BRENDAN TREMBATH: Marine scientists say they’ve been given an unprecedented look at what high levels of carbon dioxide can do to undersea landscapes.
They’re studying a highly volcanic region off Papua New Guinea where a tropical reef is being smothered by the gas.
They say the impact on the reef is a warning sign for countries around the world to reduce carbon emissions.
Josh Bavas reports.
JOSH BAVAS: Deep below the surface of Papua New Guinea’s east coast are huge cracks in the ocean floor.
The volcanic activity is leaching high levels of carbon dioxide into localised pockets of the reef in Milne Bay.
Report co-author Janice Lough from the Australian Institute of Marine Science says the carbon is radically changing the tropical reefs.
JANICE LOUGH: The paper’s titled ‘Winners and Losers’ but I’m afraid there’s far more losers than there are winners.
One of the beauties of tropical coral reefs is just their amazing bio-diversity. It’s not just about coral. There’s hundreds and thousands of different organisms that live on coral reefs.
The example at Milne Bay in Papua New Guinea illustrated what might happen in the future where you end up with much fewer corals of different types.
JOSH BAVAS: It’s the first time a tropical reef has been studied for this purpose outside the lab.
She says the closer to the carbon dioxide seepage, the less diverse the fish and coral species and more acidic the water.
Coral growth rates in these regions dropped about 30 per cent.
JANICE LOUGH: They went from what we would think was a lovely looking coral reef with lots of different types of coral, down to basically a reef that was dominated by massive boulder-like corals. There was a lot of sea grasses and there was a lot of macro algae or seaweed.
JOSH BAVAS: The report says if human carbon emissions continue at the current growth rate oceans around the world would see similar results within a century.
This morning a British newspaper published estimates from the International Energy Agency saying carbon dioxide emissions rose by 1.6 gigatonnes in the last year.
Ben McNeil from the University of New South Wales says the results of this reef study aren’t surprising.
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Josh Bavas, ABC Radio, 30 May 2011. Full article and audio.
