Acidic oceans: a major environmental hazard.
by Sébastien GERBAULT
Scientists have issued yet another alarming verdict on the state of the seas. Acidity is now threatening a vast array of sea-life.
In February 2007, at the yearly meeting of the American Association for the Advancement of Science, in San Francisco, marine experts delivered a most disquieting verdict on the increase of oceanic acidity. According to them, increased atmospheric emissions of carbon dioxide (one of the main greenhouse gases driving climate change) is causing the world's oceans to become more and more acidic.
Oceanic chemistry has been changing for some time now. Scientists have been issuing such warnings for decades. According to them, the acidity of the oceans has increased 30% since industrialisation began in the 19th century. They predict that, unless carbon dioxide (CO2) emissions are reduced, a 150% increase of the oceanic acidity rate is to be expected by 2100.
The carbon dioxide in the atmosphere is absorbed by the ocean, and then reacts with sea-water to produce carbonic acid. This acid consumes the carbonate that many marine creatures use to build their shells and mineral structures.
Coral reefs are among the organisms most severely hit: corrosive waters undermine their skeletal structures, which in turn undermines the marine ecosystem and harms other species.
According to Charlie Veron, of the Australian Institute of Marine Science, more than half of the existing coral reefs will be exposed to such waters by 2100.
Reducing carbon dioxide emissions is vital to preserve life in the oceans. Marine scientists have been striving to warn the general public, industrialists and politicians alike - so far, to no avail.
"Acid oceans threatening marine food chain, experts warn," www.nationalgeographic.com 17 February 2007.
“Acid oceans spell doom for coral,” www.bbc.co.uk 29 August 2004.
“Acidic oceans threaten marine food chain,” The Guardian 29 September 2005.