Fig. 1

Map of the Eastern Gulf of Mexico (GoM) showing the 111 sampling locations and bathymetry of the study area. Circle sizes indicate thermospore OTU richness for each location. Color shades of the circles indicate the number of oil-qualified extracts (n = 0, 1, 2, 3) in the sediment core for that location. The semi-transparent dark polygons indicate four different geologic provinces within the sampling area. The inset map shows the location and extent of the study area relative to the area of the entire GoM basin as well as the region affected by the Loop Current, the major ocean current in the GoM. Maps were drawn using ArcGIS Desktop 10.4