Red coral extinction risk enhanced by ocean acidification

Area of Science:

• Marine Biology
• Oceanography
• Ecology

Background:

• Red coral (Corallium rubrum) is a key habitat-forming species in mesophotic ecosystems, supporting biodiversity.
• This precious coral faces threats from over-exploitation and climate change-induced mass mortality events.

Purpose of the Study:

• To investigate the impact of projected ocean acidification on the physiological processes of Corallium rubrum.
• To assess the long-term risks to Corallium rubrum populations and mesophotic habitats.

Main Methods:

• Experimental manipulation of pCO2 levels to simulate end-of-century ocean acidification scenarios.
• Measurement of biocalcification rates, growth, and polyp feeding activity in Corallium rubrum.

Main Results:

• Significant reductions in biocalcification, growth rates, and polyp feeding activity were observed under elevated pCO2.
• A 0.2 pH decrease, simulating future ocean acidification, severely impacted coral physiology.

Conclusions:

• Ocean acidification poses a significant extinction risk to long-lived Corallium rubrum populations.
• The decline of this habitat-forming species may lead to cascading negative effects on mesophotic zone functioning globally.