Foraminifera of petroleum platforms, Louisiana shelf, Gulf of Mexico

► We sampled the biofouled crust of five Louisiana-shelf petroleum platforms. ► About 38% of the foraminiferal species were obligate or facultative sessile. ► The provenances of many sessile species are patches of hardground to the west. ► Their settlement on platforms is facilitated by a variable coastal current. ► As habitat islands, offshore petroleum platforms affect foraminiferal biogeography.