Biomineralization in coccolithophores.

Unicellular marine algae known as coccolithophores are potentially important organisms for the study of gravitational effects on biomineralization. The cells are easily cultured under low maintenance conditions and produce intricately sculpted calcite scales known as coccoliths in specialized Golgi-derived vesicles. Many mutants are available with different types of mineral defects ranging from the complete absence of mineral to the presence of mineral with orientational, morphological, number, and size defects. This short review summarizes what is currently known about the three phases of coccolith mineralization--mineral ion transport, mineral nucleation, and crystal growth--in Pleurochrysis carterae and Emiliania huxleyi in the earth's normal gravitational field.