Integrated organismal responses induced by ecologically-relevant pCO2 and temperature exposures in developing lake sturgeon

Atmospheric CO2 and 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 of p CO2 in freshwater systems. Lake sturgeon ( Acipenser fulvescens ) groups were raised in current and projected levels of warming and p CO2. Following an overwintering period, lake sturgeon were exposed to a transient increase in p CO2, 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 CO2 exposure. These results demonstrate compensatory and compounding mechanisms of p CO2 and warming dependent on developmental conditions of a freshwater fish, and provide key information for responses to future climate change. ### Competing Interest Statement The authors have declared no competing interest.