Stanford researchers found that severely bleached corals could recover within seven weeks after brief physical contact with healthy, genetically identical coral fragments.
In a small laboratory experiment, researchers compared ten pairs of coral fragments, each containing a healthy fragment and a bleached fragment from the same original coral:
➡️ All five bleached fragments touching their healthy counterparts recovered completely within seven weeks.
The key was the transfer of beneficial algae, which provide much of a coral’s energy.
All five bleached fragments separated from their counterparts by just a few millimeters died.
Follow-up experiments showed that a week of contact…and sometimes only five days…was enough to initiate recovery, even when the fragments were subsequently separated.
Genetically identical coral fragments can fuse their tissues, creating connections through which beneficial algae and nutrients move. Researchers observed algae entering the bleached fragments within three days. Once established, the algae multiplied rapidly, helping restore the coral’s energy supply.
The finding offers a promising direction for coral-restoration research, but it is not yet a practical reef-wide treatment: supplying each damaged coral with a healthy, genetically identical partner would be difficult.
The team plans to investigate whether algae can be delivered without requiring tissue contact. The important distinction is that bleached corals are not necessarily dead, and restoring their symbiotic partners may help them recover.
Reference:
Collins, D. S., et al. (2026). “Rapid coral bleaching recovery via symbiont transfer from healthy corals.” Science Advances, 12(42).