Thicker Shells Compensate Extensive Dissolution in Brachiopods under Future Ocean Acidification.

Area of Science:

• Marine Biology
• Climate Change Science
• Oceanography

Background:

• Organisms with long generation times rely on phenotypic plasticity for survival amidst environmental shifts.
• Marine calcifiers, such as brachiopods, are highly susceptible to ocean acidification due to shell dissolution and reduced carbonate ions.
• Long-term experiments are crucial for understanding acclimatization and adaptation in marine species under changing environmental conditions.

Purpose of the Study:

• To investigate the response of polar and temperate brachiopods to predicted ocean acidification and warming.
• To assess the capacity for phenotypic plasticity in marine calcifiers under long-term stress.
• To identify compensatory mechanisms against shell dissolution in brachiopods.

Main Methods:

• Long-term laboratory culture of polar (Liothyrella uva) and temperate (Calloria inconspicua) brachiopods.
• Exposure to predicted end-century acidification (decreasing pH) and warming conditions.
• Analysis of shell dissolution and thickness, including outer primary and inner secondary layer changes.

Main Results:

• Both brachiopod species experienced significant shell dissolution, more pronounced in the polar species (Liothylla uva).
• The polar brachiopod exhibited a compensatory response by increasing inner secondary layer thickness, resulting in a thicker overall shell.
• The temperate brachiopod (Calloria inconspicua) showed less dissolution and no significant change in shell thickness.
• Elevated temperatures did not influence shell dissolution or thickness in either species.

Conclusions:

• Brachiopod calcification demonstrates significant plasticity, enabling shell thickening as a response to extensive dissolution.
• This compensatory mechanism suggests a potential pathway for marine calcifiers to cope with future ocean acidification.
• The findings offer insights into the resilience of marine calcifiers and their ability to adapt to climate change impacts.