Monday, September 22, 2008

Coral reefs endangered even with current CO2 emissions

Current levels of Carbon dioxide (CO2) in the atmosphere are 380 parts per million, which is 100 ppm more compared to pre-industrial levels. What is even more alarming is the fact that CO2 levels are constantly increasing, mainly because of fossil fuels burning. CO2 is harmful greenhouse gas, mainly responsible for climate change, and global warming. But climate change isn't the only potential danger caused by increased CO2 levels as the latest scientific study showed that even the CO2 levels that can be called modest by climate change standards can have devastating effect on many marine ecosystems, because of ocean acidification.

This study based on computer simulations of ocean chemistry showed that ocean acidification could devastate coral reefs and many other marine ecosystems even if atmospheric carbon dioxide stabilizes at 450 ppm, a level well below that of many climate change forecasts. According to chemical oceanographer Long Cao " even if atmospheric CO2 stabilizes at the current level of 380 ppm, fewer than half of existing coral reef will remain in such an environment. If the levels stabilize at 450 ppm, fewer than 10% of reefs would be in waters with the kind of chemistry that has sustained coral reefs in the past."

Even current levels of CO2 have devastating effect on corals

CO2 has particularly negative impact on ocean since once atmospheric CO2 gets absorbed by the oceans' surface water it produces carbonic acid. Carbonic acid makes certain carbonate minerals dissolve more readily in seawater; one of these carbonate minerals is also aragonite that is mineral needed for growth of not only corals but many other marine organisms. No aragonite in surrounding water means there is no chance for coral to build coral reefs, and is really one way ticket to their extinction.

Cao also added that "at atmospheric CO2 levels as low as 450 ppm, large parts of the Southern Ocean, the Arctic Ocean, and the North Pacific would experience a rise in acidity that would violate US Environmental Protection Agency water quality standards." Under these conditions the shells of not only corals but many other marine organisms would dissolve.

And beautiful coral reefs that have been on our planet for many millions of years could become nothing but a memory in not so far future because they lack ability to cope with these new changes cause with the man-made global warming. This sad destiny doesn't look very likely only for corals but for many other marine organisms too. Many marine ecosystems could soon be brought to the very edge of extinction.

No comments:

Post a Comment