Common Caribbean corals exhibit highly variable responses to future acidification and warming.

Area of Science:

• Marine Biology
• Climate Change Science
• Coral Reef Ecology

Background:

• Ocean acidification and warming pose significant threats to coral reefs globally.
• Caribbean coral species exhibit diverse physiological responses to environmental stressors.

Purpose of the Study:

• To investigate the independent and combined effects of ocean acidification and warming on Caribbean coral calcification and extension rates.
• To assess the resilience of four key coral species to projected climate change conditions.

Main Methods:

• A 93-day experiment exposed four Caribbean coral species (Siderastrea siderea, Pseudodiploria strigosa, Porites astreoides, Undaria tenuifolia) to varying levels of pCO2 (280-3300 µatm) and temperatures (28°C, 31°C).
• Calcification and linear extension rates were measured for each species under different treatment conditions.

Main Results:

• All coral species showed nonlinear declines in calcification with increasing pCO2.
• Warming significantly reduced calcification only in Pseudodiploria strigosa.
• Siderastrea siderea was the only species to maintain positive calcification in aragonite-undersaturated conditions.
• Natal reef environment did not influence coral responses to experimental treatments.

Conclusions:

• Siderastrea siderea exhibits the highest resilience to warming and acidification among the tested species.
• Pseudodiploria strigosa and Undaria tenuifolia demonstrated the lowest resilience.
• Coral responses to climate change stressors are species-specific, highlighting the complexity of reef futures.