The millions of gallons of oil that spilled from the Deepwater Horizon in 2010 may be finding its way out of the ocean and into the bodies of land-dwelling animals, according to a new study by a Cal Poly Pomona biology professor.
The research is potentially groundbreaking because it appears to show for the first time that the oil spill could be affecting creatures that don’t live in the ocean.
“We tend to think of terrestrial ecosystems as safe from oil contamination,” says Andrea Bonisoli Alquati, a Cal Poly Pomona biology professor specializing in environmental toxicology. “However, the boundary between marine and terrestrial ecosystems is much less defined than we assume.”
To find out if that pollution was finding its way onto land through food chains, Bonisoli Alquati and colleagues at Louisiana State University looked at seaside sparrows, a small species of bird that lives in marshes along the Louisiana coast.
The analysis isn’t as simple as looking for oiled birds, however. When crude oil enters a food chain, it doesn’t remain in its original form for long, so researchers cannot look for the presence of the oil itself. Instead, they look at carbon atoms. The carbon in all living organisms is slightly radioactive, but the carbon contained in oil trapped underground is not. As the non-radioactive carbon from crude oil moves through a food chain, it takes the place of the radioactive carbon, leaving its fingerprints on the molecules that make up an organism’s tissues.
When they analyzed the feathers of and the food consumed by the sparrows, they found those fingerprints, suggesting to the researchers that the birds’ food chain has been contaminated by oil.
Though it’s unclear if that’s having an effect on the birds, the researchers note that sparrows living in areas that had been oiled are showing less success at reproducing than their counterparts living in areas Deepwater Horizon oil didn’t reach. Bonisoli Alquati says he intends to investigate in future studies how the contamination could be affecting the birds’ genes, their behavior and their ability to raise offspring.
Bonisoli Alquati is a new addition to Cal Poly Pomona. In addition to his study of Deepwater Horizon’s effects, he has researched how radiation is affecting birds in Chernobyl and Fukushima. Earlier this year, he documented his journeys through Fukushima on Instagram for Smithsonian Magazine.
To read the study in its entirety, click here.