Coral growth, retraction, defense, and regenerative strategies revealed by live microCT

Understanding how corals build and remodel their skeletons is key to
explaining reef resilience, yet most insights come from static imaging.
Using longitudinal live microCT, we tracked the same coral colonies over
weeks to months at micrometer resolution. Coral skeleton formation is not
a uniform accretion process but a dynamic integration of multiple
programs, including vertical and horizontal patterned growth, previously
undescribed defensive wall-building against competitors, exploratory edge
behavior with reversible expansions and retractions, and skeletal
regeneration favoring rapid, imprecise yet effective matrix expansion.
Time-resolved imaging links colony-scale growth to microscale events,
showing that all modes depend on balances between fusion of skeletal
granules and layered matrix deposition, guided by tissue pre-patterning.
Beyond corals, this framework generalizes to studying skeletal dynamics
across diverse biomineralizing organisms.