Eurythermal

Eurythermal describes organisms that can tolerate or thrive across a broad range of environmental temperatures. The term derives from the Greek eurys "wide" and thermos "heat." In biology, it is used to characterize thermal breadth independent of other factors such as humidity or pH.

This contrasts with stenothermal organisms, which survive only within a narrow temperature window. Eurythermy is a form of thermal plasticity that enables populations to cope with fluctuating environments, including diurnal temperature variation, seasonal change, and habitats with abrupt thermal shifts.

Eurythermy occurs across many domains of life. Bacteria and fungi commonly show broad thermal tolerance, as do some algae, plants, invertebrates, and aquatic vertebrates in variable habitats such as intertidal zones, deserts, and alpine streams.

Adaptations underlying eurythermy include adjustments in membrane lipid composition to maintain fluidity, the synthesis of heat shock proteins and other chaperones, expression of enzymes with broad temperature optima, and accumulation of compatible solutes that stabilize cellular structures.

Understanding eurythermy informs ecology and biogeography, helps explain species resilience to climate variability, and can guide applications in biotechnology and bioremediation where organisms must function across broad temperatures.