Table 1.
Summary of the research objectives of this study, the general approach, and coral metrics used to investigate each objective.
Fig 1.
In situ levels of (a) endosymbionts (Symbiodinium density x106 cm-2), (b) total chlorophyll (chl a + chl c, μg cm-2), (c) tissue protein (mg cm-2), and (d) tissue biomass (calculated via ash-free dry weight, mg cm-2) of naturally occurring P. damicornis colonies, with D. aruanus (n = 5) and without fish (n = 5) present. (*) denotes a significant difference between fish treatments, and error bars show S.E.
Fig 2.
Differences in mean (±SE) levels of (a) endosymbionts (Symbiodinium density x106 cm-2), (b) total chlorophyll (chl a + chl c, μg cm-2), and (c) tissue protein (mg cm-2) of naturally occurring S. hystrix colonies, with D. aruanus (n = 19) and without fish (n = 18) present during a coral bleaching event at Lizard Island. Colonies positioned at 1–3 m depth within four lagoonal sites with limited current activity. (*) denotes a significant difference between fish treatments, and error bars show S.E.
Fig 3.
Levels of (a-c) endosymbionts (Symbiodinium density x106 cm-2), (d-f) total chlorophyll (chl a + chl c, μg cm-2), (g-i) protein (mg cm-2), (j-l) tissue biomass (calculated via grams of ash-free dry weight mg cm-2) in experimental P. damicornis colonies, with D. aruanus for different temperature and fish treatments (ambient/fish: n = 9, ambient/no fish: n = 9, hot/fish: n = 10 and hot/no fish: n = 9) for three different experimental phases (Acclimation (25°C), Stress (temperature increased and held at 32°C for four weeks), and Recovery (temperature returned to 25°C). (*) denotes a significant difference between select comparisons fish treatments, and error bars show S.E. Refer to S6 Table for results of all 12 planned contrast per coral tissue components. Note difference in y-axis for panels C and F, to allow for visualization of variance between treatments. Data points per phase, temperature, and fish presence have been abbreviated to form 3 letter keys, as follows: A = acclimation, S = stress, R = recovery, A = ambient temperature, H = hot/bleaching temperature, F = fish present, N = fish absent. i.e. SHF = sample collected during stress phase of a hot temperature with fish present colony.
Table 2.
Linear mixed effect model of the effect of phase, temperature, and fish presence (D. aruanus) on experimental P. damicornis colonies for (i) Symbiodinium density, (ii) total chlorophyll density, (iii) total proteins (iv) and tissue biomass (as part of the manipulative thermal bleaching experiment), where coral colony was included as a random effect.
Fig 4.
Temporal changes in photosynthetic efficiency (FV/FM) of P. damicornis with (a and c) and without D. aruanus (b and d) under control (a and b) and heated (c and d) treatments. Data are presented for all phases of the experiment: Acclimation (days 1–7), Temperature Stress (days 8–37) and Recovery (days 38–66); and points and error bars show means and S.E. for n = 9 colonies per treatment group. Solid lines show best fit regression lines (for line equations regression coefficients see Table 3). Black fish symbols represent colonies with fish, and white symbols represent colonies without fish. Note different y-axis ranges were used for visual clarity of effects.
Table 3.
Comparison of regression models testing the effects of temperature (ambient: 25°C or hot: 32°C) and fish presence (fish or no fish) on P. damicornis photosynthetic efficiency (FV/FM), fitting the data through the means for colonies within treatments for the Acclimation and Stress experimental periods during the manipulative thermal bleaching experiment.
Akaike’s information criteria (AIC) and AIC differences (ΔAIC) were calculated per model selection practice [58–60]. See S8 Table for calculations with individual points yielding similar results as mean models (mean model results presented here).