Final answer:
A single coccolithophore is surrounded by multiple plates of calcium carbonate known as coccoliths, playing a significant role in oxygen production and carbon sequestration.
Step-by-step explanation:
At any one time, a single coccolithophore is attached to or surrounded by at least multiple plates of calcium carbonate. These plates, known as coccoliths, are essential in identifying these unicellular marine algae and contribute significantly to the earth's geology and ecology.
Coccolithophores, belonging to the kingdom Protista, are important photosynthetic organisms in open oceans, contributing to oxygen production and acting as a carbon sink by forming coccoliths from dissolved carbonate ions, which are derived from carbon dioxide. When coccolithophores die, their coccoliths may dissolve back into the solution or sink to the ocean floor to form deposits, such as the famous White Cliffs of Dover.