Cool-edge populations of the kelp Ecklonia radiata under global ocean change scenarios: strong sensitivity to ocean warming but little effect of ocean acidification

Damon Britton (Lead / Corresponding author), Cayne Layton, Craig N. Mundy, Elizabeth A. Brewer, Juan Diego Gaitán-Espitia, John Beardall, John A. Raven, Catriona L. Hurd

    Research output: Contribution to journalArticlepeer-review

    1 Citation (Scopus)
    18 Downloads (Pure)

    Abstract

    Kelp forests are threatened by ocean warming, yet effects of co-occurring drivers such as CO2 are rarely considered when predicting their performance in the future. In Australia, the kelp Ecklonia radiata forms extensive forests across seawater temperatures of approximately 7-26°C. Cool-edge populations are typically considered more thermally tolerant than their warm-edge counterparts but this ignores the possibility of local adaptation. Moreover, it is unknown whether elevated CO2 can mitigate negative effects of warming. To identify whether elevated CO2 could improve thermal performance of a cool-edge population of E. radiata, we constructed thermal performance curves for growth and photosynthesis, under both current and elevated CO2 (approx. 400 and 1000 µatm). We then modelled annual performance under warming scenarios to highlight thermal susceptibility. Elevated CO2 had minimal effect on growth but increased photosynthesis around the thermal optimum. Thermal optima were approximately 16°C for growth and approximately 18°C for photosynthesis, and modelled performance indicated cool-edge populations may be vulnerable in the future. Our findings demonstrate that elevated CO2 is unlikely to offset negative effects of ocean warming on the kelp E. radiata and highlight the potential susceptibility of cool-edge populations to ocean warming.

    Original languageEnglish
    Article number20232253
    Number of pages11
    JournalProceedings of the Royal Society B: Biological Sciences
    Volume291
    Issue number2015
    Early online date17 Jan 2024
    DOIs
    Publication statusPublished - 31 Jan 2024

    Keywords

    • multiple drivers
    • ocean acidification
    • ocean warming
    • phenotypic plasticity
    • physiology
    • thermal performance curves

    ASJC Scopus subject areas

    • General Immunology and Microbiology
    • General Biochemistry,Genetics and Molecular Biology
    • General Environmental Science
    • General Agricultural and Biological Sciences

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