One year after the notorious BP Deepwater Horizon oil spill in the Gulf of Mexico and two decades after the Exxon Valdez spill in Prince William Sound off the coast of Alaska the scientific lesson is clear – microbes matter! Despite vast differences in the impacted marine ecosystems and the circumstances of these two worst oil spills in U.S. history, oil-degrading microorganisms played a significant role in reducing the overall environmental impact of both spills.