Temperature-dependent metabolism in Antarctic fish: Do habitat temperature conditions affect thermal tolerance ranges?

摘要

Climatic warming is most pronounced in theudpolar regions. For marine ectotherms such as fish, temperatureudis a key abiotic factor, influencing metabolicudprocesses. Species distribution and abundance are drivenudby reproduction and growth, which depend on availableudenergy exceeding baseline maintenance costs. These routineudmetabolic costs make up a large part of the energyudexpenditure. Thermal stress can increase routine metabolism,udaffecting an organism’s fitness. Data of routineudmetabolic rates of Antarctic fish are scarce, and comparabilityudof existing data sets is often problematic due toudecological differences between species and in experimentaludprotocols. Our objective was to compare routine metabolismudand thermal sensitivity of species with similar ecotypesudbut different thermal environments to assess possibleudecological implications of warming waters on energyudexpenditure in Antarctic fish, a fauna characterised byudgeographic isolation, endemism and putative thermaludadaptation. We measured routine metabolic rates of threeudbenthic Antarctic fish species from low- and high-Antarctic udregions at habitat temperature and during acute temperatureudincrease. Our analysis revealed differences in metabolicudrates at the same temperature suggesting local adaptation toudhabitat temperature. Acute thermal stress induced a comparableudresponse of metabolic rates to increasing temperature.udWe conclude that higher metabolic rates and thusudhigher energetic costs could be associated with narrowerudthermal windows, a potential disadvantage to the endemicudhigh-Antarctic fish fauna facing the challenge of climateudchange.