MEPS 438:119-128 (2011)  -  DOI: https://doi.org/10.3354/meps09271

ABSTRACT: Reef-building corals provide critical ecosystem functions but are under pressure from a range of stressors, and there is a growing need to understand how environmental factors affect the physiological condition of corals. This study explored the relationships between tissue quality (i.e. energy content per unit surface area) and light intensity, water flow velocity, temperature, colony size and competition for 4 common coral species. A formal model selection procedure revealed that different corals, even species that are closely related and morphologically similar, respond to their local environments in fundamentally different ways. Overall, colony size was the most consistent predictor of tissue quality, and the observed increase in tissue energy content with size may partially explain field observations of reduced mortality for large colonies. However, competitive interactions, light intensity, water flow and temperature also contributed to variation in tissue properties. Warming reduced the tissue quality of massive and foliose corals more than that of branching corals, despite the latter generally being recognised as more susceptible to thermal bleaching. These findings identify species- and habitat-specific responses to baseline environmental variables that can be used to anticipate shifts in coral health under environmental change.

KEY WORDS: Light intensity · Water flow · Colony size · Temperature · Competition · Bioenergetics · Statistical modelling · Model-average regression coefficient