Melting Arctic sea ice diluting water which puts food chain at risk The Irish Times - Friday, November 20, 2009

HONG KONG – Melting of Arctic sea ice due to global warming is diluting surface waters and this is endangering some species of shellfish which need minerals in the water to form their shells and skeletons, scientists have found.

In a paper published in Science , they warned that this has serious implications for ecosystems in the Arctic. “Organisms that are likely to be affected are from the family of pteropods, also mussels and clams on the sea floor,” said Fiona McLaughlin, research scientist at Canada’s Institute of Ocean Sciences’s department of fisheries and oceans. Pteropods are minute swimming sea snails.

“It puts the food chain at risk. These organisms are a food source for fish, that are a food source for seals and bears. The food chain in the Arctic is quite a short one, so it’s quite vulnerable,” Dr McLaughlin said. Meltwater from sea ice pours into the Canada Basin and researchers in Canada have been monitoring the quality of water in the basin, the largest freshwater reservoir in the world, since the late 1980s.

Dr McLaughlin said there was now sufficient evidence to show a fall in the concentration of aragonite, a mineral or calcium carbonate that is needed in shell formation. “Sea ice is so pure it has very few of these ions. It means that when we are melting this ice, which by its nature [is] more acidic, we are making surface waters more acidic.”

“The shells can’t maintain themselves . . . Instead of being a source of carbonate for these organisms to use, the surface waters are now corrosive to them,” she added. – (Reuters)