A University of Hawaii researcher has come up with a new explanation for how acidification of the ocean disrupts coral growth.

Higher acidity interferes with the transfer of hydrogen ions, or protons, between the seawater and the coral tissue, which ultimately disrupts the coral’s ability to create a skeleton, says Paul Jokiel of the Hawaii Institute of Marine Biology.

In his “proton flux hypothesis,” Jokiel contends that the calcification of coral skeletons is dependent on the passage of hydrogen ions between the water and the coral tissue. Lowered calcification rates create weakened coral skeletons, leaving them susceptible to breakage, and decreasing protection, he says.

“This hypothesis provides new insights into the importance of ocean acidification and temperature on coral reefs,” he says. “The model is a radical departure from previous thought, but is consistent with existing observations and warrants testing in future studies.”

Previous studies focused on the relationship between coral growth and levels of a mineral called aragonite, a form of calcium carbonate that corals use to build their skeleton.

Jokiel’s research findings appear in the July issue of the Bulletin of Marine Science.

The oceans are becoming more acidic due to the absorption of carbon from the atmosphere. Carbon dioxide levels in the atmosphere have been rising since the Industrial Revolution.