This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: High sea temperatures driven by the climate crisis damage corals, bleaching them ghostly white and killing them. While restoration of dead reefs is possible, it's difficult and expensive, and restored corals are vulnerable to future heat waves.
Finding ways to stop or slow the damage to existing reefs is crucial. Now scientists think they've found a way to protect some especially vulnerable Caribbean corals: umbrella-like shades. Shading can't cool the water, but it prevents UV and irradiance damage, which makes heat damage to corals worse.
"Heat-related coral bleaching is probably the biggest threat to reefs worldwide, and we absolutely have to address climate change to have any hope of reefs as we know them existing in the future," said Dr. Karen Neely of Nova Southeastern University, lead author of the article in Frontiers in Marine Science. "Solutions like shading can offer temporary protection on small scales.
"The 2023 coral bleaching event in Florida essentially wiped out branching corals, and at some inshore sites had a devastating impact on brain corals. This study stemmed directly from that event: we wanted to provide proof of concept for tools to save targeted corals in similar future events." In the summer of 2024, Neely and her team set up 20 custom-made shades over 10 different colonies of two species of brain coral, Pseudodiploria clivosa and Colpophyllia natans, at Newfound Harbor in the Florida Keys. They also selected 20 matching corals to act as controls.
The umbrella-like shades, made of pipes with nylon cloths attached, were temporarily fixed to the seabed with cord and floated 30 cm (12 inches) over each shaded coral. They reduced light by 60%. Divers visited every two weeks to track color changes and take tissue biopsies from the corals to monitor the algae living inside the corals' tissues.
Corals have a symbiotic relationship with these algae: the coral provides the algae with a home and the algae provide the coral with most of its nutritional needs. Algae also lend corals their color, so when corals turn white under heat stress, we know that the relationship has broken down and the coral is starving. Although the heat stress measured at Newfound Harbor that summer was the second-highest on record, the shaded corals lost less color than expected—and the differences were greatest during the most intense periods of thermal stress.
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