Picocystis

Picocystis is a monotypic genus of green algae, the sole species is Picocystis salinarum.^[1] It is placed within its own class, Picocystophyceae in the division Chlorophyta.^[2]

Picocystis
Picocystis salinarum
Scientific classification
Kingdom:	Plantae
Division:	Chlorophyta
Class:	Picocystophyceae Eikrem & Lopes dos Santos
Order:	Picocystales Eikrem & Lopes dos Santos
Family:	Picocystaceae Eikrem & Lopes dos Santos
Genus:	Picocystis R.A.Lewin 2001 emend. Eikrem & Lopes dos Santos 2017
Species:	P. salinarum
Binomial name
Picocystis salinarum R.A.Lewin 2001

Structure

Picocystis salinarum cells under normal conditions have a spherical or oval shape. Their size ranges from 2 to 3 μm 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 alga.

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]

Habitat

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).