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The enlightening sea

Scientists say shellfish supplies at risk from ocean acidification

By James Wright
September 01, 2009

Evidence of environmental degradation due to climate change is both stark and subtle. While the contraction of polar ice caps in recent decades can be measured in miles, other oceanic shifts over time are trickier to detect or to pin on human intervention. The latest science suggests that changes to the oceans of even the smallest magnitude can impact all marine life, from tiny krill to killer whales. Like many of the gigantic challenges the oceans face, the impact of acidification is best viewed through a microscope.

What some marine biologists and oceanographers are seeing through their magnifying lenses is worth paying attention to. In June, the Woods Hole Oceanographic Institute (WHOI) of Woods Hole, Mass., released a study that said potentially irreversible changes in ocean chemistry - the result of carbon dioxide (CO 2 ) emissions from industrial activity - could cause U.S. wholesale shellfish revenues to drop by 25 percent in the next 50 years, a loss of up to $187 million annually. If shellfish harvests are to decline by 10 to 25 percent, job losses will mount and, more importantly, marine ecosystems will change profoundly. But not everyone associated with the seafood industry is convinced the end is nigh.

According to the report's co-author Scott Doney, senior scientist of marine chemistry and geochemistry at WHOI, the total CO 2 emissions of the past 150 years of human activity are roughly equivalent to emissions of the previous 10,000 years; CO 2 levels in the oceans are at their highest in at least 1 million years. Emissions from burning fossil fuels and deforestation are the root causes of ocean acidification and overall climate change, say scientists.

Rising CO 2 levels cause seawater to become more acidic, endangering shell-forming plants and animals, Doney explained at a June seminar in Portland, Maine, organized by the nonprofit SeaWeb. Mollusks like sea snails, mussels, clams and oysters form their own shells, which are made of calcium carbonite. But increasing CO 2 absorption reduces the amount of calcium carbonate particles that are in the ocean for shell-forming creatures to capture and put to use.

This process, known as ocean acidification, creates a corrosive environment for not only commercially important bivalves and the species that feed on them, but also petite pteropods (a dietary staple of wild salmon) and plankton - the foundation of the entire marine food web. Acidification can also break down already-formed shells, causing pits in the shell surface, exposing the inner layers or dissolving the shells altogether.

Despite Doney's intricate calculations, he remains unsure if the course can be reversed.

"Future uncertainty is based on what humans will do," says Doney. "There is no plausible way to control CO 2 emissions for at least the next 50 years."

 

Scary signals

The threat ocean acidification poses to shellfish isn't breaking news to those who grow them, as their breeding grounds are like massive laboratories. Peter Becker, owner of Little Skookum Shellfish Growers in Shelton, Wash., has a background as an oceanographer and four decades of experience farming clams and oysters. He says Washington's most fertile shellfish grounds, Willapa Bay on the Pacific coast, is sheltered by a breakwater and is not as keenly influenced by open-ocean conditions, the focus of most acidification research.

Becker questions theories 
linking a shortage of oyster seed from the West Coast's major hatcheries - a perplexing phenomenon that began in 2005 - to a declining ocean pH level (see graphic, p. 20). He adds that the "signals" scientists are reporting on get lost in the "general chaos" of coastal ocean chemistry and are not yet fully understood.

"Imagination, popular press reporting by scientists who talk to reporters before they publish in journals and coincidence is not enough to prove causality," says Becker.

Others in the shellfish industry are skeptical of the WHOI study, based on their own theory-dissecting experience in academia.

"No one should take this lightly, but I believe the hypothesis needs much more focus and actual ecosystem observations," says Matt DiMatteo, an executive with American Mussel Harvesters in North Kingstown, R.I. DiMatteo also has a background in marine science. "Obviously, shellfish throughout their entire life cycle are hugely important in the ocean's food chain. If these assumptions prove to be true, the lost revenue is the least to worry about."

Bob Rheault, Ph.D., the president of the East Coast Shellfish Growers Association, says the effects of global warming and rising sea levels seemed so far in the future - and so gradual - that mankind could adapt.

"In contrast, ocean acidification really scares me, because the effects could hit us in our lifetime and the potential disruption to the marine food chain would be catastrophic," says Rheault, president of Moonstone Oysters in Wakefield, R.I.

"Because of the time scale of the chemistry - even if we stop producing CO 2 today - the pH will continue to drop for several hundred years," he adds.

A study published in the May issue of the Proceedings of the National Academy of Sciences cast some doubt about the scope of ocean acidification's destruction. Author Rebecca Gooding, a University of British Columbia researcher, wrote that increased CO 2 emissions will not have direct negative effects on all marine invertebrates and that changing climatic variables should be considered in how various types of organisms will react.

The prevailing opinion from the industry is "show me the proof," but if the oceans' prognosis is as bad as feared, the concerns will be far greater than business. Rowan Jacobsen, author of shellfish-intensive books "A Geography of Oysters" and the upcoming "The Living Shore," offers a sardonic perspective on the WHOI findings.

"It's definitely a big concern, but to me it's a bit like calculating the reduction in oyster bar receipts should a large asteroid hit the Earth," says Jacobsen. "My understanding is that acidification threatens to take out the entire marine food web, in which case it's game over."

 

An inconceivable truth

As far as cataclysmic natural disasters go, the deliberate pace of destruction from ocean 
acidification doesn't quite provide Hollywood drama. The subject first garnered the public's attention when the article "The Darkening Sea" by author Elizabeth Kolbert was published in The New Yorker in November 2006.

"Were the oceans not providing a vast carbon sink," wrote Kolbert, "almost all of the CO 2 that humans have emitted would still be in the air. Atmospheric concentrations would now be nearing 500 parts per million, and the disasters predicted for the end of the century would already be upon us."

