"There were a lot of table corals present that went right up to the threshold from the last big storm, and then suddenly nothing above it," said Connolly. "They even followed the predicted trends from the reef crest to the reef back."
The researchers say that more severe storms, by themselves, would probably not pose a large threat to reefs. "Corals are adapted to life in stormy seas. Even the vulnerable species are quite stable when they're young," said Connolly. "They also tend to grow and mature quickly, so the species can recover before the next big storm arrives."
However, one effect of the increased production of greenhouse gases is an increase in the acidity of the ocean. This is likely to reduce the stability of coral reefs, and amplify the damage done by tropical storms in coming decades. Other effects of global warming could limit the capacity of the reefs to bounce back from periods of high wave forces, according to the researchers. For example, episodes of unusually hot temperatures can cause corals' cells to become toxic, or bleached. Another problem is overfishing, which can deplete the fish that eat dead coral and keep the reef clear for the next generation of corals.
"Regardless of whether we think of more severe storms as a looming threat or just the ramping up of a natural cycle, one thing is certain," said Connolly. "To predict how coral reefs will look under different future scenarios, and to plan accordingly, we needed to know exactly how wave forces impact who lives and who dies on the reef. These new models provide us with that essential tool."