Rising carbon dioxide in the atmosphere is causing ocean acidification, leading to adverse impacts on shell-forming organisms such as sea urchins, cold water corals and plankton.

Around half of carbon dioxide generated by human activities such as burning fossil fuels is now stored in the world’s oceans, particularly the colder Southern Ocean surrounding Antarctica. This increases the acidity of the ocean, which limits the ability of marine organisms to form shells and other external structures.

Scientists at the Antarctic Climate and Ecosystems CRC in Hobart are studying a shellforming variety of plankton about the size of a sand grain to find out the effects of carbon dioxide fluctuations in the geological past.

They have found shells are lighter at times of high atmospheric carbon dioxide concentration, suggesting that shell-forming organisms in the Southern Ocean have already begun to experience the impacts of ocean acidification.

For more information: Australian GreenhouseOffice, Andrea Mettenmeyer,

Tel: +61 2 6274 1859, communications@greenhouse.gov.au