Figure 4
From: Exposure history determines pteropod vulnerability to ocean acidification along the US West Coast
The changes in pteropod calcification depicted as a proportional glow, at the range of in situ conditions from 12 different stations characterized by the difference in carbonate chemistry. The regression line from a general linear model with logit-link and beta error distribution indicates positive correlation between aragonite saturation (Ωar) and proportional glow. Pteropods coming from high in situ Ωar demonstrate high glow of calcein in their shell, shown also visually in Fig. 5a and 5b Vertical lines indicate groupings based on the cluster analysis of stations; Cluster Group 1 (Ωar < 0.8; stations 35 and 104), Cluster Group 2 (0.8 < Ωar < 1; stations: 47, 108, 26, 38, 99), and Cluster Group 3 and 4 (Ωar > 1.2; stations: 28, 37, 106, 105, 113). Error bars indicate ± 1.0 standard errors. The average in situ Ωar of three groupings identifies two aragonite saturation state thresholds with respect to proportional glow; Ωar > 1.2 and Ωar < 0.8. Error bars indicate ± 1.0 standard errors, N = 96 (Table S3). Proportional glow and Ωar are related through the following equation: ln (% glow/(1-% glow)) = b0 + b1*(Ωar) = −4.34( ± 0.19 s.e.) + 5.07( ± 0.18 s.e.)* Ωar.
