= Halophile
A <halophile> is an <organism> adapted to growth in high-salt environments, with its preferred or required salt conditions depending on the <species>. The term describes a way of living, rather than one <clade>. For example, <Haloferax volcanii> is a member of <Archaea>, whereas <Dunaliella parva> belongs to the <algae>. A <halophile> must sustain cellular function despite the effects of external <salinity> on <water> movement and <proteins>.<The Complete Genome Sequence of Haloferax volcanii DS2, a Model Archaeon by Amber L. Hartman and others>[Introduction: halophilic model organism]{ref}
A concrete mechanism was tested by <Ami Ben-Amotz> and <Mordhay Avron> in 1973. They measured intracellular <glycerol> in <Dunaliella parva> and estimated its concentration using cellular volume. Changing external <sodium chloride> caused corresponding changes in intracellular <glycerol>, with a new balance through <osmoregulation> reached after about 90 minutes. Their leakage measurements supported metabolic production and breakdown of <glycerol> as the explanation, rather than simple escape of the solute. This connects environmental change to measurable <osmoregulation>.<The Role of Glycerol in the Osmotic Regulation of the Halophilic Alga Dunaliella parva by Ami Ben-Amotz and Mordhay Avron>[Abstract; salt-shift and leakage observations]{ref}
The experiment illustrates why a growth habitat alone does not identify a mechanism. Two <halophiles> can inhabit salty surroundings while controlling intracellular solutes differently. A useful comparison specifies the <organism>, external salt concentration, cellular response and time after the salt change.
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