Researchers at Queensland University of Technology have discovered a three-phase biological process that allows coral fragments to reattach to reefs, offering new insights for global restoration efforts. The study, published in Royal Society Open Science, highlights species-specific differences that affect attachment speed and strength. This finding could help predict which corals will recover best in damaged ecosystems.
Coral reefs worldwide are declining due to environmental stresses, making the reattachment of broken fragments crucial for recovery. A team led by Dr. Brett Lewis from QUT's School of Earth and Atmospheric Sciences examined fragments from three species—Montipora mollis, Pocillopora verrucosa, and Acropora millepora—to uncover the attachment mechanism.
"Coral reefs are declining globally, and their recovery often depends on broken fragments reattaching and growing but that process isn't as simple as it sounds," Dr. Lewis said. "Even after decades of coral research, we still don't fully understand how fragments attach or how to make restoration efforts more effective."
Using advanced microscopy, the researchers identified a three-phase sequence. First, fragments respond to contact with an immune reaction, transforming tissues in a process Dr. Lewis described as "almost like flipping yourself inside out." Second, they anchor using new soft tissue. Third, a specialized appendage extends to build skeleton onto the reef substrate, creeping forward while sterilizing pathogens.
Species differences emerged in the appendage's structure: Montipora mollis features a larger, more complex one, enabling faster and stronger attachment, while Pocillopora verrucosa's thinner appendage leads to slower, weaker bonds. Mesenterial filaments aid preparation by digesting unnecessary tissues, enhancing resilience during stress.
The collaborators included Professor Peter Prentis, Associate Professor Luke Nothdurft, Dr. Crystal Cooper from the University of Western Australia, and Professor David Suggett from the University of Technology Sydney. Supported by Australia's Research Training Program and the Reef Restoration and Adaptation Program with the Great Barrier Reef Foundation, the study advances targeted restoration by predicting species performance in specific environments.
"By understanding the attachment processes and their underlying cellular and skeletal differences between species, we can better target corals for restoration and predict which corals will thrive in specific environments and grow fastest," Dr. Lewis said.