Taking fears of acid oceans with a grain of salt

Coral reefs around the world are suffering badly from overfishing and various forms of pollution. Yet many experts argue that the greatest threat to them is the acidification of the oceans from the dissolving of man-made carbon dioxide emissions.

The effect of acidification, according to J.E.N. Veron, an Australian coral scientist, will be “nothing less than catastrophic…. What were once thriving coral gardens that supported the greatest biodiversity of the marine realm will become red-black bacterial slime, and they will stay that way.”

This is a common view. The Natural Resources Defense Council has called ocean acidification “the scariest environmental problem you’ve never heard of.” Sigourney Weaver, who narrated a film about the issue, said that “the scientists are freaked out.” The head of the National Oceanic and Atmospheric Administration calls it global warming’s “equally evil twin.”

But do the scientific data support such alarm? Last month scientists at San Diego’s Scripps Institution of Oceanography and other authors published a study showing how much the pH level (measuring alkalinity versus acidity) varies naturally between parts of the ocean and at different times of the day, month and year.


Matt Ridley, The Wall Street Journal, 7 January 2012. Full article.

1 Response to “Taking fears of acid oceans with a grain of salt”

  1. 1 Jean-Pierre Gattuso 9 January 2012 at 10:31

    Please find below the copy of a comment posted on the Wall Street Journal web site.

    Jean-Pierre Gattuso

    Matt Ridley does not provide an accurate account of ocean acidification science.

    I agree with him that some media have used catchy but inaccurate headlines and I often post comments on the ocean acidification blog (http://oceanacidification.wordpress.com/) to explain that the definition of “acidic” in the Oxford English dictionary is “having the properties of an acid; having a pH of less than 7?. Despite the process of ocean acidification (the acidity of seawater has increased about 30% since preindustrial time), the oceans are alkaline (pH higher than 7) and will not become acidic in the foreseeable future. Hence, the “acid” or “acidic” should not be used when referring to seawater. Note that there are few exceptions, seawater can be acidic in the immediate vicinity of CO2 vents or in purposeful perturbation experiments.

    That being said, and in contrast to Matt Ridley’s statements, ocean acidification does impact marine organisms and ecosystems. Some seem to benefit from it (certain, but not all, plants), others are negatively impacted. The papers alluded to in his article precisely show that biodiversity is considerably less in the CO2 vent sites of Ischia (Italy) and Papua New Guinea. At the pH level expected at the end of this century, 30% of the species are eliminated in Ischia (Hall-Spencer et al., 2008). Likewise, in Papua New Guinea, the considerable diversity of Indo-Pacific corals takes a hit at the acidity level projected in 2100, with a taxonomic richness of hard corals down by 39% (Fabricius et al., 2011).

    Matt Ridley claims that “Laboratory experiments find that more marine creatures thrive than suffer when carbon dioxide lowers the pH level to 7.8”. This is also incorrect. Five experts in the field have recently concluded that there is a high level of confidence that “Ocean acidification will adversely affect calcification” (Gattuso et al., 2011).

    Informing its readership by providing accurate accounts should be a aim of the press. The best way to achieve that goal for the Wall Street Journal and the journalists who contribute to it is to seek the input of the scientific community.

    Jean-Pierre Gattuso
    Scientific Coordinator, European Project on Ocean Acidification

    References cited:

    Fabricius K. E., Langdon C., Uthicke S., Humphrey C., Noonan S., De’ath G., Okazaki R., Muehllehner N., Glas M. S. & Lough J. M., 2011. Losers and winners in coral reefs acclimatized to elevated carbon dioxide concentrations. Nature Climate change 1:165-169.

    Gattuso J.-P., Bijma J., Gehlen M., Riebesell U. & Turley C., 2011. Ocean acidification: knowns, unknowns and perspectives. In: Gattuso J.-P. & Hansson L. (Eds.), Ocean acidification, pp. 291-311. Oxford: Oxford University Press.

    Hall-Spencer J. M., Rodolfo-Metalpa R., Martin S., Ransome E., Fine M., Turner S. M., Rowley S. J., Tedesco D. & Buia M.-C., 2008. Volcanic carbon dioxide vents show ecosystem effects of ocean acidification. Nature 454:96-99.

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