Experts argue for further in-depth assessments of the impacts of dispersants on microorganisms to guide their use in response to future oil spills. Chemical dispersants are widely used in emergency responses to oil spills in marine environments as a means of stimulating microbial degradation of oil. After the Deepwater Horizon spill in 2010, dispersants were applied to the sea surface and deep waters of the Gulf of Mexico, the latter of which was unprecedented. Dispersants were used as a first line of defense even though little is known about how they affect microbial communities or the biodegradation activities they are intended to spur....