Rapid evolution fuels transcriptional plasticity to ocean acidification

Area of Science:

• Marine Biology
• Environmental Science
• Genomics

Background:

• Ocean acidification (OA) poses a threat to marine ecosystems, potentially altering species physiology and behavior.
• Acclimation and adaptation mechanisms in wild populations facing elevated pCO2 remain largely unexplored.

Purpose of the Study:

• To investigate molecular responses and adaptive potential of coral reef fish to elevated CO2.
• To compare transcriptional changes across six fish species at a natural CO2 seep.

Main Methods:

• Brain transcriptomic analysis of six coral reef fish species.
• Comparison of gene expression patterns between a volcanic CO2 seep and a control reef.
• Assessment of gene expression reversibility and evolutionary rates.

Main Results:

• Elevated pCO2 induced common molecular responses (circadian rhythm, immune system) with varying magnitudes across species.
• Acanthochromis polyacanthus exhibited high transcriptional plasticity, particularly in genes regulating intracellular pH and neural activity.
• Gene expression changes in A. polyacanthus were reversible post-CO2 reduction.
• A. polyacanthus showed a higher evolutionary rate and positive selection in key functions under elevated CO2.

Conclusions:

• Species-specific molecular toolkits influence the ability to cope with ocean acidification.
• Acanthochromis polyacanthus demonstrates a capacity for acclimation and adaptation to elevated CO2 through enhanced transcriptional plasticity.
• Understanding these molecular mechanisms is crucial for predicting marine species' resilience to future ocean changes.