Fig. 3

EEAs in laboratory experiment, by corals from the control condition (green plots), heat condition (red plots) and low light condition (blue plots). The boxplots represent α-Glucosidase activity (α-Glu, nmol MUF mg⁻¹ AFDW h⁻¹) in octocorals (a) and hexacorals (b), Alkaline phosphatase activity (APA, nmol p-NP mg⁻¹ AFDW h⁻¹) in octocorals (c) and hexacorals (d), and Leucine-aminopeptidase activity (LAP, nmol AMC mg⁻¹ AFDW h⁻¹) in octocorals (e) and hexacorals (f.). AFDW, ash-free dry weight; EEAs, extracellular enzymatic activities. Sarcophyton and Lobophytum are octocorals while Stylophora and Turbinaria are hexacorals. The control condition is 26 °C and an irradiance of 220 µmol photons⁻¹ m⁻² s⁻¹; the heat condition is 30 °C and an irradiance of 220 µmol photons⁻¹ m⁻² s⁻¹; the low light condition is 26 °C and an irradiance of 50 µmol photons⁻¹ m⁻² s⁻¹. Asterisks indicate significant differences between the control and stress conditions for each species (* for p < 0.05; ** for p < 0.01; *** for p < 0.001; **** for p < 0.0001). Significant differences between species within each condition are indicated by letters: plain letters (a, b) for the control, letters with apostrophes (a′, b′) for heat stress, and letters with double apostrophes (a″, b″) for low light. For all enzymes and conditions tested, EEAs were significantly higher in both hexacorals compared to both octocorals.