In a small area of the southern ocean dissolve the shells of marine snails. This is the first evidence that the underwater inhabitants already suffer from man-caused acidification of the seas.

Gerant Tarling from the British Antarctic survey and his colleagues caught a few pteropod in early 2008 and under the electronic microscope saw traces unusual damage the outer layers of their hard shells.

Pteropod mollusk Limacina helicina from the White sea (photo by Alexander Semenov).

Allocated us carbon dioxide will not only warming, but also to changes in the chemistry of the ocean, because it dissolves in water to form carbonic acid. Now pH drops to about 0.1% per century - the highest rate in the last 300 million years. Laboratory experiments showed that will suffer as a result organisms with hard shells (corals, mollusks), because to create bowls they take out of the water, calcium carbonate, and the more carbon dioxide, the more water hydrogen ions. They react with carbonate ions and make them unsuitable to the formation of calcium carbonate.

The most vulnerable are those organisms which, like the pteropod, build a shell made of aragonite, a form of calcium carbonate, is very sensitive to acidification. By 2050 in the ocean will be felt serious shortage of this substance. Now it quite yet, but Mr. Tarling suspected that today can be designated with a deficit of aragonite.

He had been in the area of South Georgia, where the surface are of deep water, nature poor aragonite. The surface layer there is diluted, but not enough to cause problems. At the same time, this place is especially vulnerable to acidification. "Such pockets will become more and more until it encounters", - stressed the expert.

According to him, in this regard, the Arctic will overtake the Antarctic. Depleted aragonite region was observed at the Northern coast of Canada in 2008.

The only way to stop the acidification of the ocean - to reduce emissions of carbon dioxide. It has been suggested that we could add to the ocean several megatons of lime in order to reduce acidity. However, according to experts, it is impractical, because it is too expensive.

The study is published in the journal Nature Geoscience.

Prepared according to NewScientist.