A report released by the Georgia Sea Grant and the University of Georgia concludes that as much as 79 percent of the oil released into the Gulf of Mexico from the Deepwater Horizon well has not been recovered and remains a threat to the ecosystem.
The conclusion conflicts with a recent report from the government saying that about 75 percent of the oil was gone.
"One major misconception is that oil that has dissolved into water is gone and, therefore, harmless," said Charles Hopkinson, director of Georgia Sea Grant and professor of marine sciences in the University of Georgia Franklin College of Arts and Sciences. "The oil is still out there and it will likely take years to completely degrade. We are still far from a complete understanding of what its impacts are."
Co-authors on the paper include Jay Brandes, associate professor at Skidaway Institute of Oceanography; Samantha Joye, professor of marine sciences at Georgia; Richard Lee, professor emeritus at Skidaway; and Ming-yi Sun, professor of marine sciences at Georgia.
The group analyzed data from the Aug. 2 National Incident Command Report, which calculated an "oil budget" that was widely interpreted to suggest that only 25 percent of the oil from the spill remained.
Hopkinson notes that the reports arrive at different conclusions largely because the Sea Grant and Georgia scientists estimate that the vast majority of the oil classified as dispersed, dissolved or residual is still present, whereas the government's report has been interpreted to suggest that only the "residual" form of oil is still present.
Another difference is that the government's report estimates that 4.9 million barrels of oil were released from the wellhead, while the Sea Grant report uses a figure of 4.1 million barrels because 0.8 million barrels were piped directly from the well to surface ships and did not enter Gulf waters.
On a positive note, the group says natural processes continue to transform, dilute, degrade and evaporate the oil. They add that a circular current known as the Franklin Eddy is preventing the Loop Current from bringing oil-contaminated water from the Gulf to the Atlantic, which bodes well for the East Coast.