Integrated organismal responses induced by ecologically-relevantpCO₂and temperature exposures in developing lake sturgeon

Abstract

Atmospheric CO2and temperature are rising concurrently, and may have profound impacts on the transcriptional, physiological, and behavioral responses of aquatic organisms. Further, spring snow melt may cause transient increases ofpCO2in freshwater systems. Lake sturgeon (Acipenser fulvescens) groups were raised in current and projected levels of warming andpCO2. Following an overwintering period, lake sturgeon were exposed to a transient increase inpCO2, simulating a spring melt. Diverging transcriptional patterns were found in each group and metabolic rate was lower in the combined stressor group compared to others. Behavioral assays revealed no effect of environment on alarm cue responses or boldness, but there was a decrease in total activity following an acute CO2exposure. These results demonstrate compensatory and compounding mechanisms ofpCO2and warming dependent on developmental conditions of a freshwater fish, and provide key information for responses to future climate change.