Acid in Arctic waters eating away at shellfish

Marine food chain could be threatened

Greenhouse gas emissions from vehicles, power stations and industries far to the south are putting shellfish in the Arctic Ocean at risk, an international team reports in the Nov. 20 edition of the journal Science.

Acidification may put “some species at risk,” the researchers said, saying this could have a major impact on the entire marine food chain.

And acidification is expected to increase as sea ice cover decreases due to global warming, they say.

Ten years of study in the Beaufort Sea showed the seawater is becoming more acidic and fresher, which means there’s less of minerals and carbonate needed for shell formation.

The shellfish which may now be at risk include mussels and clams that need minerals in the water to form their shells and skeletons.

If emissions of carbon dioxide are not curbed, the researchers conclude “the Arctic ecosystem may be at risk,” because the acidification of the seawater and resulting damage to shellfish could affect other marine life and fisheries.

During their studies on board the CCGS Louis St. Laurent, researchers documented a “rapid” drop in the levels of calcium carbonate, a compound used to produce shells and bones, in the top 50 metres of the surface waters in the Beaufort Sea.

Research carried out in the Svalbard Islands off Norway’s northern coast also suggests Arctic seawater is likely to reach corrosive levels within 10 years.

The seawater will then start to dissolve the shells of mussels and other shellfish, according to Professor Jean-Pierre Gattuso, of Centre National de la Recherche Scientifique.

A little shellfish eaten by baleen whales, salmon, herring and various seabirds would be at risk, he said, and its disappearance would have a major impact on the entire marine food chain.

By 2100, the entire Arctic Ocean will be “corrosively acidic,” he said.

Acidification happens faster in the Arctic Ocean because cold water absorbs more of the greenhouse gas carbon dioxide than warm water.

When carbon dioxide dissolves in seawater, it turns into into carbonic acid, which causes the oceans to become more acidic.

NUNATSIAQ NEWS, 20 November 2009. Article.

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