Coral may survive global warming, but not CO2 increase

[LAP]

Article publié le 20 août 2004

Source : DIVERNET

 

Corals could adapt to the higher sea temperatures caused by global warming, but increased levels of carbon dioxide will increase the acidity of the ocean.

 

The good news is that corals may be able to adapt and survive the predicted rise in ocean temperatures caused by global warming. Researchers studying the impact of temperature changes on Pacific corals before, during and after El Nino, have found that some are able to adapt by forming a symbiotic relationship with heat-resistant algae.

 

Corals which are unable to adapt will be wiped out, so reefs will change dramatically, according to the studies, reported in New Scientist magazine.

 

The not-so-good news is that the increased levels of 'greenhouse gas' carbon dioxide (CO2) will alter the acidity of the oceans. Researchers at the Royal Society are currently investigating the implications of excess CO2 being absorbed into the oceans and forming carbonic acid. Over time, this process is anticipated to raise the overall acidity of the oceans. The consequences for marine life are unknown, but scientists fear that the outcome will prove disastrous.

 

The skeletal structure of hard corals is calcium carbonate, and increased acidity appears to reduce the amount of calcium carbonate available in seawater. With an estimated extra 20-25 million tons of CO2 entering the oceans every day, significant changes to acidity levels, and to marine life, are predicted to take place in the next 100 years.

[Piezit@]

Intéressant cet article!

Il est possible que les coraux s'adaptent au rechauffement de l'eau mais il ne faut pas oublier que le rechauffement climatique provoque aussi une accélération de la dissémination d'épidemies qui peuvent toucher des espèces jusqu'alors épargnées.

En ce qui concerne l'augmentation du taux de CO2, il diminue en effet la calcification par diminution de la concentration en ions CO32-.