Halobacteria also possess a second pigment, halorhodopsin, which pumps in chloride ions in response to photons, creating a voltage gradient and assisting in the production of energy from light.

[2] Studies show Halobacteriales can also be found in environments where sulfur reduction takes part as well as in salinity salterns, seawater black smoker, coastal salt marshes and chimney structures.

[4] The wide variety of biochemical characteristics and different ecological niches of the class Haloarchaea proved to be an unreliable tool in clarifying the evolutionary relationships of Halobacteria above the genus level.

[4] In 2015, Gupta et al. proposed the division of class Halobacteria into three orders, Halobacteriales, Haloferacales and Natrialbales based on comparative genomic analyses and the branching pattern of various phylogenetic trees constructed from several different datasets of conserved proteins and 16S rRNA sequences.

[8] Natronoarchaeaceae Haloparvum ** Halopenitus ** Halorubrum {Halorubraceae} Haloferacaceae Halobacteriaceae Haloarculaceae Halostella * {"Halostellaceae"} Halalkalicoccus {"Halalkalicoccaceae"} Halococcus {Halococcaceae} Salinarchaeum * {"Salinarchaeaceae"} Haladaptaceae (incl.