Knowra Bivalve shell Bivalve shell A bivalve shell consists of two calcareous valves joined by a hinge and secreted by the mantle. Its layers protect the animal and can grow as the animal grows.
Molluscan mantle : A tissue layer in molluscs that secretes shell material and often forms a mantle cavity. The mantle’s edge secretes and shapes the growing margins of both valves.
Shell accretion : The addition of new shell material at a shell’s growing edge or surface. Bivalve shells enlarge as the mantle adds material along their margins.
Sclerochronology : The study of growth patterns in hard biological structures to reconstruct environmental and life history. Growth increments in shells can record seasonal conditions and animal age.
Shell-boring organisms : Organisms that excavate or penetrate hard shells, often for shelter, feeding, or attachment. Boring sponges and other organisms exploit shells as habitat or food-bearing surfaces.
Calcium carbonate : A chemical compound, CaCO₃, found in minerals such as calcite and aragonite. This compound forms the mineral component of most bivalve shells.
Biomineralization : The process by which living organisms produce minerals through biological control. Bivalves regulate the deposition of calcium carbonate and organic matrix.
Stable isotope analysis : The measurement of isotope ratios to investigate biological, geological, or environmental processes. Shell isotope ratios can preserve clues about water temperature and chemistry.
Predation on bivalves : The capture and consumption of bivalves by animals such as crabs, fishes, and snails. Shell thickness, shape, and strength influence vulnerability to predators.
Nacre : A lustrous composite material made of microscopic aragonite tablets and organic layers. In some bivalves, this inner shell layer helps resist fracture.
Adductor muscle : A muscle that brings the two valves of a bivalve together. Its contraction closes the shell against the outward pull of the hinge ligament.
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