Tuesday, April 12, 2016

Ocean acidification already slowing coral reef growth


Public Release: 24-Feb-2016
Ocean acidification already slowing coral reef growth
Carnegie Institution

A team of scientists led by Carnegie's Rebecca Albright and Ken Caldeira performed the first-ever experiment that manipulated seawater chemistry in a natural coral reef community in order to determine the effect that excess carbon dioxide released by human activity is having on coral reefs. Their results provide evidence that ocean acidification is already slowing coral reef growth. Their work is published in Nature.

When we burn coal, oil, or gas, the resulting carbon dioxide is released into the atmosphere where it acts as a greenhouse gas. Greenhouse gases emitted by human activity don't just affect the atmosphere; they also have a negative impact on the world's oceans. This is partially due to overall warming caused by climate change. But also, over time, most of the carbon dioxide in the atmosphere is absorbed by the ocean, where it reacts with seawater to form an acid that is corrosive to coral reefs, shellfish, and other marine life. This process is known as 'ocean acidification'.

Coral reefs are particularly vulnerable to the ocean acidification process, because reef architecture is built by the accretion of calcium carbonate, called calcification, which becomes increasingly difficult as acid concentrations increase and the surrounding water's pH decreases. Scientists predict that reefs could switch from carbonate accretion to dissolution within the century due to this acidification process.


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