These organisms usually have thick cell walls that prevent dehydration and generally divide slowly. Salt concentrations that are higher outside the cell than inside cause water to leave cells. The cytoplasmic membrane pulls inward, away from the cell wall. If enough water leaves the cell, plasmolysis kills the cell. High salt solutions can kill most bacteria by plasmolysis.
Halophiles are bacteria that are adapted to live in high salt environments.
They contain very high internal salt concentrations, and sometimes pump water back inside. Some microbes only thrive under conditions of extreme temperature, pressure, pH, dryness, or osmotic strength. These amazing microbes are often archeobacteria. Some extremophils have been isolated and used as a source of industrially useful enzymes that are resistant to extreme conditions.