Oceanography: Sick seas

Oceanography: Sick seas

by Jacqueline Ruttimann

News Feature
Nature 442, 978-980(31 August 2006) | doi:10.1038/442978a; Published online 30 August 2006

The rising level of carbon dioxide in the atmosphere is making the world's oceans more acidic. Jacqueline Ruttimann reports on the potentially catastrophic effect this could have on marine creatures.

It's not hard to imagine a tonne of water: it is a week's worth of not-very-deep baths. Getting to grips with a billion tonnes of water is more of a challenge. That would be a similar bath for every man, woman and child on the planet; a week's worth of flow for the Nile. To really expand your mind, go further still, to a billion billion tonnes - enough water to give every human a day's worth of the Nile instead of a shallow bath. There are dwarf planets that weigh less than a billion billion tonnes. Yet Earth's oceans weigh more.

If it is hard to imagine something so vast, it is perhaps even harder to imagine changing it. But humanity is changing the oceans. From the tropics to the Arctic, the seas are sucking up human-driven emissions of carbon dioxide - about half of the excess belched into the atmosphere over the past two centuries from fossil-fuel burning and cement manufacturing plants1. When carbon dioxide dissolves in water, carbonic acid is produced: as a result the oceans are becoming more acidic. "It's basic chemistry," says Joanie Kleypas, a marine ecologist at the National Center for Atmospheric Research in Boulder, Colorado. "It's hard to say that this is not happening."

Read more at:
http://www.nature.com/nature/journal/v442/n7106/full/442978a.html