Ocean Acidification: A Global Case of Osteoporosis

[Zeno Swijtink]

Ocean Acidification: A Global Case of Osteoporosis
Industrial carbon dioxide is turning the oceans acidic, threatening the foundation of sea life.
by Kathleen McAuliffe
published online July 16, 2008

It all seemed so convenient: As our smokestacks and automobile tailpipes spewed ever more carbon dioxide into the air, the oceans absorbed the excess. Like a vast global vacuum cleaner, the world’s seas sucked CO2 right out of the atmosphere, mitigating the dire consequences of global warming and forestalling the melting of glaciers, the submergence of coastlines, and extremes of weather from floods to droughts. So confident were we in the seas’ seemingly limitless capacity to absorb our gaseous waste that, by the turn of the millennium, the United States, Germany, and Japan were actually proposing to compress CO2 from power plants into a gooey liquid and pipe it directly into the abyss.

The first tests of the plan were an eye-opener. When the compressed material was introduced into laboratory tanks, the spines of sea urchins and the shells of mollusks dissolved. Surprised, researchers launched studies to see how marine animals in laboratory tanks and in the wild would fare with CO2 concentrations much lower than those in the original tests. They were stunned. “We found that mere absorption of CO2 from the atmosphere into the ocean was enough to harm marine creatures,” says Ken Caldeira, a chemical oceanographer now at the Carnegie Institution of Washington in Stanford, California.

The problem was that, having swallowed hundreds of billions of tons of greenhouse gases since the start of the Industrial Revolution, the oceans were becoming more acidic. And not just in a few spots. Now the chemistry of the entire ocean was shifting, imperiling coral reefs, marine creatures at the bottom of the food chain, and ultimately the planet’s fisheries.

In 2003 Caldeira reported these findings in the journal Nature, coining the term “ocean acidification.” One might think the news would spread around the world with the speed and force of a tsunami. But scientific discoveries take time to be digested and disseminated. Only recently have the far-flung implications of this development begun to register beyond the rarefied sphere of marine biologists.

“It’s the most profound environmental change I’ve seen in my entire career, and nobody saw it coming,” says Thomas E. Lovejoy, a biologist and president of the H. J. Heinz III Center for Science, Economics and the Environment in Washington, D.C.

Lovejoy is not the only one alarmed by the development. “It’s just been an absolute time bomb that’s gone off both in the scientific community and, ultimately, in our public policymaking,” Rep. Jay Inslee (D-Wash.) told The Washington Post when first briefed on the matter in the spring of 2006. Congress is now scrambling to get up to speed by holding hearings on the issue and discussing federal legislation that could allocate roughly $100 million to study the impact of industrial emissions on marine ecosystems.

Even the fishing industry has been caught off guard. Fisheries are “the ultimate canary in the coal mine of ocean acidification,” says Brad Warren, the former editor and publisher of Pacific Fishing magazine, who recently launched the nonprofit Sustainable Fisheries Partnership to encourage seafood enterprises to confront the problem through policy initiatives.

While the existence of global warming was fiercely debated for decades, ocean acidification has been rapidly accepted by the scientific community as a real and imminent hazard. “It is very complicated to pin the heating of the planet on a single gas, but ocean acidification involves straightforward chemistry,” says Robert B. Dunbar, professor of geological and environmental sciences at Stanford University. Since it is easy to chart the step-by-step progression of the problem, there is widespread consensus that we are marching toward disaster at a pace that is impossible to ignore.

An analysis of CO2 preserved in ice cores shows that for more than 600,000 years the ocean had a pH of approximately 8.2 (pH is the acidity of a solution measured on a 14-point scale, with a pH below 7 being acidic and above 7, basic). But since 1800, the beginning of the Industrial Revolution, the pH of the ocean has dropped by 0.1 unit. That may not sound like much, but pH is a logarithmic scale, so the decline in fact represents a whopping 30 percent increase in acidity. With the oceans now absorbing man-made CO2 at a rate of 22 million tons a day and climbing, the situation is certain to worsen rapidly. More than a dozen projections by the International Panel on Climate Change indicate that ocean pH by the end of the century could drop as low as 7.8, which would correspond to a 150 percent increase in acidity since preindustrial times. “A drop of that magnitude is more than we’ve seen in 20 million years,” says Richard A. Feely, supervisory oceanographer at the National Oceanic and Atmospheric Administration (NOAA) Pacific Marine Environmental Laboratory in Seattle. “That’s going to profoundly change the ecology of the sea as we now know it, in ways that could potentially be devastating.”

Osteoporosis Under the Sea

Most vulnerable to the assault of higher acidity, scientists say, is any creature that makes a calcium carbonate shell. A look at the chemistry of ocean acidification explains why. When CO2 from the atmosphere combines with water, it produces carbonic acid (the ingredient that gives soft drinks their fizz) and decreases carbonate ions, a key building block of marine animals’ shells. As the oceans become more acidic, this material will become increasingly scarce, hindering the ability of shelled organisms to make and maintain their homes. Like human bones whittled by osteoporosis, their exoskeletons will grow thin and brittle or—mirroring what happened to the test animals at CO2 injection sites—dissolve.

cont. at https://discovermagazine.com/2008/ju...f-osteoporosis

[Sylph]

As a diver, I have seen areas of the world where the corals are dead and dying. In the Cook Islands, the locals didn't know exactly why this was happening, but various theories included, global warming, silt run-off and the crown of thorns starfish. Perhaps the explanation is acidification. Scary, scary information.
Apparently, acid water is threatening Northern California ecosystems, too:

https://news.nationalgeographic.com/news/2008/05/080522-acid-oceans.html

At one spot in northern California, waters acidic enough to corrode seashells now rake the shore, researchers point out."The models suggested they wouldn't be corrosive at the surface until sometime during the second half of this century."

https://www.mailtribune.com/apps/pbcs.dll/article?AID=/20080605/LIFE/806050303/-1/OREGONOUTDOORS02


Off Northern California, acidified water was found four miles from shore.
"What we found ... was truly astonishing," said Richard A. Feely, an oceanographer at the NOAA lab. "This means ocean acidification may be seriously impacting marine life on the continental shelf right now."

https://www.climateshifts.org/?p=224
One third of the major reef-building coral species are vulnerable to extinction, and the pace of destruction is increasing so it is conceivable that the "rainforests of the ocean" could be wiped out this century.
Emerging evidence indicates some corals have suffered a 20 per cent reduction in their growth rates, which researchers consider to be due to the rising acidification of sea water making it harder for them to build their chalky skeletons.