Figure 4
From: Coralline algal physiology is more adversely affected by elevated temperature than reduced pH
Variation in solar radiation and Fv/Fm during the experiment.
(a) The variation in daily light exposure (mol quanta m−2 d−1) and maximum photochemical efficiency of photosystem II, Fv/Fm, measured at dusk daily for rhodoliths (b), articulated alga (c) and CCA (d). Lines in (a) are grey for rhodoliths, black for the articulated alga and dashed for CCA. Symbols in (b–d) are white circles for control treatments (ambient pH and 30 °C), grey squares for the low pH treatment (pH 7.9 and 30 °C), black squares for the thermal stress treatment (ambient pH and +2 °C [32 °C]) and white squares for the interaction between thermal stress and reduced pH (pH 7.9 and +2 °C [32 °C])). The dashed lines in (b–d) indicate Fv/Fm values before the initiation of the corresponding treatment. The black horizontal bars at the bottom of the figure illustrate the beginning and end of each 10-day treatment. The symbols represent mean values ± SEM (n = 4–10 per experimental day).
