Document Type

Article

Publication Date

2023

DOI

10.1002/ece3.10798

Publication Title

Ecology and Evolution

Volume

13

Issue

12

Pages

e10798 (1-20)

Abstract

Back-to-back marine heatwaves in 2016 and 2017 resulted in severe coral bleaching and mortality across the Great Barrier Reef (GBR). Encouragingly, some corals that survived these events exhibit increased bleaching resistance and may represent thermally tolerant populations that can better cope with ocean warming. Using the GBR as a natural laboratory, we investigated whether a history of minimal (Heron Island) or severe (Lizard Island) coral bleaching in 2016 and 2017 equates to stress tolerance in a successive heatwave (2020). We examined the genetic diversity, physiological performance, and trophic plasticity of juvenile (<10 cm) and adult (>25 cm) corals of two common genera (Pocillopora and Stylophora). Despite enduring greater cumulative heat stress (6.3°C week-1 vs. 5.6°C week-1), corals that experienced the third marine heatwave in 5 years (Lizard) exhibited twice as high survival and visual bleaching thresholds compared to corals that had not experienced significant bleaching in >10 years (Heron). Surprisingly, only one shared host-Symbiodiniaceae association was uncovered between locations (Stylophora pistillata-Cladocopium "C8 group") and there was no genetic overlap in Pocillopora-Cladocopium partnerships, suggesting turnover in species composition from recent marine heatwaves. Corals within the species complex Pocillopora that survived the 2016 and 2017 marine heatwaves at Lizard Island were the most resilient, exhibiting three times greater calcification rates than conspecifics at Heron Island. Further, surviving corals (Lizard) had distinct isotopic niches, lower host carbon, and greater host protein, while conspecifics that had not experienced recent bleaching (Heron) had two times greater symbiont carbon content, suggesting divergent trophic strategies that influenced survival (i.e., greater reliance on heterotrophy vs. symbiont autotrophy, respectively). Ultimately, while corals may experience less bleaching and survive repeated thermal stress events, species-specific trade-offs do occur, leaving open many questions related to the long-term health and recovery of coral reef ecosystems in the face of intensifying marine heatwaves.

Rights

© 2023 The Authors.

This is an open access article under the terms of the Creative Commons Attribution 4.0 International License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited.

Data Availability

Article states: "Original data and all R-scripts generated for this study can be found on https://github.com/imkristenbrown/Coral-ecological-memory-from-heatwaves. Sequence data were deposited on GenBank under accession numbers OR887551 -OR887595 and OR837528 - OR837623."

Original Publication Citation

Brown, K. T., Genin, A., Mello-Athayde, M. A., Bergstrom, E., Campili, A., Chai, A., Dove, S. G., Ho, M., Rowell, D., Sampayo, E. M., & Radice, V. Z. (2023). Marine heatwaves modulate the genotypic and physiological responses of reef-building corals to subsequent heat stress. Ecology and Evolution, 13(12), 1-20, Article e10798. https://doi.org/10.1002/ece3.10798

ORCID

0000-0002-4867-0164 (Radice)

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