Polyp size predicts metabolic rates across diverse tropical coral species

Body size is a fundamental driver of metabolism, yet it remains unclear whether colonial organisms such as corals conform to the universal ¾-power scaling law. As climate change accelerates metabolic demands, characterizing these scaling relationships is essential to identifying which species are most physiologically vulnerable to environmental shifts. Here, we test whether coral polyp morphological traits can predict aerobic metabolism across a diverse range of reef-building species. We examine relationships between respiration and polyp biovolume, surface area, and corallite width, finding isometric scaling with biovolume and slight positive allometry with surface area, with both exponents close to one. Using median corallite width, we further extrapolate our model to theoretically predict per-polyp respiration for 727 coral species from a publicly available trait database.