The acute transcriptomic response of coral-algae interactions to pH fluctuation

Area of Science:

• Marine Biology
• Coral Reef Ecology
• Symbiosis Research

Background:

• Coral-algal symbiosis is vital for reef survival.
• Understanding host-endosymbiont responses to environmental shifts is crucial.
• Extreme climate events pose significant threats to coral reefs.

Purpose of the Study:

• Investigate coral and endosymbiont transcriptomic changes under abrupt pH shifts.
• Determine the impact of high-CO2 exposure on symbiotic interactions.
• Elucidate the physiological costs of coral adaptation to environmental variability.

Main Methods:

• Transcriptomic analysis of coral and endosymbiont.
• Exposure of corals to two distinct pH levels (7.60 and 8.35).
• Analysis of gene expression related to carbon acquisition, fixation, and calcification.

Main Results:

• Endosymbionts showed downregulated carbon acquisition and fixation, suggesting photosynthetic dysfunction.
• Corals maintained calcification but experienced negative effects on energy dynamics.
• Evidence of increased energy expenditure for metabolic adaptation, including DNA repair and homeostasis.

Conclusions:

• High-CO2 conditions compromise the coral-algal mutualistic relationship.
• Corals face significant energetic costs to adapt to low pH environments.
• This study enhances understanding of coral symbiosis under future climate change scenarios.