The effects of ocean acidification, caused by atmospheric carbon dioxide dissolving in the ocean, will be a focus of research at Antarctica’s Davis station this summer.

Scientist Dr Andrew Davidson says that the research project will investigate the effects of ocean acidification on Antarctic marine microbes (phytoplankton, protozoa and bacteria).

“These organisms play a vital role in the marine food web and they moderate global climate change by absorbing carbon dioxide and producing dimethylsulphide, a natural chemical that influences cloud formation,” he said.

“Ocean acidification is a recently identified side-effect of increasing amounts of carbon dioxide in the atmosphere. Carbon dioxide dissolves in seawater, forming carbonic acid. The resulting increase in ocean acidity interferes with the formation of calcium carbonate, a major structural component of the shells of many important planktonic organisms.

“The colder an ocean is, the more carbon dioxide it can dissolve. Therefore the impacts of ocean acidification will appear first in the icy Southern Ocean,” said Dr Davidson.

Microbial communities from the sea ice zone around Davis station will be incubated in large tank-like 'minicosms' under different carbon dioxide concentrations. This study aims to determine the effect of ocean acidification on the structure and function of Antarctic microbial communities and the potential ramifications for the food web and carbon balance in the Southern Ocean.

“This work will contribute to our understanding of the expected changes in these microbial communities due to global warming, sea ice retreat and increased amounts of ultraviolet radiation.

“Ultimately, ocean acidification will have important consequences for marine ecosystems and the human communities that depend on them for survival, so it’s critical that we have the information that we need in order to understand and respond to this looming problem,” Dr Davidson said.

Scientists, including Dr Davidson, and personnel destined for Australia’s Antarctic stations will depart today on the first voyage of the Aurora Australis for the summer shipping season.

Voyage One will spend five weeks at sea, visiting Australia’s Casey and Davis stations to deliver supplies and relieve some staff who have spent the winter in Antarctica.

The first flight of the Australian Antarctic Division’s A319 Airbus from Hobart to Wilkins Runway, near Casey station, is scheduled for 11 November.