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Journal of Experimental Biology partnership with Dryad

The effects of a variable temperature regime on the physiology of the reef-building coral Seriatopora hystrix: results from a laboratory-based reciprocal transplant
Anderson B. Mayfield, Pei-Hsun Chan, Hollie M. Putnam, Chii-Shiarng Chen, Tung-Yung Fan

SUMMARY

To understand the effects of global climate change on reef-building corals, a thorough investigation of their physiological mechanisms of acclimatization is warranted. However, static temperature manipulations may underestimate the thermal complexity of the reefs in which many corals live. For instance, corals of Houbihu, Taiwan, experience changes in temperature of up to 10°C over the course of a day during spring-tide upwelling events. To better understand the phenotypic plasticity of these corals, a laboratory-based experiment was conducted whereby specimens of Seriatopora hystrix from an upwelling reef (Houbihu) and conspecifics from a non-upwelling reef (Houwan) were exposed to both a stable seawater temperature (26°C) regime and a regime characterized by a 6°C fluctuation (23–29°C) over a 12 h period for 7 days. A suite of physiological and molecular parameters was measured in samples of both treatments, as well as in experimental controls, to determine site of origin (SO) and temperature treatment (TT) responses. Only chlorophyll a (chl a) concentration and growth demonstrated the hypothesized trend of higher levels when exposed to a TT that mimicked SO conditions. In contrast, chl a, maximum dark-adapted quantum yield of photosystem II (Fv/Fm), and Symbiodinium ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcL), photosystem I (psI, subunit III) and phosphoglycolate phosphatase (pgpase) mRNA expression demonstrated significant TT effects. Specifically, levels of these response variables were higher in samples exposed to a variable temperature regime, suggesting that S. hystrix may acclimate to fluctuating temperatures by increasing its capacity for photosynthesis.

FOOTNOTES

  • Supplementary material available online at http://jeb.biologists.org/cgi/content/full/215/23/4183/DC1

  • FUNDING

    A.B.M. was funded by an international postdoctoral research fellowship from the National Science Foundation (NSF) of the United States of America (OISE-0852960), as well as an NSF East Asia and Pacific Summer Institutes (EAPSI) fellowship. The Journal of Experimental Biology provided funding to A.B.M. through a travel fellowship, and both the PADI Foundation and PADI Project Aware contributed funds to A.B.M. for conducting of laboratory analyses. Funds from the International Society for Reef Studies/Ocean Conservancy (ISRS/TOC) and the United States Environmental Protection Agency (FP917199) were awarded to H.M.P. Finally, intramural grants from NMMBA to T.-Y.F. funded the LBRT experiment, as well as the physiological analyses.

  • LIST OF ABBREVIATIONS

    apx1/APX1
    ascorbate peroxidase
    chl a
    chlorophyll a
    FSW
    filtered seawater
    Fv/Fm
    maximum dark-adapted quantum yield
    GCP
    genome copy proportion
    HSD
    honestly significant difference
    hsp70/HSP70
    heat shock protein-70
    ITS2
    internal transcribed spacer region 2
    LBRT
    laboratory-based reciprocal transplant
    PAR
    photosynthetically active radiation
    pgpase/PGPASE
    phosphoglycolate phosphatase
    psI/PSI
    photosystem I
    PSII
    photosystem II
    PTG
    photosynthesis-targeted gene
    rbcL/RBCL
    ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit
    RFLP
    restriction fragment length polymorphism
    ROS
    reactive oxygen species
    RT
    reverse transcription
    SA
    surface area
    SO
    site of origin
    TT
    temperature treatment
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