Fig. 3. pH, carbonate, and calcium values of the ECM in the growing edge of S. pistillata microcolonies measured in the light (200 μmol photons m⁻¹ s⁻¹) and dark.

Box and whisker plots show single replicate measurements (○); the mean (●); the first, second (median; bold line), and third quartile (horizontal lines of the boxes); and respective whiskers (vertical lines spanning to the lowest and highest data point of all data, excluding outliers). Replicate numbers (n) represent separate microcolonies and are given on each graph. Horizontal dashed line, seawater values (CO₃²⁻, 196 ± 15 μmol kg⁻¹ seawater; pH_SW [NBS], 8.09 ± 0.01; Ca²⁺, 11 ± 0 mM).