Coral reefs may dissolve as pH drops

The world's coral reefs are at risk as rising carbon dioxide levels in the oceans is causing the pH to drop, says a new study.

Scientists at a conference on climate-change in Exeter yesterday heard that around 48% of all carbon dioxide emissions are being taken up by the sea.

Although this may delay global warming, experts believe that it will have a dramatic effect on marine life.

As carbon dioxide dissolves in water, some of it forms carbonic acid, which reduces the pH of the water and causes changes in a variety of other chemicals, such as alkalinity and calcium levels.

Marine invertebrates, such as corals, crustaceans and echinoderms rely on the presence of these chemicals in their water, and may not be able to uptake calcium effectively if carbon dioxide levels in the oceans continue to rise.

This may have a knock-on effect for other species, including fish which feed upon these invertebrates, and even the appearance of the marine ecosystem if keystone species, such as algal grazing echinoderms, are reduced in number.

A report from the BBC yesterday suggested that in the Red Sea, the critical point for corals could be just 30-70 years away.