Fig 1.
Trial 1 mimicking current and future winter conditions and Trial 2 mimicking current and future summer conditions. Light blue flasks correspond to PCO2 ~ 500 ppm treatments and grey flasks to PCO2 ~ 1000 ppm treatments. Additional green flasks were used to study zooxanthellae density inside Cotylorhiza tuberculata polyps.
Table 1.
Temperature (T), pH (pHT25), Dissolved Oxygen (DO), total alkalinity (AT) and PCO2 in the six experimental treatments.
Fig 2.
Cotylorhiza tuberculata ephyrae and statoliths measurements.
A. Ephyrae of Cotylorhiza tuberculata. BD body diameter. Scale bar = 500 μm. B. Ephyrae marginal lappets and rhopalium. Scale bar = 100 μm. C. Rhopalium with statocyst containing statoliths inside. Scale bar = 50 μm. D. Statoliths. Scale bar = 20 μm.
Fig 3.
Population growth by budding, mortality and, strobilation of Cotylorhiza tuberculata polyps under tested temperatures (18, 24 and 30°C) and pH levels (ambient and future).
A, B, C. Percentage of growth of polyps by asexual reproduction (budding). D, E, F. Accumulate percentage of polyp mortality. G, H, I. Accumulate percentage of strobilation. Light blue for ambient pH conditions (PCO2 ~ 500 ppm) and dark blue for future pH conditions (PCO2 ~ 1000 ppm). Error bars are standard deviation. Grey bands are standard error.
Table 2.
Generalized estimating equations model (GEEGLM) and statistical significance of the fixed effects in explaining the variation of the number of polyps.
Table 3.
Number of polyps, number of dead polyps and number of released ephyrae counted at the beginning and at the end of the experiment.
Fig 4.
Diameter of ephyrae released under the different temperature (24°C and 30°C) and pH (ambient and future) treatments.
Light blue for 24°C and pH 7.99, dark blue for 24°C and pH 7.71, light red for 30°C and pH 8.01 and dark red for 30°C and pH 7.73. Error bars represent standard deviation (SD).
Table 4.
Summary of results of the linear mixed-models analysis of the ephyrae diameter (n = 24), number of statoliths (n = 13) and statolith volume (n = 13).
Fig 5.
Number of statoliths per rhopalium (A) and volume of statoliths (μm3) (B) under the different temperature (24°C and 30°C) and pH (ambient and future) treatments. Light blue for 24°C and pH 7.99, dark blue for 24°C and pH 7.71, light red for 30°C and pH 8.01 and dark red for 30°C and pH 7.73. Error bars represent standard deviation (SD).
Fig 6.
Malformed ephyrae released at the end of the experiment 2.
A. Ephyra from the ‘Present day’ treatment at 24°C and pH 7.99 without malformations. B. Malformed ephyra from ‘RCP8.5 temperature only’ treatment at 30°C and pH 8.01. Note the irregular distribution of zooxanthellae and the lack of crystals inside the rhopalium. C. Malformed ephyra from ‘RCP8.5 temperature and pH’ treatment at 30°C and pH 7.73. Note the low zooxanthellae content and the lack of rhopalium. D. Malformed ephyrae from ‘RCP8.5 pH only’ treatment at 24°C and pH 7.71.
Table 5.
Number of ephyrae analyzed per treatment, malformed ephyrae and the different kinds of malformations observed (lack of arms, lack of well-developed rhopalium and lack of statoliths inside the statocyst).
Fig 7.
Zooxanthellae density (mm2) within the polyps of Cotylorhiza tuberculata under different temperatures (18, 24 and 30°C) and pH levels (ambient and future).
Circle for 18°C, triangle for 24°C and rhombus for 30°C. Grey for ambient pH and black for future pH. Error bars show standard deviation (SD).
Table 6.
Summary of results of the linear mixed-models analysis of the zooxanthellae density (mm2) (n = 122).