The Great Oyster Crash and Why Ocean Acidification Is “A Ticking Time Bomb” for Both Marine Life and Humanity

by Kiley Kroh

Americans consume approximately 700 million farmed oysters per year.  Despite our love for these briny bivalves, shellfish and the coastal communities that depend on them face serious threats.

In a recent piece, Eric Scigliano examines “The Great Oyster Crash” of 2007, in which oyster seed (larvae) off the coast of Oregon and Washington began dying by the millions, seemingly without cause.  After taking aggressive measures to eliminate bacteria in the tanks, and failing to halt their losses, the owners began to suspect the problem was a more fundamental change in the makeup of the oceans.  With the help of local scientists, they found that their losses were directly linked to a far more ominous phenomenon: ocean acidification.

As Scigliano explains, “the oceans are the world’s great carbon sink, holding about 50 times as much of the element as the air.”  As carbon emissions from burning fossil fuels and other industrial processes rise, so too does the level of acidity in the oceans.  Once it reaches a certain threshold, ocean acidification becomes lethal to many species, including clams and oysters, which become unable to build the shells or skeletons they need to survive.

The rise in acidity and subsequent oyster crash took a significant toll on coastal communities – from 2005 to 2009, West Coast production dropped from 93 million pounds to 73 million pounds, representing  $11 million in lost sales. This case is among the earliest examples of ocean acidification imposing a direct effect on the economy. Unfortunately, we can safely say it is far from the last.

By installing new technology to carefully monitor ocean temperatures and chemistry, some west coast hatcheries were able to rebuild, but their bounty might be short-lived.  While temporary mitigation measures have been successful, they are just that – temporary.  Scientists from Mexico, Canada, and the United States found that upwellings of acidic water like those that wiped out the Pacific hatcheries operate on a delay of several decades – the water rising from the deep ocean today holds CO2 absorbed approximately 30 to 50 years ago.  In the last 50 years, the levels of CO2 in the atmosphere have risen 25 percent – a terrifying presage for the health of the world’s oceans. Burke Hales, one of the scientists involved in the research, explains:

“We’ve mailed a package to ourselves … and it’s hard to call off delivery.”

Benoit Eudeline, chief hatchery scientist for Taylor Shellfish Farms, the largest US producer of farmed shellfish, likened the current situation to “sitting on a ticking time bomb.”

The threat of ocean acidification spreads far beyond the oyster industry and carries potentially catastrophic implications for the entire food chain. Basically any fish that might find its way onto your dinner plate relies on krill, plankton, snails or other shelled creatures that stand to be hit earliest and hardest by acidification.  The chart below, for instance, shows that about half the annual catch by value in the U.S. comes from mollusks and crustaceans and another 24 percent are animals that directly feed upon these calcifiers – representing billions of dollars and millions of jobs at stake. (See chart above.)

The damaging effects of ocean acidification will likely be felt even more acutely beyond American shores.  A recent study found that mollusk fisheries will decline most in poor countries that are already struggling with protein deficiencies.  In Madagascar, one of the countries the study predicted would be hit hardest, fishing  provides 7 percent of the GDP and generates nearly half a million jobs – and local officials confirm the effects of both climate change and ocean acidification are already being felt.

Though advancements in science and fisheries management can help provisionally assuage the blow of ocean acidification, ultimately, only significant measures to reduce carbon emissions in the atmosphere will prevent the oceans from becoming more acidic and threatening more species.  The groundbreaking 2005 study on ocean acidification conducted by The Royal Society recommended “a major internationally coordinated effort” to stem the tide of acidification, unequivocally stating, “action needs to be taken now to reduce global emissions of CO2 to the atmosphere to avoid the risk of irreversible damage to the oceans.”  Six years later, we’re still waiting.

— Kiley Kroh is associate director of Ocean Communications at the Center for American Progress

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12 Responses to The Great Oyster Crash and Why Ocean Acidification Is “A Ticking Time Bomb” for Both Marine Life and Humanity

  1. john tucker says:

    Good article – sometimes I feel like ocean acidification has been worse than neglected – its been totally forgotten. It alone is cause enough to make hard and sometimes expensive choices to aggressively reduce carbon emissions.

  2. Douglas says:

    A question I’ve had for a while: Does acidification have any impact on melt rates? I.e. does ice, such as the floating arctic sea ice, melt any faster or slower in more acidic seawater?

  3. Joan Savage says:

    Isn’t there more at stake with acidification than loss of human food, although that is significant?

  4. Greg says:

    Doug: tiny, negligible effects.

    There’s a good tutorial on the basics of ocean acidification at Skeptical Science, called OA Not OK.

    The authors have promised a second series on the effects of ocean acidification. Keep an eye out.

  5. Colorado Bob says:

    Plankton, at some point that crashes.

  6. Joan Savage says:

    Turns out some phytoplankton have calcium carbonate shells that are weakened by acidity.

  7. Kevin says:

    I have two questions:
    If ” the water rising from the deep ocean today holds CO2 absorbed approximately 30 to 50 years ago” and it is causing this much of problem now, then what will the oceans be like in 2030?2050?

    If all emissions were cut to zero today, There would still be an impact on the oceans since there is a delay. How big would the impact be on the oceans?

  8. Paul magnus says:


    This risk is more certain than a ticking time device. The bomb is already going off…

  9. Colorado Bob says:

    By Timothy B. Wheeler, The Baltimore Sun

    8:06 p.m. EDT, September 14, 2011

    The Chesapeake Bay looks like a dirty bathtub, its waters turned brown with mud and awash in pollution and floating debris, including uprooted trees, propane tanks, even a battered dining-room chair.

    Braving boat-damaging hazards, scientists are swarming over the bay to see if the massive stormwater runoff from Tropical Storm Lee last week is going to knock the troubled estuary for another loop, just as it was recovering from an especially rough summer.

    “It just doesn’t look right,” Jamie Strong, a biologist with the Maryland Department of Natural Resources, said of the malted-milk hue of the water as he and state biologist Zofia Noe cruised north from the Bay Bridge on Wednesday to sample water conditions. Along the way, they dodged partially submerged tree trunks — not always successfully — and skirted sprawling mats of grass and trash atop the water.,0,4488674.story

  10. Lewis Cleverdon says:

    The widely reported decline of plankton thus far would be accelerated by rising acidification – if no effective intervention is achieved – and since their minute shells are built from carbon dissolved in the water they inhabit, their accelerating decline translates directly into the decline of the oceanic carbon sink.

    This implies a net rise of annual rates of atmospheric accumulation of our carbon emissions of potentially up to 50%.

    Thus alongside the oceans’ thermal inertia, and the sulphate parasol’s closure, acidified ocean upwellings looks like the third ‘pipeline’ threat nullifying reliance on simply ending our GHG emissions as the means to avoid catastrophic global warming.

    Quite how the US EPA failed for so long to certify anthro-CO2 as an environmental poison, with this outcome entirely predictable for 50 years, seems unexplained.



  11. Lisa Boucher says:

    Excellent article. The linked chart needs to be bigger.

  12. Bruce S says:

    Kevin, The Co2 that upwells on the west coast is carried by intermediate waters which sub ducted off the coast of japan 35-50 years ago. The Co2 is the product of atmospheric Co2 levels when it left the surface plus Co2 released by bacteria when they consume organic matter. If biological production doesn’t change to much we can expect to see pH decrease .3 to .4 by 2100. So you might see 7.4 or even 7.3 upwelled water by 2100.