Osmophile

an organism capable of living in a substrate with a high osmotic pressure.

An organism’s compatibility with a certain habitat depends not so much on osmotic pressure as on the chemical properties of the medium. True osmophiles—organisms that grow equally well in isoosmotic solutions of different compositions—do not exist. Organisms are classified according to the dominant ion in their substrate and according to their need for that ion; thus, for instance, they can be calcephilic, magnophilic, fluorophilic, selenophilic, natrophilic, or kaliophilic. In such cases the osmotic pressure is derived from the chemical composition of the medium. Replacement of the substrate or change in its ionic composition usually results in death of the organism.