ORCID

Abstract

There is growing evidence that reef-building corals can acclimate to novel and challenging thermal conditions. However, potential trade-offs that accompany acclimation remain largely unexplored. We investigated physiological trade-offs in colonies of a globally abundant coral species (Pocillopora acuta) that were acclimated ex situ to an elevated temperature of 31 °C (i.e., 1 °C above their bleaching threshold) for six years. By comparing them to conspecifics maintained at a cooler temperature, we found that the energy storage of corals was prioritized over skeletal growth at the elevated temperature. This was associated with the formation of higher density skeletons, lower calcification rates and consequently lower skeletal extension rates, which entails ramifications for future reef-building processes, structural complexity and reef community composition. Furthermore, symbionts were physiologically compromised at 31 °C and had overall lower energy reserves, likely due to greater exploitation by their host, resulting in an overall lower stress resilience of the holobiont. Our study shows how biological trade-offs of thermal acclimation unfold, helping to refine our picture of future coral reef trajectories. Importantly, our observations in this six-year study do not align with observations of short-term studies, where elevated temperatures were often associated with the depletion of energy reserves, highlighting the importance of studying acclimation of organisms at relevant biological scales.

Publication Date

2024-11-01

Publication Title

Science of the Total Environment

Volume

949

ISSN

0048-9697

Acceptance Date

2024-07-05

Deposit Date

2024-07-23

Funding

AR and JS acknowledge the funding of the Helmholtz Institute for Functional Marine Biodiversity (HIFMB) at the University of Oldenburg, Niedersachsen, Germany. HIFMB is a collaboration between the Alfred-Wegener-Institute, Helmholtz-Center for Polar and Marine Research, and the Carl-von-Ossietzky University Oldenburg, initially funded by the Ministry for Science and Culture of Lower Saxony and the Volkswagen Foundation through the \u201CNieders\u00E4chsisches Vorab\u201D grant program (grant number ZN3285). PJS acknowledges support via startup funding by the Institute of Chemistry and Biology of the Marine Environment (ICBM, University of Oldenburg). Funding for the initial research that produced the corals used in this study was provided by the German Academic Scholarship Foundation. We thank M.Sc. Tabea Platz for her assistance in the wet laboratory during physiological experiments and Esther L\u00FCdtke as well as Irini Kioupidi for support in coral tissue processing. Thanks to Prof. Gabriele Gerlach and Susanne Wallenstein for providing laboratory space and equipment to perform live physiology and skeletal density measurements. We thank Dr. Mareen M\u00F6ller for her support in producing and rearing the corals used in this study. We thank Dr. Laurie J. Raymundo (University of Guam Marine Laboratory) for providing temperature data from the \u201Chome\u201D reef of our corals. Research was conducted under the permit of the DEPARTMENT OF AGRICULTURE DIVISION OF AQUATIC AND WILDLIFE RESOURCES (DAWR) and MPA APPLICATION SPECIAL REQUEST (Section 63123 of Title 5, Guam Code Annotated GCA) to PJS. Corals were collected under the Special License for The Collection of Coral, issued to UOGML by DAWR under section 63123 of Title 5, GCA, and exported under permission of CITES issued by the US Fish and Wildlife Service (export # 15US62023B/9). AR and JS acknowledge the funding of the Helmholtz Institute for Functional Marine Biodiversity (HIFMB) at the University of Oldenburg, Niedersachsen, Germany. HIFMB is a collaboration between the Alfred-Wegener-Institute, Helmholtz-Center for Polar and Marine Research, and the Carl-von-Ossietzky University Oldenburg, initially funded by the Ministry for Science and Culture of Lower Saxony and the Volkswagen Foundation through the \u201CNieders\u00E4chsisches Vorab\u201D grant program (grant number ZN3285 ). PJS acknowledges support via startup funding by the Institute of Chemistry and Biology of the Marine Environment (ICBM, University of Oldenburg). Funding for the initial research that produced the corals used in this study was provided by the German Academic Scholarship Foundation . We thank M.Sc. Tabea Platz for her assistance in the wet laboratory during physiological experiments and Esther L\u00FCdtke as well as Irini Kioupidi for support in coral tissue processing. Thanks to Prof. Gabriele Gerlach and Susanne Wallenstein for providing laboratory space and equipment to perform live physiology and skeletal density measurements. We thank Dr. Mareen M\u00F6ller for her support in producing and rearing the corals used in this study. We thank Dr. Laurie J. Raymundo (University of Guam Marine Laboratory) for providing temperature data from the \u201Chome\u201D reef of our corals.

Keywords

Climate change, Host-symbiont interaction, Metabolic switching, Ocean warming, Physiological plasticity, Pocillopora, Temperature, Animals, Acclimatization/physiology, Anthozoa/physiology, Coral Reefs

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STOTEN-D-24-04649_Revised_manuscript_R1_Final_21Jun_withfigures.docx (2813 kB)

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