — some 1 billion people depend on fish as their primary source of protein — climate experts and researchers at the treaty talks have sought to draw more attention to the problem. They call it a particularly important — but largely overlooked — reason for nations to agree on a new climate accord.

In Copenhagen, Jane Lubchenco, head of the National Oceanic and Atmospheric Administration, which manages the sanctuary, said global cuts in greenhouse gases are needed to limit the "blue" carbon absorbed by oceans.

She said the Copenhagen talks have focused on other types of carbon — the "brown" variety from industrial warming gases released by fossil fuel burning, the "green" carbon from burning and chopping down tropical rainforests — but there has been little focus on helping the oceans.

"It's important to recognize that carbon dioxide in the atmosphere is also being absorbed by oceans, and that makes oceans more acidic," Lubchenco told AP.

"I call this ocean acidification climate change's equally evil twin, if you will," she said. "And part of the need to reduce carbon emissions is to both slow down the rate of climate change but also to start repairing the damage that is being done to oceans."

Lubchenco pointed to the harmful effects of carbon absorption in the oceans as decreasing the amount of calcium carbonate that can be used by marine creatures to construct shells or skeletons.

"As the oceans become more acidic, it's harder for corals, oysters, clams, crabs, mussels, lobsters to make their shells or their hard parts, and they dissolve faster," she said.

"So ocean acidification, which is a relatively unappreciated problem, is as important as climate change. It's one that most people haven't heard of. Another way to think of ocean acidification is as osteoporosis of the seas."

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Acidified ocean water rising up nearly 100 years earlier than scientists predicted

Seattle researchers have discovered that vast swaths of acidified sea water are showing up along the Pacific Coast as carbon dioxide from power plants, cars and factories mixes into the ocean. Climate models had predicted that this kind of acidification along the continental shelf where most marine creatures live wouldn't happen until the end of the century.

By Sandi Doughton

Seattle Times science reporter

Climate models predicted it wouldn't happen until the end of the century.

So Seattle researchers were stunned to discover that vast swaths of acidified sea water are already showing up along the Pacific Coast as carbon dioxide from power plants, cars and factories mixes into the ocean.

In surveys from Vancouver Island to the tip of Baja California, the scientists found the first evidence that large amounts of corrosive water are reaching the continental shelf — the shallow sea margin where most marine creatures live. In some places, including Northern California, the acidified water was as little as four miles from shore.

"What we found ... was truly astonishing," said oceanographer Richard Feely, of the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle. "This means ocean acidification may be seriously impacting marine life on the continental shelf right now."

The phenomenon is an aspect of global warming scientists are just beginning to understand.

Acidified ocean water can be fatal to some fish eggs and larvae. It also interferes with the formation of shells and skeletons, harming corals, clams, oysters, mussels and the tiny plankton that are the basis of the marine food web.

"Their shells dissolve faster than they are able to rebuild them," said Debby Ianson, an oceanographer at Fisheries and Oceans Canada and a co-author of the study published today in the online journal Science Express.

The acidified water does not pose a direct threat to people, said co-author Burke Hales, an oceanographer at Oregon State University. "We're not talking battery acid here."

Normally, sea water is slightly alkaline. When carbon dioxide dissolves into the water, it forms carbonic acid — the weak acid that helps give soda pop its tang. That lowers the water's pH, or makes it slightly more acidic. The process also robs the water of carbonate, a key ingredient in the formation of calcium-carbonate shells.

Since the Industrial Revolution, when humans began pumping massive amounts of carbon dioxide into the atmosphere, the oceans have absorbed 525 billion tons of the greenhouse gas, Feely estimates. That's about a third of the man-made emissions during that time.

By reducing the amount of carbon dioxide in the atmosphere, the oceans have blunted the temperature rise due to global warming. But they've suffered for that service, with a more than 30 percent increase in acidity.

Until now, researchers believed most of the acidified water was confined to the deep oceans.

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But during ship-based surveys last year, Feely and his colleagues found the natural upwelling that occurs along the West Coast each spring was pulling the acidified water up onto the continental shelf.

"This is another example where what's happening in the natural world seems to be happening much faster than what our climate models predict," said Carnegie Institution climate scientist Ken Caldeira, whose work suggested it would be nearly 100 years before acidified water was common along the West Coast.

And there's worse to come, the scientists warn.

The acidified water upwelling along the coast today was last exposed to the atmosphere about 50 years ago, when carbon-dioxide levels were much lower than they are now. That means the water that will rise from the depths over the coming decades will have absorbed more carbon dioxide, and will be even more acidic.

"We've got 50 years' worth of water that's already left the station and is on our way to us," study co-author Hales said. "Each one of those years is going to be a little bit more corrosive."

Some creatures, like jellyfish, actually thrive in more acid waters. Adult mussels have a protective coating that may protect their shells.

But many other species are likely to suffer, including commercially important fish like pollock and salmon, which could see their food supply diminish.

"I think this is a red flag for us, because it's right at our doorstep on the West Coast," said Victoria Fabry, a biological oceanographer at California State University San Marcos who was not involved with the study. "It's telling us that we really need more monitoring to figure out what's going on."

Sandi Doughton: 206-464-2491 or sdoughton@seattletimes.com

Copyright © 2008 The Seattle Times Company

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