Ocean Blues Print
Written by Sandra Hines   
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Elkhorn coral. Photo by Jeff Anderson, courtesy of Florida Keys National Marine Sactuary.
While some scientists realized in the 1970s that excess carbon dioxide gas could change ocean chemistry, the phrase “ocean acidification” was only coined in 2003. It wasn’t until 2004 that two definitive papers on the subject appeared in Science and 2006 that a blue-ribbon panel of scientists compiled the most complete report on the subject.

The oceanographic community has been building the evidence about the change for decades, and UW faculty, affiliate faculty and students have played key roles. Just last year the UW’s 276-foot research vessel, the Thomas G. Thompson, carried scientists from Tahiti to Alaska so they could duplicate an ocean chemistry survey in the Pacific done 15 years before, yielding more evidence of the changes under way.

And it may be that the UW’s Friday Harbor Laboratories is a prime place to start nailing down what we don’t know, such as how ocean acidification might affect marine communities and ecosystems as a whole.

We’re not going to kill everything in the oceans, scientists are quick to say. The oceans will adapt. Different species will take the place of any that are displaced or disappear. But are we really ready to accept the changes that might occur? No coral reefs? No Pacific Northwest salmon because they’ve been forced to take up residence someplace else?  

Feely recalls the first time he saw the potential effects of ocean acidification on ocean life. In the mid-’80s, he was leading expeditions in the North Pacific making surveys of ocean chemistry. On the recommendation of a colleague, he invited biology graduate student Victoria Fabry, now a faculty member at California State University at San Marcos, to join the expedition.

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Cavolinia tridentata, Photo by Victoria Fabry.
In the lab on that cruise, Fabry subjected tiny snails called pteropods to water with high amounts of dissolved carbon dioxide. Pteropods have crystal clear, jewel-like shells in various shapes and often are the escargot of choice for juvenile salmon and other fish. The scientists watched with surprise as the shells of living animals turned opaque and then began to dissolve.
 
With ocean acidification it’s not as if everything is starting to swim around in acidic lemon juice, like a cod fillet on a dinner plate. Rather, excess carbon dioxide has changed the balance and proportions of the chemical soup naturally found in the oceans.

As carbon dioxide dissolves into seawater it produces carbonic acid. This acid on its own doesn’t attack the shells and skeletons of sea life. Rather, the carbonic acid begins splitting apart and recombining with other atoms and molecules in seawater. The process uses up some of the essential building blocks of sea life. There is less available for organisms that require carbonate and calcium to build their armor and skeletons. And once built, there has to be enough carbonate and calcium in the water to maintain the protective coverings and skeletons—or else they begin to dissolve.

Feely started publishing his findings in the 1980s, but just as some dismissed early reports of global warming, his theory proved contentious. Some scientists said it was just a North Pacific problem. Others said it would be difficult to determine how much human-made carbon dioxide was actually ending up in the oceans.

It took almost two decades for Feely and colleagues to answer. In his office at the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory—Feely is a NOAA oceanographer as well as a UW faculty member—he pulls out a copy of a 2004 Science magazine article, of which he was lead author.

“These are some of the most important plots of my career,” he says.

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Spiral gilled tube worms. Photo by Paige Gill, courtesy of Florida Keys National Marine Sanctuary.
The three figures show the changes in the carbon chemistry of the Atlantic, Indian and Pacific oceans since the beginning of the Industrial Revolution. It took years, but after a number of worldwide survey programs were completed, Feely and his team used the resulting data to develop the plots that clearly showed this was a global problem.

What’s worse, the effect is not distributed evenly from the top to the bottom of the oceans. A good half of human-made carbon dioxide is in just the upper 10 percent of ocean waters because the oceans turn over very slowly.

“What we showed here,” he says, pointing to the plots, “is that this human-caused carbon dioxide was affecting where calcium carbonate was beginning to dissolve, where the shells would begin to dissolve. As more of that carbon dioxide is absorbed, this transition zone has moved closer and closer to the surface.”

Plants must be in the upper waters in order to get the sunlight they need, and many animals go there to feed. The well-known coral reefs in the tropics are all in shallow water. Some of the organisms, such as the corals, are fixed to hard surfaces and can’t simply move away from the carbon dioxide-enriched waters.