There is increasing concern among scientists that ocean acidification, the so-called “evil twin” of climate change, could affect the functioning of whole marine ecosystems, and in particular, polar ecosystems.

This concern is underlined by the Antarctic Climate and Ecosystems Cooperative Research Centre’s (ACE CRC) newly launched Report Card: Southern Ocean Acidification.

Ocean acidification is the name given to the decrease in the pH level of the ocean as it takes up more anthropogenic carbon from the atmosphere.

In recent years research has shown that this change in ocean chemistry decreases the availability of carbonate ions used by tiny organisms at the base of the marine food chain to build calcium carbonate shells or skeletons.

The Carbon Program leader at the ACE CRC, Professor Tom Trull, said it was now known that that the impacts of ocean acidification went beyond these organisms.

“Recent work by the Australian Antarctic Division has shown that Antarctic krill show impaired embryonic development at high CO2 levels," Professor Trull said.

“Changing krill distribution could impact on predators such as whales, seals and penguins.

“And we also know that the impacts are not negative for all organisms. Some may grow more rapidly in an elevated CO2 environment, but we don't understand why because we don't yet understand the mechanisms behind this change."