Oil Spill Affects Gene Expression Profiles in Exposed Dolphins

The Deepwater Horizon oil spill in the Northern Gulf of Mexico triggered gene expression changes in bottlenose dolphins exposed to the environmental disaster, a genetic study published this week in PLOS One reveals. The findings may lead to the development of new molecular biomarkers in these and related animals. Following the explosion of the Deepwater Horizon oil drilling platform and subsequent release of millions of barrels of oil into the Gulf in early 2010, wildlife researchers identified — primarily through hands-on evaluations and standard diagnostic panels — a range of conditions in exposed dolphins including lung disease, inflammation, impaired stress responses, and reproductive failure. Aiming to leverage new technologies for such assessments, a team led by scientists from the National Marine Mammal Foundation examined transcriptomic profiles in blood samples taken from 76 dolphins in waters near Barataria Bay, Louisiana, and Sarasota Bay, Florida, between 2013 and 2018. For the Barataria Bay dolphins, the investigators find evidence of a shift in immune response, cytoskeletal alterations, and mitochondrial dysfunction in animals that were likely exposed to Deepwater Horizon oiling. While gene expression profiles between the two dolphin groups were altered in all years, profiles from 2013 exhibited the greatest gene expression changes. Differentially expressed transcripts included genes involved in immunity, inflammation, reproduction failure, and cardiac dysfunction. The study's results, the authors write, may help in the development of biomarkers "that can provide critical health information to wildlife veterinarians, researchers, managers, and other stakeholders, even in the absence of full veterinary assessments.