The members of the class Cyanidiophyceae are among the most acidophilic known photosynthetic organisms, and the growth conditions of G. sulphuraria – pH between 0 and 4, and temperatures up to 56 °C – are among the most extreme known for eukaryotes.

Analysis of its genome suggests that its thermoacidophilic adaptations derive from horizontal gene transfer from archaea and bacteria, another rarity among eukaryotes.

The earliest description of an organism corresponding to the modern G. sulphuraria was published in 1899 by an Italian scientist, A. Galdieri, who gave it the name Pleurococcus sulphurarius.

[5] G. sulphuraria is noted for its extreme metabolic flexibility: it is capable of photosynthesis and can also grow heterotrophically on a wide variety of carbon sources, including diverse carbohydrates.

[9] The G. sulphuraria genome contains evidence of extensive horizontal gene transfer (HGT) from thermoacidophilic archaea and bacteria, explaining the origin of its adaptation to this environment.

[17] By comparison to Cyanidioschyzon merolae – a unicellular thermoacidophilic red alga that is obligately photoautotrophic – the G. sulphuraria genome contains a large number of genes associated with carbohydrate metabolism and cross-membrane transport.