COULD corals survive ocean acidification against the odds? That’s the hope raised by reefs found to be thriving in naturally acidified waters.

Corals use the carbonate ions in water to build their skeletons from calcium carbonate. But ocean acidification caused by climate change reduces the available carbonate ions. Lab studies suggest that this leaves corals unable to grow and survive. The few known reefs living in naturally acidified water also tend to be unhealthy.

So Kathryn Shamberger of the Woods Hole Oceanographic Institution in Massachusetts and her colleagues were surprised to find that coral reefs around the Palau archipelago in the west Pacific were dense and diverse – even though the pH of the water and the amount of carbonate were unusually low (Geophysical Research Letters, doi.org/qnj).

This suggests that the corals have a way to calcify in more acidic waters, says Philip Munday at James Cook University in Brisbane, Australia, or that they have adapted to low carbonate levels.


Working out just how they do this will be important in understanding the likely impacts of ocean acidification on coral communities elsewhere, he says.

This article appeared in print under the headline “Pacific coral happy as water acidity rises”