Ocean acidification reduces coral recruitment by disrupting intimate larval-algal settlement interactions

Authors

  • Christopher Doropoulos,

    Corresponding author
    1. School of Biological Sciences, University of Queensland, St Lucia, Qld 4072, Australia
    2. Australian Research Council Centre of Excellence for Coral Reef Studies, University of Queensland, St Lucia, Qld 4072, Australia
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  • Selina Ward,

    1. School of Biological Sciences, University of Queensland, St Lucia, Qld 4072, Australia
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  • Guillermo Diaz-Pulido,

    1. Australian Research Council Centre of Excellence for Coral Reef Studies, University of Queensland, St Lucia, Qld 4072, Australia
    2. Griffith School of Environment and Australian Rivers Institute, Nathan Campus, Griffith University, Nathan, QLD 4111, Australia
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  • Ove Hoegh-Guldberg,

    1. Australian Research Council Centre of Excellence for Coral Reef Studies, University of Queensland, St Lucia, Qld 4072, Australia
    2. Global Change Institute, University of Queensland, St Lucia, Qld 4072, Australia
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  • Peter J. Mumby

    1. School of Biological Sciences, University of Queensland, St Lucia, Qld 4072, Australia
    2. Australian Research Council Centre of Excellence for Coral Reef Studies, University of Queensland, St Lucia, Qld 4072, Australia
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E-mail: c.doropoulos@uq.edu.au

Abstract

Ecology Letters (2012) 15: 338–346

Abstract

Successful recruitment in shallow reef ecosystems often involves specific cues that connect planktonic invertebrate larvae with particular crustose coralline algae (CCA) during settlement. While ocean acidification (OA) can reduce larval settlement and the abundance of CCA, the impact of OA on the interactions between planktonic larvae and their preferred settlement substrate are unknown. Here, we demonstrate that CO2 concentrations (800 and 1300 μatm) predicted to occur by the end of this century significantly reduce coral (Acropora millepora) settlement and CCA cover by ≥ 45%. The CCA important for inducing coral settlement (Titanoderma spp., Hydrolithon spp.) were the most deleteriously affected by OA. Surprisingly, the only preferred settlement substrate (Titanoderma) in the experimental controls was avoided by coral larvae as pCO2 increased, and other substrata selected. Our results suggest OA may reduce coral population recovery by reducing coral settlement rates, disrupting larval settlement behaviour, and reducing the availability of the most desirable coralline algal species for successful coral recruitment.

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