White syndrome is a coral disease associated with major losses of branching corals on the Great Barrier Reef.
The disease produces sharply defined areas of exposed white skeleton as living coral tissue dies. It has affected many hard-coral colonies, with branching forms often suffering extensive tissue loss because a large surface area can be exposed quickly.
Scientists use “white syndrome” as a field description for a group of rapidly progressing coral diseases showing similar signs; the precise causes can involve different pathogens and environmental conditions. This makes it different from a single universally identified organism or one simple disease mechanism.
White syndrome is also distinct from coral bleaching. Bleaching is the loss of symbiotic algae and color while tissue may remain alive, whereas white syndrome involves tissue mortality and exposed skeleton. Both can damage reefs but are not interchangeable terms.