Mussel periostracum protects against shell dissolution

Area of Science:

• Marine biology
• Oceanography
• Biomineralization

Background:

• Seawater pH reduction poses a threat to the shell integrity of marine calcifying organisms.
• The periostracum, an external organic layer in molluscs, may offer protection against shell dissolution in corrosive conditions.

Purpose of the Study:

• To test the hypothesis that the periostracum protects mussel shells from dissolution under reduced pH.
• To investigate the influence of periostracum cover and surface texture on shell dissolution rates.
• To assess field-based periostracum cover in different intertidal habitats.

Main Methods:

• Quantified shell dissolution rates of Mytilus californianus across pH levels (7.7, 7.5, 7.4).
• Assessed shell dissolution as a function of periostracum cover and induced surface texture.
• Measured periostracum cover in various intertidal zones.

Main Results:

• Shell dissolution decreased threefold with increased periostracum cover (10% to 85%).
• Lower pH and rougher shell surfaces (post-periostracum removal) led to higher dissolution rates.
• Periostracum loss was greater in higher, sunnier intertidal locations.

Conclusions:

• The periostracum provides significant protection against shell dissolution in mussels.
• Environmental factors like pH and surface texture influence shell vulnerability.
• Marine organisms' protective structures are crucial for adapting to global environmental changes.