What scientists know about how oil spills can affect the environment – and for how long – is drawn from a range of past events, no two of which have been alike. It means that “the leading scientists can build a model for what they think is going to happen, but we may wake up the next morning and not know exactly what to expect,” says Fischer.
Comparisons with the Exxon Valdez spill, for example, can be misleading because of significant differences in the type of oil, the ecosystems affected, and the way natural processes break down oil.
Moreover, the uncertainty is greater in the current spill. For the most part, researchers have studied the aftermath of surface spills. The Deepwater Horizon blowout occurred at 5,000 feet, dispensing crude oil from seafloor to surface.
Many of the long-term effects may remain hidden as natural processes and chemical dispersants break up the oil into small globules dense enough to sink to the bottom. There, it has the potential to affect bottom dwellers for decades.
Dr. McDowell was a coauthor of a 2003 National Academy of Sciences report that remains a seminal work for understanding the behavior of petroleum and petroleum products spilled in marine and coastal environments, many marine scientists say.