Scientific Method / Science & Exploration

Oceans on acid

Never mind global warming. More carbon in the air will almost certainly mean …

Hot on the heels of the AAAS meeting in St. Louis comes the American Geophysical Union's 2006 Ocean Sciences Meeting. In contrast to the broad range of scientists that gathered in St. Louis, this group met a bit closer to the ocean that they study. In Honolulu. Many science-types who are reading this will now undoubtedly be reconsidering their chosen field of study.

Two of the presentations there took me right back to grammar school chemistry, where I was taught that CO2 + H2O could produce H2CO3, commonly known as carbonic acid. This is not a very strong acid, but it can noticeably change the pH of the water, so that water exposed to high concentrations of CO2 will be somewhat acidic. Meanwhile, regardless of whether it's warming the earth or not, there's a lot more CO2 in the atmosphere, making the entire ocean a bit of a high school chemistry project. Current estimates suggest that within 100 years, the pH of the ocean may drop from 8.2 to 7.7. Should that happen, the presentation suggests that it will be as acidic as the time of the great extinctions that wiped out the dinosaurs and lots of oceanic life.

The press alert notes that there is some evidence that at other times, oceanic life has tolerated similar pH levels much better, so there's clearly more at work and details for researchers to study in more detail. If any species is affected by changing pH, though, it's going to be the animals that create shells made of calcium carbonate, which dissolves in acidic conditions. One such animal, and one that's already having trouble coping with rising ocean temperatures, is the coral. Another study presented at the meeting suggests that a doubling of carbon dioxide in the atmosphere would be enough to keep corals from recovering from normal damage caused by life at sea. We're still a long way off from that amount of CO2 in the atmosphere, but it reinforces the idea that corals are worth keeping an eye on as a probable early indication of environmental damage caused by high atmospheric carbon. So, although neither of these studies point to imminent disaster, they do suggest that there may be significant problems that are being overlooked amidst the hue and cry over global warming.

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