As sea surface temperatures increase, many reef-building coral species are shifting their ranges poleward into subtropical waters. However, at higher latitudes, conditions are less favorable for growth and survival due to strong seasonal temperature fluctuations and high productivity-driven turbidity. How reef-building corals physiologically adapt to these combined stresses in such marginal habitats remains poorly known. Understanding these mechanisms is essential for predicting how warming-driven species range-shift will affect coastal ecosystems and the services they provide.

For this study, I propose to quantify the combined impact of temperature stress and light attenuation (turbidity-induced) on the key physiological traits of corals across a latitudinal gradient to understand how corals cope with environmental challenges across their distribution. I propose to use Duncanopsammia peltata as a model system because it inhabits both tropical Indo-Pacific and higher-latitude southern China (including Hong Kong) where it is expanding its range. I propose replicating temperature stress experiments on corals under different light attenuation conditions to measure how extreme temperature and turbidity together influence the upper and lower thermal tolerance limits (indicated by photosynthesis rate and photosynthetic capacity) and the nutritional energy balance (indicated by heterotrophy level) across latitudinal gradients.

The findings of this project will significantly improve our understanding of how corals cope with multiple stressors and adapt as they move poleward under ocean warming. The results can potentially help identify resilient coral colonies for transplantation in marginal habitats in Hong Kong, supporting crucial ecosystem services like fisheries productivity and coastal protection under climate change.