Coral Carbonic Anhydrases: Regulation by Ocean Acidification

Area of Science:

• Marine Biology
• Oceanography
• Coral Reef Ecology

Background:

• Global change, including ocean acidification (OA) and warming, poses significant threats to marine ecosystems.
• Ocean acidification alters seawater carbonate chemistry, challenging coral calcification and skeletal integrity.
• Previous research focused on calcification rates, with limited understanding of the underlying physiological mechanisms.

Purpose of the Study:

• To investigate the regulation of carbonic anhydrases (CAs), key enzymes in coral calcification, under ocean acidification scenarios.
• To determine the impact of OA on the enzyme activity and gene expression of two specific carbonic anhydrase isoforms in *Stylophora pistillata*.

Main Methods:

• Enzyme activity assays were conducted to measure the effect of pH on two carbonic anhydrase isoforms.
• Gene expression analysis was performed in vivo to assess the response of these enzymes to OA.
• Experiments considered the combined effects of OA and temperature on enzyme function.

Main Results:

• Both carbonic anhydrase isoforms exhibited changes in gene expression under ocean acidification conditions.
• Ocean acidification and temperature significantly affected the activity of the measured carbonic anhydrase enzymes.
• Temperature increase may potentially counteract the negative effects of ocean acidification on enzyme activity.

Conclusions:

• Ocean acidification directly influences the physiological mechanisms of coral calcification by altering carbonic anhydrase activity and gene expression.
• The interplay between ocean acidification and temperature is critical, with temperature potentially mitigating OA's impact on enzyme function.
• Transcriptomic data on carbonic anhydrases in stress experiments require careful interpretation, considering both gene expression and enzyme activity.