A laboratory experiment led by researchers at Stanford University found that brief physical contact with a healthy, genetically identical coral fragment can help a bleached coral begin recovering.
The team paired 10 bleached fragments of the branching coral Pocillopora damicornis with healthy fragments from the same genetic individual. Five pairs touched, while the others were kept a few millimeters apart. All five bleached corals that made contact regained their color within seven weeks; none of the separated fragments recovered.
How contact may aid recovery
When genetically identical coral tissues meet, they can fuse and form tiny channels between them. Researchers observed beneficial algae moving from the healthy fragment into the bleached one through these connections. The algae provide corals with much of the energy they need to live and grow. Transfer began within three days, and a few days of contact appeared sufficient to start the recovery process.
The study involved a small number of fragments from one species in controlled laboratory conditions, so it remains unclear whether the approach will work on natural reefs or across other coral species. It also relies on access to genetically matched healthy corals, which may limit its use at large scale.
The findings suggest physical contact could offer a new avenue for coral restoration research. If adapted beyond the laboratory, methods that help corals regain beneficial algae may complement wider efforts to support reef recovery.
