METHODS
Test organisms
Organisms were obtained from 2 sources, the University of Southern Mississippi Gulf Coast Research Lab and the University of Maryland Center for Environmental Science. The source laboratories held their own adult brood stock and provided early lifestage Z3/Z4 zoea for testing. Before use in bioassays, zoea were held overnight (25 8C, 28–30 ppt salinity) and fed rotifers obtained from the same in-house culture as the laboratory that provided the zoea.
Test solutions
Two field-collected oil samples were used in these experi- ments. Slick A is a surface slick oil collected on 29 July 2010 from the hold of barge number CTC02404, which was receiving surface slick oil from various skimmer vessels near the Macondo Well. Slick B is a more weathered surface slick oil collected closer to shore on 19 July 2010 by the skimmer vessel