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In Acidifying Ocean, 'Dissolving' Shells Portend Marine Disaster

- Common Dreams staff

Ocean acidification, caused by human-induced rising CO2 levels, is hitting the base of the marine food chain in the Antarctic and stands as an ominous sign for widespread impacts on marine life.

Image: NOAA's Pacific Marine Environmental Library According to research published Sunday, the increasingly acidified Antarctic is dissolving the shells of sea snails, called pteropods.

The Independent reports that "The researchers believe it could be a harbinger of worse things to come."

"Pteropods are an important food source for fish and birds as well as a good indicator of ecosystem health," the Independent reports Geraint Tarling of the British Antarctic Survey in Cambridge as saying.

Explaining the ocean acidification / pteropod shell dissolving connection, New Scientist reports:

The most vulnerable animals are those, like pteropods, that build their shells entirely from aragonite, a form of calcium carbonate that is very sensitive to extra acidity. By 2050, there will be a severe shortage of aragonite in much of the ocean.

Aragonite is still relatively plentiful in most of the ocean, but Tarling suspected that some regions might already be affected by shortages.

He visited the Southern Ocean near South Georgia where deep water wells up to the surface. This water is naturally low in aragonite, meaning the surface waters it supplies are naturally somewhat low in the mineral – although not so much so that it would normally be a problem. Add in the effect of ocean acidification, however, and Tarling found that the mineral was dangerously sparse at the surface.

"It's of concern that they can see it today," says Toby Tyrrell of the National Oceanography Centre in Southampton, UK.

Aragonite-depleted regions are still rare, but they will become widespread by 2050, says Tarling. The polar oceans will change fastest, with the tropics following a few decades after. "These pockets will start to get larger and larger until they meet," he says.

The Daily Mail adds that Professor Justin Ries of the University of North Carolina, who reviewed the findings

said the corrosion of Southern Ocean pteropods documented in the study has yet to trigger a 'butterfly effect' - the idea small changes in a system's initial conditions, such as the flapping of a butterfly's wings, may trigger large scale alterations in that system.’

But he added: ‘However, the study suggests the dual impacts of ocean acidification and global warming render the flapping more ominous by the day.’