Southern Ocean close to acid tipping point

Australian researchers have discovered that the tipping point for ocean acidification caused by human-induced CO2 emissions is much closer than first thought.

Scientists from the University of New South Wales (UNSW) and CSIRO looked at seasonal changes in pH and the concentration of an important chemical compound, carbonate, in the Southern Ocean.

The results, published in today’s Proceedings of the National Academy of Science, show that these seasonal changes will actually amplify the effects of human carbon dioxide emissions on ocean acidity, speeding up the process of ocean acidification by 30 years.

Dr Ben McNeil, senior research fellow at the UNSW’s Climate Change Research Centre, says the ocean is an enormous sink for CO2, but unfortunately this comes at a cost.

“The ocean is a fantastic sponge for CO2, but as it dissolves in the ocean it reduces the pH of the ocean, so the ocean becomes more acidic,” says Dr McNeil.

This acidification makes life especially hard for marine creatures such as pteropods – an important type of plankton found in the Southern Ocean – whose shells are made up largely of calcium carbonate.

Bianca Nogrady, ABC Science, 11 November 2008. Article.

1 Response to “Southern Ocean close to acid tipping point”

  1. 1 gattuso 25 November 2008 at 15:38

    The terminology used in this article is not scientifically accurate. The definition of “acidic” in the Oxford English dictionary is “having the properties of an acid; having a pH of less than 7”. This definition does not apply to un-manipulated seawater now nor in the foreseeable future. Hence, the adjective “acidic” should not be used. Note that there are some exceptions, for example in the immediate vicinity of CO2 vents.

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