Tar-filled shells and tar balls on the Alabama Gulf coast host distinctive bacterial communities

Tar balls have been persisting along the Gulf coast. Previous research has shown that tar balls from the Gulf coast may contain the human pathogen Vibrio vulnificus. These oil residuals are also commonly found beneath sea shells (hereby called “tar shells”). No research, however, has explored the bacterial communities in tar shells. In this study, tar shell, tar ball, and sand samples on the Alabama Gulf coast at intertidal and supratidal zones were collected and their bacterial communities were assessed using PCR-DGGE and DNA sequencing. Our data suggest that Desulfovibrio and Actinobacteria spp. are dominant in tar shells at intertidal and supratidal zones, but not in tar balls at supratidal zone, while Pseudoalteromonas spp. are dominant in both tar balls and tar shells. This research provides preliminary data for future studies to assess the impacts of tar balls and tar shells on coastal environments and human health.