"This is particularly significant given recently observed and predicted future changes in the temperature and acidity of our oceans ¬¬-- via global warming and rising atmospheric CO2 , respectively -- that will presumably have a significant impact on corals' ability to build their skeletons and construct their magnificent reefs," he said.
Corals are crucial to nearshore tropical ecosystems because the reefs they build are inhabited by tens of thousands of marine animals, plants, algae and bacteria that make up the coral reef ecosystem, which is one of the planet's most diverse, Ries said. But coral reefs also serve a more practical purpose: They absorb wave energy generated by hurricanes and other severe tropical storms.
"Ironically, the same factor that is likely causing such storms to increase in intensity ?global warming ?is also causing the corals to bleach (lose their symbiotic algae) and die, ultimately leading to the destruction of the coral reefs, which protect the coasts from these storms," Ries said. "All that being said, it is also important to note that the magnesium-calcium ratio of seawater changes only over millions of years and has no direct relationship to recent global warming and ocean acidification, which are believed to be at least partly human caused."
His team's experiments do, however, have significance with respect to global warming and ocean acidification, Ries said, because they reveal that although corals can adapt mineralogically to altered seawater chemistry, doing so slowed the corals' rate of growth by nearly 65 percent.
"This provides us with further evidence that corals are extremely sensitive to rapid environmental change, such as global warming," he said.