Picocystis is a monotypic genusofgreen algae, the sole species is Picocystis salinarum.[1] It is placed within its own class, Picocystophyceae in the division Chlorophyta.[2]
Picocystis salinarum cells under normal conditions have a spherical or oval shape. Their size ranges from 2 to 3μm (micrometer, 10^-6) in diameter. Under conditions of nutrient depletion they appear to form a trillobe shape. This trillobe shape gives it the nickname Mickey Mouse, due to its appearance to the famous character's head. The general appearance resembles that of a standard green algae.
The pigments are composed mainly from chlorophyll a and b and the carotenoids violaxanthin, alloxanthin, monadoxanthin, neoxanthin, lutein, diatoxanthin and zeaxanthin.[3][4]
The cell wall is mainly composed of polymers of the monosaccharide arabinose, polyarabinose.[3]
The species have been found in saline or hypersaline alkaline environments.[5][6]
Picocystis is one of the smallest green algae. Picocystis salinarum occurs in vast numbers in Mono Lake, where it is also referred to as Mickey Mouse (see bottom left).
