Ocean Acidification: Worse Than the Big Problem We Thought It Was

By Nina Bai | November 25, 2008 12:41 pm

musselsOcean acidification is happening at 10 to 20 times the rate predicted by existing climate models, according to an eight-year study. The rapid acidification of the oceans is linked to global warming and may be a sign that the oceans, the largest absorber of atmospheric carbon dioxide, may not be as hardy as presumed. The changes threaten disaster for marine life with shells that are easily corroded by acid. Marine biologist Nancy Knowlton said, “This is typical of so many climate studies—almost without exception things are turning out to be worse than we originally thought.” [National Geographic News].

The study was done around Takoosh Island off the coast of Washington state and represents the first detailed dataset on variations of coastal pH at a temperate latitude, where the world’s most productive fisheries are found [Times of India]. The researchers took over 24,000 measurements of ocean pH over an 8-year period. During that time, the pH of the seawater was predicted to decrease by only 0.015 points. Instead, the data showed that seawater pH dropped by 0.36 to about 8.1. “The increase in acidity we saw during our study was about the same magnitude as we expect over the course of the next century,” said study co-author Timothy Wootton [National Geographic News].

The researchers found that atmospheric carbon dioxide exhibited a corresponding steady change, with current levels as high as they’ve ever been in the last 650,000 years. About one-third of man-made carbon dioxide is dissolved into the oceans and removed from the atmosphere. But once in seawater, carbon dioxide forms carbonic acid, lowering seawater pH. “Declines in seawater pH were expected to happen very slowly, so we’ve been lax in dealing with the problem, but our study shows ocean acidification may be happening much quicker,” said Wootton [The Guardian].

The study noted a significant decline in large mussels, which normally dominate their niches but have calcium carbonate shells that are weakened or corroded by acid. According to computer models of the local marine life, the rise in acidity is likely to cause substantial falls in the numbers of mussels and large goose barnacles, while algae and populations of smaller barnacles may increase [The Guardian]. The changing balance in the ecosystem may be felt throughout the food chain and may speed up as it goes along, as large populations of certain species begin to die off.

Last year, the Intergovernmental Panel on Climate Change predicted that rising ocean temperatures and acidification would cause the extinction of many coral species by the end of the century. The new study, published in the Proceedings of the National Academy of Sciences [subscription required], paints an even grimmer picture. The researchers would like to collect more data to determine if the situation around Takoosh Island is representative of a global pattern. “It’s been thought pH in the open oceans is well buffered, so it’s surprising to see these fluctuations,” [Wootton] said [BBC News].

Related Content:
80beat: In a More Acidic Ocean, Coral Reef “Skeletons” May Crumble
80beats: A Glimpse into a Future with More Acidic Oceans
DISCOVER: Ocean Acidification: A Global Case of Osteoporosis

Image: flickr / Shayan (USA)

CATEGORIZED UNDER: Environment, Living World
  • Ken Brown

    The plight of the antarctic remains the canary of the seas rapidly changing to become another source putting carbon in to the atmosphere as the Antarctic Ocean which holds a tenth of a percent (0.1%) of the worlds protein as phytoplankton, krill, etc. Yet little has been published on the change in its temperature increase driving that change.

  • Greg

    This is very disturbing, however I am hoping it is merely a localized phenomenon and not representitive of an unexpectedly accelerating global acidification problem. If it is a global problem then mass extinctions of marine life are just around the corner. The reverberating effects up and down the ecosystem will very likely be ones we will not like. Perhaps then impending economic devastation may propel governments to take more action, or perhaps not. It conceivable that if this CO2 emission problem is not tackled effectively in the next 50 years or sooner that it could set into motion a spiral of events to such chaos (I.e. World hunger and world wars over diminishing food resources) that we may come to face the possibility of our own extinction.

  • doug l

    So…if you believe adding CO2 will warm the ocean, then we have no problem since the oceans will release even more CO2…it can only hold what it can hold and the warmer it is, especially at the surface the less it can hold, contrary to what some might think. If you think that CO2 doesn’t warm the environment, then the amount of CO2 in the surface water could turn it acidic but really, the amount in the atmosphere is minor compared to what the oceans will hold, and indeed already do as the planets greatest CO2 source. Either way, it looks like somebody is pining their research on the “what if something terrible happens” despite the manifestly robust and resilient state of our planet’s climate.

  • http://yahoo frank russell

    to:doug says,
    i’m 66 -spent 33 of those years(approx) in california,
    surfing,ocean fishing,etc
    another 33 years in chicago,il
    i can assure you something “BIG” is definitely
    happening to our climate.
    i do not pretend to know what it is-(global warming)(CO2)
    who really knows?
    i kind of think its all of us contributing to global warming,
    but-also i know from literature that we are years overdue for
    another “mini” ice age.its possible we might be accidentally-
    actually saving our atmosphere.
    but also afraid we are too early on pollution to save it.
    beleive me :you do not want to experience the consequences,
    that will come (some already have).

    sincerely

  • http://yahoo frank russell

    see yah !

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