Coral recovery after a burial event: insights on coral resilience in a marginal reef

Abstract

Scleractinian reef-building corals can lose their endosymbiotic photosynthetic dinoflagelates (Symbiodiniaceae) and bleach in response to drastic changes in environmental conditions, such as extreme temperature fluctuations and burial events. As bleaching episodes are becoming more frequent and intense worldwide, post-bleaching recovery is critical for coral resilience. We report an in situ experiment in which a previously monitored colony of the coral Siderastrea stellata was found detached, overturned, buried, and bleached (95% of its surface). We reattached the coral to the reef and documented its recovery during 6 months by quantifying its surface area and health condition using 3D models derived from structure-from-motion photogametry of videos obtained in the field. The coral showed the first signs of recovery from a bright-white bleached state within 2 days and fully recovered to a healthy-like state in roughly 1 month, demonstrating that the endosymbiotic algal community recovered fast. Understanding the mechanisms of this fast recovery in marginal reefs in which post-bleaching mortality of dominant reef-building corals like S. stellata is relatively low (< 10%) may provide insights on how reef-building corals will cope with future climate change.