Multiscale mechanical consequences of ocean acidification for cold-water corals

Area of Science:

• Marine Biology
• Geology
• Materials Science

Background:

• Ocean acidification poses a significant threat to deep-sea corals, jeopardizing the reef framework habitats they construct.
• The structural weakening of coral reefs can lead to ecosystem-scale habitat collapse, diminishing biodiversity support.

Purpose of the Study:

• To investigate the mechanisms behind coral reef crumbling and collapse under increasing ocean acidity and porosity.
• To predict the failure of coral structures using a combination of experimental and computational methods.

Main Methods:

• Utilized electron back-scatter diffraction, micro-computed tomography, and micromechanical experiments.
• Employed molecular dynamics and continuum micromechanics simulations to model coral structure failure.
• Synthesized data from laboratory experiments and computational models.

Main Results:

• Cold-water coral (CWC) skeletons exhibit remarkable mechanical properties, with a compressive strength of 462 MPa and stiffness of 45-67 GPa.
• CWCs retain skeletal material strength even under simulated future oceanic conditions, despite a decrease in stiffness.
• Increased porosity, even from minor dissolution or bioerosion, significantly elevates the risk of coral habitat crumbling.

Conclusions:

• Understanding coral material properties and failure mechanisms under changing ocean chemistry is crucial for conservation.
• Models predict that increased porosity drastically increases the risk of coral habitat crumbling.
• This research aids in identifying vulnerable deep-sea ecosystems and assessing impacts on biodiversity for future management.