Study claims ocean food chain threatened by greenhouse gas

A study by Australian scientists has found rising concentrations of acid in the Southern Ocean caused by greenhouse gases are damaging the ability of some sea creatures to form shells.

Dr Will Howard is one of the study’s authors and he has said the findings were the first evidence from nature, rather than a laboratory, that the acidification of the Southern Ocean will potentially have a big 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,” said Dr Howard, whose study was funded by the Federal Government’s Department of Climate Change.

The study is published today in the journal Nature Geoscience and compares 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 modern creatures had shell weights 30 to 35 per cent lower than their pre-industrial forebears.

Implications of the study cover 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 about the increasing amounts of carbon dioxide being absorbed by the oceans as greenhouse gas emissions, such as carbon dioxide, soar, for some years now.

The growing greenhouse gas concentrations in the atmosphere come principally from the burning of fossil fuels and land clearing.

When carbon dioxide dissolves in the ocean it forms a weak acid . This is known as acidification. In 2008, Howard and his fellow Australian marine scientists issued a warning about ocean acidification saying its impacts would be observed first in the Southern Ocean, which surrounds Antarctica.

Their warning was 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.

Dr Howard and other leading Australian scientists are arriving in Copenhagen for a global scientific congress aimed at updating political leaders on the latest science on climate change.

Bob Ewing, Digital journal, 9 March 2009. Article.

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