Scientists Are Giving Coral Reefs Underwater Umbrellas
Monday, October 5, 2026198 words3 minutes2076 reads
A Florida research team tested 20 underwater shades over communities of two Atlantic brain coral species. The experiment took place from August to November 2024 at Newfound Harbor in the Florida Keys. The shades reduced the amount of sunlight reaching coral by 60%.
The test happened during a serious marine heat wave. Sea temperatures were above the Florida Keys bleaching threshold of 30.5°C for at least 61 days. Shaded corals showed less bleaching, and some that had already turned pale recovered colour after the shades were added.
Corals depend on microscopic algae that live in their cells. Heat and strong sunlight can damage this relationship. But the exact reason for colour change is still uncertain. An independent scientist noted that the paler unshaded corals may have changed the amount of chlorophyll in their algae, rather than losing algae faster. The study also could sample only the edges of corals, not the sunniest tops.
The shades do not cool seawater and cannot cover all reefs. The shades may protect high-priority corals during heat waves. This includes large or rare corals. Researchers still need to study long-term effects, such as whether shaded corals stay stronger against disease and can reproduce.
