The Azimuth Project
Ocean acidification (Rev #3)


As the concentration of carbon dioxide in the atmosphere increases, it is making the oceans more acidic, in a phenomenon known as ocean acidification. This in turn can hurt calcareous organisms such as shellfish and coral reefs. For more, see:

We need to transfer general information about ocean acidification from Coral reef to this page, leaving information about its effects on reefs over there. We also need to add information about the chemical mechanism of ocean acidification, which we worked out on the Azimuth blog entry Dying coral reefs. The chemistry is surprisingly subtle and poorly understood!

According to the Wikipedia entry on ocean acidification, the basic numbers are as follows:

Between 1751 and 1994 surface ocean pH is estimated to have decreased from approximately 8.179 to 8.104, a change of −0.075 on the logarithmic pH scale which corresponds to an increase of 18.9% in H+ (acid) concentration. By the first decade of the 21st century however, the net change in ocean pH levels relative pre-industrial level was about -0.11, representing an increase of some 30% in “acidity” (ion concentration) in the world’s oceans.

Here is a plot showing the acidification of the oceans:


  • Ocean acidification, Wikipedia.

  • AUTHOR???, Climate sensitivity to the carbon cycle modulated by past and future changes in ocean chemistry, Nature Geoscience 2 (2009), 145–150. doi:10.1038/ngeo416

  • AUTHOR???, Past constraints on the vulnerability of marine calcifiers to massive carbon dioxide release, Nature Geoscience 3 (2010), 196–200. doi:10.1038/ngeo755

category: oceans