Thursday, June 2, 2011

Bubbling sea signals severe coral damage this century

Findings from a "natural laboratory" in seas off Papua New Guinea suggest that acidifying oceans will severely hit coral reefs by the end of the century.

Carbon dioxide bubbles into the water from the slopes of a dormant volcano here, making it slightly more acidic.

Coral is badly affected, not growing at all in the most CO2-rich zone.

Writing in journal Nature Climate Change, the scientists say this "lab" mimics conditions that will be widespread if CO2 emissions continue.

The oceans absorb some of the carbon dioxide that human activities are putting into the atmosphere.

This is turning seawater around the world slightly more acidic - or slightly less alkaline.

This reduces the capacity of corals and other marine animals to form hard structures such as shells.

Projections of rising greenhouse gas emissions suggest the process will go further, and accelerate.

"This is the most realistic experiment done to date on this issue," said Chris Langdon, a coral specialist from the Rosenstiel School of Marine and Atmospheric Science in Miami, US.

"So I don't have any qualms about believing that what we found will apply in other parts of the world." (read more)