Barotolerance

Barotolerance refers to the ability of an organism or biological system to endure changes in ambient hydrostatic pressure without sustaining irreversible damage or loss of function. The concept is used across microbiology, marine biology, physiology, and engineering to describe how life forms and tissues respond to pressure shifts encountered in environments ranging from shallow waters to the deep sea.

Organisms are categorized by their pressure preferences. Barotolerant species can survive across a broad pressure range, including elevated pressures, but do not require high pressure for growth. Barophilic or piezophilic organisms show a preference for high pressure and may grow poorly at atmospheric pressure. Barosensitive organisms are harmed by increased pressure. These terms help describe distributions in marine ecosystems and responses to pressure changes such as during ascent in diving or decompression.

Mechanisms of barotolerance include cellular and molecular adaptations that preserve membrane integrity and enzyme activity under pressure. Changes in membrane lipid composition to maintain fluidity, upregulation of molecular chaperones and DNA repair systems, and adjustments in cytoskeletal structure help maintain function. Metabolic shifts and accumulation of compatible solutes can also contribute to tolerance.

Applications and examples include studying deep-sea microbiota, evaluating food preservation and sterilization where pressure is a factor, and understanding human divers' risks such as barotrauma. Researchers assess barotolerance using high-pressure culture systems and pressure survival assays to compare strains and species across pressure ranges.