The Deepwater Horizon oil spill inhibited microorganisms' nitrogen cycle, which is critical to ecosystem development and decomposition, according to research by Florida Gulf Coast University.
While some bacteria served as "glorious brave fighters" to help clean up the spill by breaking down the oil, other groups of microorganisms such as archaea were victims, Hidetoshi Urakawa, the lead researcher and assistant professor of the university's department of marine and ecological sciences, said by email.
"The important finding of our study was that oil spills not only damage marine animals and entire food webs, but also the nitrogen cycle, which is one of the major bloodstreams of our planet," Urakawa said.
The data, published in February in the journal Environmental Pollution, found that one common archae bacterium called Nitrosopumilus maritimus showed a particularly high sensitivity to crude oil.
That susceptibility may have an ecological significance, even leading to a shift to bacterial dominance in the aftermath of a major oil spill, the researchers said. But they also cautioned that the variation in petroleum toxicity might be explained in part by the different sizes of microorganisms.
Urakawa said it also might be possible to take the most sensitive archaea and develop a bioassay to measure and monitor petroleum toxicity in the seawater and "help map a future spill."
To conduct their study, the researchers collected tar balls that had drifted ashore in nearby Panama City, Florida, and tested the toxicity responses of bacteria and archaea to oil contamination.
The Deepwater Horizon oil spill provided an opportunity to "think about some of the unseen damages of nature" in the deep ocean, Urakawa said. Jose Barreto, professor of Florida Gulf Coast University's department of chemistry and mathematics, collaborated on the project.
—Jeff Smith