Long-term acclimation and potential scope for thermal resilience in Southern Ocean bivalves

Different physiological thresholds of species across biogeographic boundaries can show a long-term scope for adaptation. Characterised by cold-stenothermal conditions, polar and deep-sea environments are constrained by thermal stability across wide regions, and polar invertebrates are broadly considered to be highly sensitive to only subtle changes in thermal regime. We examine the respiratory response of two distinct biogeographic populations of the widespread bivalve Lissarca notorcadensis from deep waters in the Southern Ocean to acute thermal changes, and present distinct respiratory responses for each population. Populations from the Weddell Sea living in cooler water temperatures (