To explain that, Grottoli and colleagues closely examined the bleached and healthy corals of the two species on the reef.
"We let them feed for one hour," Grottoli said. "Then we harvested them all, dissected each polyp and counted how many zooplankton each had eaten, how big they were and what species. That told us how much the coral had eaten."
Surprisingly, the researchers discovered that while the bleached Porites fed at its normal rate, bleached Montipora had increased its rate of feeding more than five-fold, allowing it not only to survive and repair but also replenish its internal energy reserves.
"We think that this means that coral like Montipora can switch how it gets its food so that it can sustain itself in a bleached state much longer than can corals like Porites," she said. "While bleached Porites is limited by how much energy reserves it has, bleached Montipora is not.
That's good news for Montipora and corals like it as the frequency, duration and intensity of warming events increases globally. But Grottoli warns that Montipora's resilience doesn't diminish the threat that bleaching events hold for the world's coral reefs. While it might survive while other species may not, on a global scale it is unlikely to re-colonize areas where less-resilient species died.
"Recent projections suggest that with the current rate of warming, as much as 60 percent of the world's coral reefs could be lost within the next 10 to 30 years," she said. "We have a delicately balanced ecosystem that is already highly stressed. It is very much interconnected and so far, we have royally messed it up."