Coral reefs rely upon the highly optimized coral–Symbiodiniaceae symbiosis, making them sensitive to environmental change and susceptible to anthropogenic stress. Coral bleaching is predominantly attributed to photo-oxidative stress, yet nutrient availability and metabolism underpin the stability of symbioses. Recent studies link symbiont proliferation under nutrient enrichment to bleaching; however, the interactions between nutrients and symbiotic stability are nuanced. Here, we demonstrate how bleaching is regulated by the forms and ratios of available nutrients and their impacts on autotrophic carbon metabolism, rather than algal symbiont growth. By extension, historical nutrient conditions mediate host–symbiont compatibility and bleaching tolerance over proximate and evolutionary timescales. Renewed investigations into the coral nutrient metabolism will be required to truly elucidate the cellular mechanisms leading to coral bleaching.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This project is jointly funded through the Australian Institute of Marine Science and the Australian Government’s National Environmental Science Program (NESP). L.A.M. acknowledges additional support from an AIMS@JCU PhD scholarship and a NESP Tropical Water Quality Hub grant. C.R.V. acknowledges support from King Abdullah University of Science and Technology (KAUST). The authors gratefully acknowledge Hillary Smith for her help with Figure 1.