Figure 1.
Impact of a range of pCO2 on: A. median hatching time; B. size of the juvenile at hatching (Experiment 1).
A significant logarithmic relationships was observed between pCO2 and hatching time of cocoons (F = 10.76, p<0.008) but not between pCO2 and juvenile size at hatching time within the range of tested pCO2 (F = 0.01, p<0.97).
Figure 2.
Impact of a range of pCO2 on the growth rate of newly hatched juveniles in presence of their photosymbiotic algae (9 days exposure; Experiment 3).
A significant logarithmic relationships was observed between pCO2 and juvenile growth rate (F = 7.84, p<0.019), the growth rate being 19% faster in the highest test pCO2 (27 k µatm) compared to the lowest (0.4 k µatm).
Figure 3.
Impact of a range of pCO2 on: A. number of eggs produced per female; B. number of eggs per cocoon; C. number of cocoon produced per female (experiment 4).
The number of eggs produced per female was 3 times higher in high compared to low pCO2 (27 k vs 0.4 k µatm) and a significant logarithmic relationship was observed between the two parameters (F = 8.36, p<0.016; Figure 3A). This was the consequence of an increased number of cocoon produced per female (significant logarithmic relationship, F = 7.79, p<0.02; Figure 3B) with no effect on the number of eggs per cocoon (non significant logarithmic relationship, F = 0.43, p<0.53; Figure 3C).
Figure 4.
Symsagittifera roscoffensis after a 24 h exposure to seawater with different pH (experiment 5).
Animals in the lower pH started to bleach.
Figure 5.
Summary of the impact of low pCO2 (27063 µatm) on S. roscoffensis life cycle.