Healthy corals restore bleached neighbors' color after five days of contact
A new lab study by Stanford University scientists finds that simply placing healthy, colorful corals in contact with bleached counterparts is enough to bring the dying ones back from the brink. The research, published Wednesday in the journal Science Advances, could eventually pave the way for real-world interventions if it can be scaled. Эту информацию сообщает сайт Phys.org.
The team ran tests with pairs of cauliflower corals, finding five days of contact between healthy and bleached fragments was all it took for the latter to mount a spectacular recovery, at which point they could be safely pried apart. The key to the success of the method—informally dubbed "helping hands"—is the transfer of healthy photosynthetic algae, also known as symbionts, from which corals derive their color.
"It's stunning," lead author Daniel Collins told AFP about the outcome, recalling the "eureka moment" when he first saw positive results and rushed to his Ph.D. supervisor's office to share the news.
The experiments revealed important constraints: three days of contact was the minimum required for a bleached coral to begin to recover, and five ensured full recovery. They also had to be in direct contact—a few millimeters apart, and nothing significant happened. A major limitation was that the process only worked when the two corals shared the same genetic background, or "genet." Mixed-genet pairings resulted in the corals deploying stinging cells, a hostile response that can be likened to organ rejection in humans.
The biggest challenge will be translating an exciting lab finding into a real-world solution. "We likely will not be touching corals to each other on reefs," said Collins, noting the sheer size of reefs tends to preclude this option. However, it is possible to extract healthy symbionts and culture them—and the team is now thinking about ways to reintroduce them en masse to bleached coral.
