"What's really interesting is just how quickly and violently the coral forcefully evicted its resident symbionts," Lewis said in a press release. "The H. actiniformis began ejecting the symbionts within the first two hours of us raising the water temperature of the system."
Once the algae are evicted, the coral turns completely white. If the algae loss is prolonged, the coral will die, but not without a fight.
Other research has found that H. actiniformis can be resilient, suffering algae-spewing bleaching events and then recovering.
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"Our observations suggest this resilience could be due to the rapid expulsion of the coral's algal symbionts during thermal stress, and could very well increase H. actiniformis's chance of survival during abnormally high sea temperatures," Lewis said.
Despite such survival skills, many corals can't handle the relentless heat and other stressors that they are often faced with now.
As Nothdurft said, "If the Symbiodinium is removed from the host and does not recolonize quickly, the corals can die."
He added, "Mass coral bleaching events are a concern for scientists globally with recent events on the Great Barrier Reef highlighting the threat of elevated water temperatures to the health of reef ecosystems."
Recent estimates suggest that over 90 percent of the Great Barrier Reef has been impacted by coral bleaching, which in turn can harm fish, turtles and other animals that live on and around reefs.