Underwater Umbrellas Shield Corals From Heat

Marine heatwaves pose a significant threat to coral reefs worldwide, leading to bleaching events that occur with increasing frequency. In response, scientists in Florida have developed underwater shades, resembling parasols, to offer temporary protection to corals during periods of extreme heat.

During the summer of 2024, researchers fitted 40 brain coral colonies in the Florida Keys with these floating shades, suspended about 30 centimeters above them. The umbrellas primarily reduced intense sunlight and ultraviolet radiation, which exacerbate heat stress. This approach contrasts with direct water cooling.

Despite experiencing significant heat stress, some of the shaded corals showed signs of color recovery after the umbrellas were installed. In contrast, exposed corals became paler. However, the scientists emphasize that this method is a temporary fix, not a comprehensive solution for the global warming crisis.

Covering entire reefs is impractical, limiting the umbrellas' use to protecting specific, vulnerable corals during extreme heat events. The study highlights the ongoing challenge of scaling such interventions. The researchers stress that ultimately, long-term coral survival depends on global efforts to curb rising sea temperatures and limit marine heatwaves.