Kolbert interviewed Ken 
Caldeira of the Carnegie Institution for Science, who in 2007 wrote, "The effects of increasing atmospheric CO 2 concentrations on the carbonate system in seawater are not reversible on human time scales, and thousands of years will be required before the system can 'recover' to pre-industrial conditions."

Despite such dire diagnoses, ocean acidification is still not a household term - even Al Gore's Academy-Award-winning 2006 documentary "An Inconvenient Truth" didn't delve deeply into the oceans' changing pH as a result of global warming.

However, the subject will soon have its 15 minutes of fame, although the producers of the new film "A Sea Change" are hoping the oceans' plight remains in the public consciousness for much longer. According to husband-and-wife filmmakers Barbara Ettinger and Sven Huseby of Niijii Films, ocean acidification threatens more than 1 million species and is potentially more harmful than any damage that fishermen could cause.

"It is global and it is a 
consequence of what I call the 
unconscious decision to use fossil fuels to provide the energy for modern life," says Huseby, whose family moved when he was a young child from Norway to Alaska's Kenai Peninsula to work in a salmon cannery. He fondly refers to commercial fishermen as "my people."

The film, which had screenings on three continents on the inaugural World Oceans Day on June 8, details co-producer Huseby's personal journey to better understand ocean acidification and its full consequences. (The movie's national TV debut is on Sept. 26 at 8 p.m. on the Planet Green Network.)

Huseby's hope is that his precocious 5-year-old grandson Elias, who appears throughout the film, inherits a world with healthy oceans.

"Only known and observed for the last decade, [ocean acidification] is one of the great externalities of our modern lifestyle," Huseby says. "Over the last two centuries we have been building up this CO 2 debt. Now is the time when this issue needs to be addressed. It will be too late if it is left to future generations."

Ocean acidification has already made its way onto the small screen. In mid-August, Planet Green aired "Acid Test: The Global Challenge of Ocean Acidification" during the network's Blue August promotion, a month-long series of online and on-air programming dedicated to the wonders and mysteries of the world's oceans.

Narrated by actress Sigourney Weaver, the National Resources Defense Council-produced documentary looks at how industrial activity harms the environment.

"The oceans' power to create life is rivaled only by our power to destroy it," reads the film's promotional tagline.

Only for five years have scientists understood that CO 2 emissions can harm the oceans, according to Lisa Suatoni, Ph.D., a 
senior scientist with the NRDC's ocean program.

Emissions science, which "A Sea Change" also explores, is indeed relatively young: As recently as the 1980s, it was widely assumed that carbon emissions couldn't change the pH of the oceans. But the oceanic effects of CO 2 emissions are actually quite easy to understand, says Huseby.

"This is junior high school chemistry," he says. "CO 2 in the atmosphere is absorbed by the oceans, it turns to carbonic acid and eats away at calcium carbonate, which is the building block for all shell-forming organisms. Put some chalk in a glass of vinegar and you'll see, in the extreme, what happens: weaker shells, thinner shells so weak they cannot grow."

 

Copenhagen or bust

Any concerns about oyster, mussel and clam supplies would be extremely premature, but the seafood industry is adopting long-term environmental views as research accumulates. In the sustainable seafood movement, for instance, the market sets the rules: If the harvest or production of any one species is considered unsustainable or harmful to the environment, a powerful company like Wal-Mart or Darden Restaurants could stop purchasing it, and the ensuing publicity could set off a chain reaction of similar responses among seafood buyers.

But Brad Warren, fisheries advisor for Seattle-based Sustainable Fisheries Partnership and former editor of Pacific Fishing , says ocean acidification poses a different challenge, one that the seafood industry cannot change by simply altering its practices as it has to address sustainability.

"You could eliminate all the CO 2 emissions from the fishing industry and not make a bit of difference in the oceans," says Warren. Fishing vessels represent only 0.2 to 0.6 percent of all carbon emissions, he adds.

"From a buyer's point of view, their first impulse is to figure out whether they should stop buying this or that. 'Is it something we did? Do we need to change our ways?' That approach is not applicable here," says Warren. "Buyers want sources that are morally perfect."

The drivers of the type of change that Warren and others say is needed are not big-box supermarkets and nationwide restaurant chains. Climate change and its potential devastation may ultimately persuade governments around the globe to adopt tougher policies for reducing greenhouse gas emissions. Hopes of a legislative paradigm shift are high for this December's United Nations Climate Change Conference (COP15) in Copenhagen, Denmark, as the Kyoto Protocol of 1997 is widely considered to be deficient.

"From the start the Kyoto treaty was so weak to be worthless," says Warren. "[Copenhagen] will be a much more ambitious emissions-reduction bill."

Will ocean acidification be on the agenda when global leaders convene later this year? It should be, Warren explains, and the seafood industry can contribute meaningfully to a carbon-emissions solution.

"The mechanism is a cap-and-trade system. Who's done that? We have," says Warren.

An emissions-trading approach could theoretically borrow a page from the fisheries-management handbook by setting hard limits on emissions and allowing credits - or emissions leftovers - to be bought and sold depending on need. Emissions caps, however, lack global support: Secretary of State Hillary Clinton in July failed to persuade India to accept specific targets for emissions reduction and many other developing countries are reluctant to abide strict limits.

Huseby poses and then answers the question: What can fishermen, and the greater seafood community, do?

"First and foremost they can learn what ocean acidification is - and is not. Second, they can spread the word. Third, they can use their political power to raise the demand for finding new ways to provide energy for modern life. They can join the call for legislation that supports wind, solar and tidal energy," says Huseby. "We have to realize together that there is urgency in this call for change. They are well positioned to be part of the solution."

 

Assistant Editor James Wright can be 
e-mailed at jwright@divcom.com

 

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