Lake water chemistry and local adaptation shape NaCl toxicity in .

The increasing application of road deicing agents (e.g., NaCl) has caused widespread salinization of freshwater environments.

Lake water chemistry and population of origin interact to shape fecundity and growth in .

Freshwater environments vary widely in ion availability, owing to both natural and anthropogenic drivers. Field and laboratory work point to the importance of overall salinity, as well as cation depletion, in shaping the physiology, behavior, and ecology of freshwater taxa. Yet, we currently have a poor understanding of the degree to which populations may vary in response to ion availability.