Data from: Evolutionary responses to crude oil from the Deepwater Horizon oil spill by the copepod Eurytemora affinis

The BP Deepwater Horizon Oil Disaster was the most catastrophic offshore
oil spill in U.S. history, yet we still have a poor understanding of how
organisms could evolve in response to the toxic effects of crude oil. This
study offers a rare analysis of how fitness-related traits could evolve
rapidly in response to crude oil toxicity. We examined evolutionary
responses of populations of the common copepod Eurytemora affinis residing
in the Gulf of Mexico, by comparing crude oil tolerance of populations
collected before versus after the Deepwater Horizon oil spill of 2010. In
addition, we imposed laboratory selection for crude oil tolerance for ~8
generations, using an E. affinis population collected from before the oil
spill. We found evolutionary increases in crude oil tolerance in the wild
population following the oil spill, relative to the population collected
before the oil spill. The post-oil spill population showed increased
survival and rapid development time in the presence of crude oil. In
contrast, evolutionary responses following laboratory selection were less
clear; though, development time from metamorphosis to adult in the
presence of crude oil did become more rapid after selection. We did find
that the wild population, used in both experiments, harbored significant
genetic variation in crude oil tolerance, upon which selection could act.
Thus, our study indicated that crude oil tolerance could evolve, but
perhaps not on the relatively short time scale of the laboratory selection
experiment. This study contributes novel insights into evolutionary
responses to crude oil, in directly examining fitness-related traits
before and after an oil spill, and in observing evolutionary responses
following laboratory selection.