Interindividual plasticity in metabolic and thermal tolerance traits from populations subjected to recent anthropogenic heating

To better understand temperature’s role in the interaction between local evolutionary adaptation and physiological plasticity, we investigated acclimation effects on metabolic performance and thermal tolerance among natural Fundulus heteroclitus populations from different thermal environments. F. heteroclitus populations experience large daily and seasonal temperature variations, as well as local mean temperature differences across their large geographic cline. In this study, we focus on three populations: one locally heated (32°C) by thermal effluence (TE) from the Oyster Creek Nuclear Generating Station, NJ and two nearby reference populations that do not experience local heating (28°C). After acclimation to 12°C or 28°C, we quantified whole animal metabolic rate (WAM), critical thermal maximum (CTMax) and substrate specific cardiac metabolic rate (CaM, substrates: glucose, fatty acids, lactate plus ketones plus ethanol, and endogenous [i.e., no added substrates]) in ~160 individuals ...