coccolith
/ˈkɒkəlɪθ
/noun Biology
A minute rounded calcareous platelet, numbers of which form the spherical shells of coccolithophores.At this rate it is possible to produce an average 100 metre thickness of coccoliths as calcareous ooze on the ocean floor in less than 200 years....
- Chalk, though it may include shell fragments, is predominantly composed of coccoliths from planktonic algae, forming fine-grained limestone.
- The living cell possesses a gelatinous sheath in which are embedded calcareous plates termed coccoliths.
Origin
Mid 19th century: from Greek kokkos 'grain or berry' + lithos 'stone'.