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Within-population variability in coral heat tolerance indicates climate adaptation potential

Lookup NU author(s): Dr Adriana Humanes Schumann, Liam Lachs, Elizabeth Beauchamp, Professor John BythellORCiD, Emeritus Professor Alasdair Edwards, Dr Pawel PalmowskiORCiD, Dr James Guest



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Coral reefs are facing unprecedented mass bleaching and mortality events due to marine heatwaves and climate change. To avoid extirpation, corals must adapt. Individual variation in heat tolerance and its heritability underpin the potential for coral adaptation. However, the magnitude of heat tolerance variability within coral populations is largely unresolved. We address this knowledge gap by exposing corals from a single reef to an experimental marine heatwave. We found that double the heat stress dosage was required to induce bleaching in the most-tolerant 10%, compared to the least-tolerant 10% of the population. By the end of the heat stress exposure, all of the least tolerant corals were dead, whereas the most-tolerant remained alive. To contextualize the scale of this result over the coming century, we show that under an ambitious future emissions scenario, such differences in coral heat tolerance thresholds equate to up to 17 years delay until the onset of annual bleaching and mortality conditions. However, this delay is limited to only 10 years under a high emissions scenario. Our results show substantial variability in coral heat tolerance which suggests scope for natural or assisted evolution to limit the impacts of climate change in the short-term. For coral reefs to persist through the coming century, coral adaptation must keep pace with ocean warming, and ambitious emissions reductions must be realized.

Publication metadata

Author(s): Humanes A, Lachs L, Beauchamp EA, Bythell JC, Edwards AJ, Golbuu Y, Martinez HM, Palmowski P, Treuman A, van der Steeg E, van Hooidonk R, Guest JR

Publication type: Article

Publication status: Published

Journal: Proceedings of the Royal Society B

Year: 2022

Volume: 289

Issue: 1981

Online publication date: 31/08/2022

Acceptance date: 08/08/2022

Date deposited: 14/09/2022

ISSN (print): 0962-8452

ISSN (electronic): 1471-2954

Publisher: The Royal Society Publishing


DOI: 10.1098/rspb.2022.0872


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Funder referenceFunder name
725848Commission of the European Communities
NE/S007512/1Natural Environment Research Council (NERC)