Polarella inhabits channels within ice formations in both the Arctic and Antarctic polar regions,[3] where it plays an important role as a primary producer.

[4] Polarella is a thecate dinoflagellate, wherein the cell has an outer covering of cellulose plates, which are arranged in nine latitudinal series.

and Polarella has a zygotic life history,[5] wherein it alternates between a motile vegetative phase and a non-motile spiny cyst.

[1] The genus Polarella was first described by Marina Montresor, Gabriele Procaccini, and Diane K. Stoecker as published in the Journal of Phycology in 1999.

[1][3] Initially, the type specimen of P. glacialis was sampled from the McMurdo Sound area of the Ross Sea in Antarctica.

[7] Polarella is photoautotrophic, has been found to greatly contribute to the biomass and primary production within the sea-ice brine channels it inhabits,[4] and is present at particularly high densities as it blooms in the austral spring (September to November).

The cingulum is deep and wraps around the mid region of the cell, and the sulcus is a shallower indentation, present only through the hypotheca.

An interesting aspect present within the cytoplasm, at the edge of the cell on the ventral side is the refractive body, a structure consisting of four or five vesicles containing crystalline pressed close together.

It has been found by Stephens et al. (2020) that 68% of the genome of Polarella is composed of sequences that are repetitive, specifically with long terminal repeats, which contributes to divergence between species7.

The spikes arise from the outer most layer of the wall surrounding the cyst, and form in the center of polygonal plates.

As a dinoflagellate, Polarella can undergo both asexual and sexual reproduction, and has a zygotic life history as described by Spector (1984).

These closely related genera can be distinguished by the contrasts between their life histories and distributions as discussed by Montresor et al.

[1] Species of Symbiodinium have a life history stage that is coccoid and is an endosymbiont of various invertebrates, and is distributed throughout the oceans in the tropical and subtropical regions.

Furthermore, the theca of Symbiodinium species is arranged in series of seven latitudinal plates during its flagellated, motile life stage.

[6] The fossil history applicable to Polarella is in relation to its ability to form cysts as discussed by Palliani and Riding (2003).