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.

BP深水地平线漏油事件为美国历史上最严重的近海石油泄漏灾难，然而当前学界对生物体如何响应原油毒性产生适应性进化的机制仍知之甚少。本研究针对适合度相关性状如何快速响应原油毒性发生进化这一问题，开展了少见的针对性分析。
我们以栖息于墨西哥湾的常见桡足类（copepod）近亲真宽水蚤（Eurytemora affinis）种群为研究对象，通过对比2010年深水地平线漏油事件发生前后采集的种群的原油耐受性，探究其野外环境中的进化响应。此外，我们利用漏油事件前采集的该种群，开展了约8代的原油耐受性实验室选择实验。
研究结果显示：相较于漏油事件前采集的种群，漏油后野外种群的原油耐受性出现了进化提升。漏油后种群在原油暴露环境下存活率更高、发育速度更快。与之形成对照的是，实验室选择实验后的进化响应不甚明确；不过，在原油暴露条件下，从变态发育至成虫的发育时长在选择实验后确实有所缩短。我们同时发现，本研究两项实验共用的野外种群，其原油耐受性存在显著的遗传变异，可作为选择作用的靶点。因此，本研究表明原油耐受性可发生进化，但或许无法在实验室选择实验的较短时间尺度内完成。
本研究通过直接对比漏油事件前后的适合度相关性状，并观测实验室选择后的进化响应，为原油毒性的进化响应研究提供了全新的学术见解。