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Ocean-In-A-Box To Test Future CO2 Impact On Polar Environments

posted 13 Jan 2014, 14:03 by Mpelembe   [ updated 13 Jan 2014, 14:04 ]

A team of international scientists are preparing to test the effect of heightened CO2 levels in waters around Antarctica, to learn more about the impact of conditions expected over the next century. The researchers will be using technology that replicates forecast acidity levels to see how plants and animals respond.

CASEY STATION, ANTARCTICA (AUSTRALIAN BROADCASTING CORPORATION) -  A team of Australian and US scientists are preparing to test the effects of heightened levels of carbon dioxide (CO2) in the southern ocean around Antarcticato gain an early glimpse of the effect of predicted future conditions there.

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Climate change modelling indicates that cold polar waters will absorb more carbon dioxide than warmer waters, creating a more acidic environment. The researchers want an early look at what that will mean for the animal and plant life that those waters support.

"We're building a future ocean, a future box and we're going to turn the CO2 up inside it and see what happens to the entire community," said Dr Donna Robertsfrom the Antarctic Climate and Ecosystem Research Centre at the University of Tasmania.

That future ocean comes in the form of semi-enclosed underwater chambers that will placed beneath the Antarctic ice sheet. They will allow scientists to vary the CO2 concentration in the water without changing light or nutrient conditions.

Such chambers have been deployed in other parts of the world already by theMonterey Bay Aquarium Research Institute (MBARI) in California, but never in polar conditions.

"So we take sea water, we add some CO2 to it and change that pH and inject that into this chamber," said MBARI's Bill Kirkwood.

After sites for the chambers have been identified, the team's first task will be to deploy them beneath the Antarctic ice sheet.

"We drill a couple of series of holes through that and then we dive through that which gives us a really nice platform to work on to get under the ice and then deploy all the different bits of equipment that we've got to get down there," said theAustralian Antarctic Division's Glenn Johnstone.

Ocean acidification leads to a drop in the pH of seawater which leaves some marine organisms unable to grow hard shells, the researchers say. The more information they have, says Roberts, the better prepared scienists can be.

"In the open ocean for example there are things called terapods, they are baby snails that have a shell and they're being eaten away and they actually support the entire southern ocean food web," Roberts said.

The Australian-US team is not the only group of scientists concerned about the impact of acidification in polar waters. In 2012, a study by the British AntarcticSurvey (BAS) reported that ocean acidification caused by climate change is making it harder for creatures from clams to sea urchins to grow their shells. Led by Professor Llloyd Peck, the study said the trend is likely to be felt most in polar regions.

Modelling suggests that the impact of acidification, produced by excess carbon dioxide in the atmosphere, will reach a critical point in the Southern Ocean between 2040 and 2050 if current trends continue. Scientists fear the lower Ph level could make it harder for creatures to extract calcium carbonate - vital to grow skeletons and shells.

They hope the chamber experiments will provide a much clearer picture of what to expect.