Fig. 3.

Coral bleaching responses during heat tolerance assessments before and after the coral microbiome transplantation experiments. a, b Effects of temperature (“29 °C” vs. “34 °C”) on the bleaching score of corals from sites of low and high environmental variability (“LowVar” and “HighVar”) are compared. c, d Next, data shows that the handling procedure during inoculation had no impact on the bleaching score of corals (“I”, inoculation group vs. “C”, sterile-filtered seawater (FSW) control group). Subsequently, e, f the temperature effects on the bleaching scores of the recipient group and the FSW control group are shown. Plots visualize ∆-bleaching score data (i.e., the difference of tissue color intensity at end–start of each experimental part). Swarm plots (left side plot) show raw data points and Cumming estimation plots (right) depict the effect sizes as the mean differences between the treatment groups using Cohen’s d and a 95% confidence interval. Significant differences are indicated by connecting lines (p < 0.001***, < 0.01**, < 0.05* from generalized linear/linear mixed effect models). Vertical error bars, 95% CI; N, individuals per treatment group; branching coral, Pocillopora; massive coral, Porites; light green, “HighVar” west shore corals; orange, “HighVar” reef flat corals; teal, “LowVar” east shore corals; colored circles represent the donor inoculum used: light green, “HighVar” Pocillopora donor; orange, “HighVar” Porites donor