Figure 2.

Variation in coral thermal tolerance. (a) Total phenotypic variation plotted as the number of coral individuals with a given ED50 (bin size = 0.1°C), coloured by nursery as in (b). (b) For each nursery (ordered by latitude; abbreviations as in figure 1), coloured points and probability density functions show ED50 values for each colony, black diamonds and error bars show the mean ± s.d., and boxplots show the median, interquartile range (IQR) and range of values within 1.5 * IQR. The grand mean is shown by the dashed vertical line. Nurseries that do not share a letter have significantly different mean ED50 values (p < 0.01). The black ‘+’ in the RR nursery indicates the one colony dominated by Durusdinium. (c) Adjusted ED50 values, after subtracting variation among nursery environments from total phenotypic variation; used to estimate the genetic (and genotype by environment) component of thermal tolerance. This approximately normal distribution is shown scaled to the per cent of individuals with a given ED50_adj (bin size = 0.1°C). (Online version in colour.)