Australasian Science: Australia's authority on science since 1938

Underwater Acid Lab

By Stephen Luntz

The discovery of carbon dioxide seeps surrounded by coral reefs has given Dr Katharina Fabricius a chance to investigate our oceanic future. The news is not good.

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Ocean acidification is gaining a profile as the second major danger from our fossil fuel addiction. Many marine species depend on seawater that is slightly alkaline, and carbon dioxide makes water acidic. Rising atmospheric carbon dioxide therefore makes the ocean less alkaline.

Researchers worldwide have been trying to predict the damage to coral reefs associated with acidification (AS, May 2008, pp.31–33), typically by setting up large experimental tanks with different CO2 concentrations. However, the studies are hampered by their temporary nature. “In the lab most experiments last just a few weeks,” says Dr Katharina Fabricius of the Australian Institute of Marine Sciences (AIMS). Consequently it is impossible to tell if species will eventually adapt.

Ten years ago Fabricius was exploring coral reefs off Papua New Guinea and discovered three carbon dioxide seeps. “At the time acidification was not on my radar,” says Fabricius. “I was looking at water quality, so I noted them, and when I started to be concerned about acidification remembered and organised the first expedition.”

Carbon dioxide vents exist elsewhere, but come with poisonous heavy metals or hydrogen sulfide, creating a poor model for future global conditions. Fabricius established, however, that the PNG vents were seeping pure carbon dioxide, something unknown in any equivalent location...

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