



Rising acidity levels threaten ocean's food chain, study finds



The tiny snails, known as ‘‘sea butterflies’’, live in the seas around Antarctica and are left more vulnerable to predators and disease as a result of having thinner shells, scientists say.

The study presents rare evidence of living creatures suffering the results of ocean acidification caused by rising carbon dioxide levels from fossil fuel burning, the British Antarctic Survey said in a statement.

‘‘The finding supports predictions that the impact of ocean acidification on marine ecosystems and food webs may be significant.’’

The tiny snail, named for two wing-like appendices, does not necessarily die as a result of losing its shell, but it becomes an easier target for fish and bird predators, as well as infection.

This trend may have a follow-through effect on other parts of the food chain, of which they form a core element.

The world’s oceans absorb more than a quarter of man-made carbon dioxide emissions, which lower the sea water pH.

Since the beginning of the industrial era, our oceans have become 30 per cent more acidic, reaching an acidity peak not seen in at least 55 million years, scientists say.

Scientists discovered the effects of acidification on the sea butterflies from samples taken around the Scotia Sea region of the Southern Ocean in February 2008.




"The corrosive properties of the water caused shells of live animals to be severely dissolved and this demonstrates how vulnerable pteropods are," said lead author Nina Bednarek, from the NOAA.







If CO2 levels continue to rise in the future, surface waters could be almost 150 per cent more acidic by the end of this century, which has not been experienced for more than 20 million years.

Reuters, AFP

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