Southern Ocean acid a threat to marine life

West Australian
Monday 9/3/2009 Page: 13

Rising concentrations of acid in the Southern Ocean caused by greenhouse gases are damaging the ability of some sea creatures to form shells, posing a serious threat to marine life, a study by Australian scientists has found. One of the study's authors, Will Howard, said the findings were the first evidence from nature, rather than a laboratory, that the acidification of the Southern Ocean was having an impact on marine life.

"The potential knock-on effects pose significant implications for the oceanic food chain and the findings are a worrying signal of what we can expect to see elsewhere in the future," Dr Howard, whose study was funded by the Federal Government's Department of Climate Change, said.

The study, to be published today in the journal Nature Geoscience, compared the shells of microscopic marine animals, called forams, taken from the Southern Ocean with shells from similar animals preserved in sediments dating back to pre-industrial times. The scientists found the modern creatures had shell weights 30-35% lower than their pre-industrial forebears.

The study has implications for a wide range of sea life whose shells or skeletons could be damaged or deformed by rising acid levels, including krill, the main food source for whales. Scientists have been raising the alarm for several years about the increasing amounts of carbon dioxide being absorbed by the oceans as greenhouse gas emissions, such as carbon dioxide, soar.

The growing greenhouse gas concentrations in the atmosphere come mainly from the burning of fossil fuels and land clearing. As more and more carbon dioxide dissolves in the ocean it forms a weak acid, a process called acidification. Dr Howard and his fellow Australian marine scientists last year issued a warning about ocean acidification, saying its impact would be observed first in the Southern Ocean, which surrounds Antarctica.

They warned ocean acidification could have "significant ramifications for human communities dependent on coastal resources in Australia, the Indian Ocean and South Pacific region". The problem has since received global attention.

The release of the study comes as the campaign to overhaul the Federal Government's key climate change policy escalates this week as big greenhouse polluting companies and their lobbyists target politicians representing voters in coal mining, steel and aluminium towns. The campaign will warn MPs and senators of job losses and risks to regional economies.

Yesterday, 24 environmental and community groups, including the Australian Conservation Foundation and Greenpeace, sent a letter to Prime Minister Kevin Rudd urging him to send the carbon pollution reduction scheme "back to the drawing board for urgent redesign".