Coral Species Near Moorea Bounced Back After 2019 Bleaching, But At A Reproductive Cost
At the beginning of 2019, mass bleaching devastated coral reefs around the French Polynesian island of Moorea, affecting more than 80 percent of Acropora coral in some areas. Just a few months later, marine biologists noticed that some of the bleached coral colonies seemed to have bounced back. By October 2019, they had regained their colorful algal symbionts and appeared completely healthy.
But as the adage goes, looks can be deceiving. In a new paper, scientists led by Sarah Leinbach, a graduate student at Auburn University in Alabama, show that even though the bleached coral colonies had a seemingly miraculous superficial recovery, they had lower energy stores and were producing fewer eggs than their unbleached counterparts.
Corals bleach when they expel the symbiotic algae that live in their cells, which provide them with food. “They’re losing these minuscule food factories that live in their tissues,” explains Leinbach. This forces the corals to draw from their energy stores to survive—energy they might otherwise use for reproduction. Leinbach and her colleagues don’t know how much longer these energetic and reproductive effects will last, though the group is dedicated to figuring it out. They completed follow-up surveys in November 2021 and are analyzing that data now.
Jacqueline Padilla-Gamiño, a marine biologist at the University of Washington who was not involved in the research, says this study’s strength is that it looked at how the coral colonies were faring months after the bleaching took place rather than measuring the immediate aftermath. “Sometimes it’s really hard to get a big picture on what it really takes for the corals to recover, and what is the impact on the future generations,” says Padilla-Gamiño. “I will be super interested to see what happened after two years.”
EDIT
https://grist.org/article/rumors-of-this-corals-survival-were-greatly-exaggerated/
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