Data from: Thermal evolution offsets the elevated toxicity of a contaminant under warming: a resurrection study in Daphnia magna

Synergistic interactions between temperature and contaminants are a major
challenge for ecological risk assessment, especially under global warming.
While thermal evolution may increase the ability to deal with warming, it
is unknown whether it may also affect the ability to deal with the many
contaminants that are more toxic at higher temperatures. We investigated
how evolution of genetic adaptation to warming affected the interactions
between warming and a novel stressor: zinc oxide nanoparticles (nZnO) in a
natural population of Daphnia magna using resurrection ecology. We hatched
resting eggs from two D. magna subpopulations (old: 1955-1965, recent:
1995-2005) from the sediment of a lake that experienced an increase in
average temperature and in recurrence of heat waves but was never exposed
to industrial waste. In the old ‘ancestral’ subpopulation, exposure to a
sublethal concentration of nZnO decreased the intrinsic growth rate,
metabolic activity and energy reserves at 24°C but not at 20°C, indicating
a synergism between warming and nZnO. In contrast, these synergistic
effects disappeared in the recent ‘derived’ subpopulation that evolved a
lower sensitivity to nZnO at 24°C, which indicates that thermal evolution
could offset the elevated toxicity of nZnO under warming. This evolution
of reduced sensitivity to nZnO under warming could not be explained by
changes in the total internal zinc accumulation but was partially
associated with the evolution of the expression of a key metal
detoxification gene under warming. Our results suggest that the increased
sensitivity to the sublethal concentration of nZnO under the predicted 4°C
warming by the end of this century may be counteracted by thermal
evolution in this D. magna population. Our results illustrate the
importance of evolution to warming in shaping the responses to another
anthropogenic stressor, here a contaminant. More general, genetic
adaptation to an environmental stressor may ensure that synergistic
effects between contaminants and this environmental stressor will not be
present anymore.