Figure 4
Effect of salinity on the growth of Indo-Pacific corals. (a) Replicate colonies of M. foliosa and Montipora sp. were cultured at high (42) and reduced (36.5) salinity levels for >2 months. The wet weight of each fragment was determined at three time points during the incubation period. The data were normalised to the corresponding initial measurement values. Data points indicate changes in the average weight of five replicate colonies per species and condition, error bars denote s.e.m. Lines correspond to theoretical model fittings as detailed in Supplementary Table S1. The death of M. foliosa replicates before the last weight determination is indicated by a dashed line. Asterisks indicate significant difference between the treatments below the corresponding experimental values (two sample t-test, *P<0.05 and **P<0.01). (b and c) Effects of salinity and temperature stress on the survival of Indo-Pacific corals. Replicate colonies of M. foliosa, Montipora sp. and P. lichen corals were acclimated to two salinity levels (42 and 36.5) at a constant temperature of 27.5 °C. The temperature remained unaltered for the control corals over the duration of the >3-month experiment (b). At time point 0, temperatures were slowly ramped up (0.5 °C per day) for the treatment group and corals were incubated at 32 °C until the end of the experiment (c). The graphs display the changes in colony surface covered by live tissue. The data points represent the average of four and five colonies per genotype for the control and temperature treatments, respectively. Error bars denote s.e.m. Lines correspond to the theoretical models as detailed in Supplementary Table S1. M. foliosa samples exposed to Sal 42 under high-temperature stress died before the 16-day measurements, which is indicated by the dashed line section of the corresponding fitting.
