Stanford Study Finds Bleached Corals Can Recover Fully Within Weeks by Touching Healthy Neighbors
Marine ecologists at Stanford report in Science Advances that bleached corals recovered within eight weeks after coming into contact with healthy neighbors that shared their symbiotic algae, a result researchers say could inform efforts to restore reefs damaged by marine heat waves.
The finding comes against steep losses. Roughly 84.4% of the world's coral reefs suffered bleaching-level heat stress during the last major marine heat wave, which ran from January 2023 to September 2025, and more than half of global coral coverage present in the 1950s has already been lost, according to figures in the reporting.
In the Stanford experiments, bleached coral placed in contact with healthy coral recovered in just eight weeks. Control corals did not show the same recovery. The recovery appears to work through the transfer of Symbiodiniaceae, the photosynthetic algae that live in coral tissue and supply the animals with much of their energy. When heat stress causes corals to expel those algae, the colonies turn white and can starve.
"This incredible new result — that fast and full recovery is possible in bleached coral — can inspire solutions that eventually may be scalable," Fiorenza Micheli, a marine ecologist with Stanford's Center for Ocean Solutions and a co-author of the study, told the journal Nature.
The algae-sharing behavior was described as a surprise discovery. Researchers and conservationists are pursuing several other approaches at the same time. At-risk coral sampled from Hawaii has been successfully deep-frozen and revived, and scientists are also working on the selective breeding of heat-tolerant corals and the cultivation of protected coral nurseries. According to the reporting, coral-to-coral contact could accelerate those efforts rather than replace them.
The study was published in Science Advances; the account of the work, including Micheli's comments to Nature, was carried by Gizmodo.