Deepwater Horizon oil spill's dramatic effect on stingrays' sensory abilities

It has been almost a decade since the Deepwater Horizon Oil spill. Described as the worst environmental disaster in the United States, nearly 5 million barrels of crude oil oozed into the Gulf of Mexico, severely degrading the marine ecosystem immediately surrounding the spill site and directly impacting coastal habitats along 1,773 kilometers of shoreline. About 10 million gallons remain in the sediment at the bottom of the Gulf and may continue to cause severe physiological damages to marine life, including impairment of sensory systems.

Marine fishes rely on the effective functioning of their sensory systems to survive. Despite the obvious importance of their olfactory (sense of smell) system, the impact of crude oil exposure on sensory function remains largely unexplored.

Researchers at Florida Atlantic University are the first to quantify the physiological effects of whole crude oil on the olfactory function of a marine vertebrate—the Atlantic stingray, Hypanus sabinus, an elasmobranch fish. Results of the study, published in Scientific Reports, confirm that exposure to crude oil, at concentrations mimicking those measured in coastal areas following the Deepwater Horizon oil spill, significantly impaired olfactory function in the Atlantic stingray after just 48 hours of exposure. These findings suggest that exposure to crude oil could detrimentally impact fitness, lead to premature death, and cause additional cascading effects through lower trophic levels.

"Elasmobranchs are renowned for their well-developed sensory systems, which are critical to alert them of the presence of predators, prey, mates, and unfavorable environmental conditions. Any impairment of these sensory systems could have a damaging effect on their survival and fitness," said Stephen M. Kajiura, Ph.D., co- author, a professor of biological sciences in FAU's Charles E. Schmidt College of Science and director of the Elasmobranch Research Laboratory at FAU.

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