Will some coral reefs be able to adapt to rapidly changing conditions in Earth's oceans? If so, what will these reefs look like in the future? As the ocean absorbs atmospheric carbon dioxide (CO2) released by the burning of fossil fuels, its chemistry is changing. The CO2 reacts with water molecules, lowering ocean pH (making it more acidic) in a process known as ocean acidification.

This process also removes carbonate, an essential ingredient needed by corals and other organisms to build their skeletons and shells.

Now, in time for World Oceans Day on June 8, scientists are studying coral reefs in areas where low pH is naturally occurring to answer questions about ocean acidification, which threatens coral reef ecosystems worldwide. 

Palau reefs dodge ocean acidification effects

One such place is Palau, an archipelago in the far western Pacific Ocean. The tropical, turquoise waters of Palau's Rock Islands are naturally more acidic due to a combination of biological activity and the long residence time of seawater in their maze of lagoons and inlets.

Seawater pH within the Rock Island lagoons is as low now as the open ocean is projected to reach as a result of ocean acidification near the end of this century.

A new study led by scientists at the Woods Hole Oceanographic Institution (WHOI) found that coral reefs in Palau seem to be defying the odds, showing none of the predicted responses to low pH except for an increase in bio-erosion--the physical breakdown of coral skeletons by boring organisms such as mollusks and worms.

A paper reporting the results is published today in the journal Science Advances.