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Underwater lab experiment a window to future of the world

by Anna Osborne

The very thought that microscopic organisms which live underneath the frigid sea ice in Antarctica could fundamentally alter our way of life is baffling.

Yet this very fact is driving a bold new research project. Dr Donna Roberts and 11 of her colleagues, including divers and technicians, are about to embark on an epic underwater science experiment in Antarctica.

The team will replicate future Southern Ocean conditions, increasing the amount of CO² in the water with four bio-dome structures, and study the effect on the ocean’s smallest, yet arguably, most vital organisms.

About 1500kg of CO², or 69 gas bottles, will be used in the four-month experiment which will take place just near Casey Station from November.

The experiment is using the Free Ocean CO² Enrichment (FOCE) prototype and is the first of its kind to be undertaken in natural polar environs.

“There have been many experiments where CO² has been studied in a lab environment,” said Dr Roberts, who is the experiment’s chief investigator, in collaboration with the Australian Antarctic Division’s Dr Jonny Stark.

“It’s the first time the lab has been taken to the ecosystem, rather than the ecosystem to the lab. We want to turn up the CO² and observe the Southern Ocean’s response.

“It is the first natural polar community-wide experiment and it will be a pointer to what will happen in the rest of the world.”

The four Perspex pods, the size of coffee tables, will allow natural light and food to filter through and will house hundreds of species including animals and plants, bacteria and protists (single-cell organisms) and, importantly, shell makers. There is no threat to fish, penguins or seals, Dr Roberts explains, as the pods include large animal restrictors.

“It’s not often thought about but the sea floor is the nursery of fish stocks,” Dr Roberts said.

The sea floor is the epicentre of marine biodiversity, and ocean acidification poses a very real and serious threat.

Dr Roberts said ocean acidification happened when CO² dissolves in seawater. It increases the acidity and decreases the availability of carbonate, a combination that makes it more difficult for many marine organisms to construct their calcium carbonate shells.

“With things like corals and shell makers, the higher the acidity of the water the more their shells dissolve,” she said.

“They are the critical link between the plankton and the commercial fish stocks.”

The ocean represents 96 per cent of the Earth’s living space and contains 80 per cent of Earth’s living organisms.

‘What’s worrying researchers such as Dr Roberts is ... the “warm beer effect”.’

What is worrying researchers such as Dr Roberts is polar regions are acidifying at twice the rate of tropical regions, with cold water absorbing more CO² than warm water. This is also known as the “warm beer effect”.

“You’ll notice that if you are at a barbecue and have a beer, wine or soft drink it goes flat in the heat, but if it’s in the fridge it’s still fizzy and that’s because cold water absorbs more CO² than warm water,” Dr Roberts said.

“That’s why polar regions are hit hard and hit first with acidity problems.”

Dr Roberts grew up in the Huon Valley in southern Tasmania and has always been intrigued by the water.

Her interest led her to pursue a career in science where she is now a Senior Research Fellow at the Antarctic Climate and Ecosystems Cooperative Research Centre (ACE CRC).

The idea to create the first underwater polar-wide community came in 2009 when she first met the prototype’s inventor, Bill Kirkwood, from the Monterey Bay Aquarium Research Institute in California. The prototype had already been used in a deep water experiment in California.

Since then Dr Roberts has worked towards assessing the polar sea-floor community securing an ARC LEIF grant ($150,000), along with supporting funds from the University of Tasmania ($50,000) and ACE CRC ($50,000).

In July the team will carry out its first in-water test at Kettering in Tasmania before heading out to Casey Station in November.

“Most of our planet is water and half of the oxygen we breathe comes from ocean plants,” Dr Roberts said.

“So every second breath you take is courtesy of the ocean – people don’t realise that. And more CO² has an impact on organisms, which will have an impact on our lives.”