« September 2009 Table of Contents
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
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."
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
"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,
"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
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
"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
"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
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
Huseby's hope is that his precocious 5-year-old grandson
Elias, who appears throughout the film, inherits a world with
"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
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,
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
"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
"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
Assistant Editor James Wright can be