BP says that more evidence is needed to prove scientists’ claims that oil is collecting in underwater plumes, according to the Associated Press. Over the weekend, BP CEO Tony Hayward said there is “no evidence” that oil is suspended beneath the surface, arguing that oil rises in water.
This contradicts observations from three different teams of researchers over the last few weeks identifying several large oil plumes in the Gulf, each miles wide and hundreds or thousands of feet deep. The plumes contain tiny droplets of oil — from the size of a thumbnail to the size of a golf ball, the Washington Post reported — that has dissolved into the water, perhaps due to the effect of chemical dispersants.
The government posted a map this week showing the location of one of the underwater plumes, according to the New York Times Wednesday. “This would seem to be the most detailed confirmation yet by a federal agency that the undersea plumes are real,” reported the Times.
But how could oil get trapped undersea in the first place — shouldn’t it float to the top, as Hayward argues?
Visualize salad dressing, said the Times Green Blog:
The usual expectation is that oil of any kind floats on water. But anybody who has ever shaken a vinegar-and-oil salad dressing knows it is not quite so simple. In the right conditions, oil droplets can get suspended in water. What’s happening in the Gulf of Mexico right now might turn out to be the mother of all salad dressings.
“We’ve been thinking that the recent news about underwater oil plumes is very reminiscent of these jet experiments, in which the effect of the strong turbulence is creating an emulsion which can lead to an underwater trapping,” McLaughlin said. “In videos of the actual oil leak in the Gulf, the turbulent oil jet looks quite similar to our alcohol jet.” He added that with the addition of dispersants, the effect would be further amplified.
But the salad dressing analogy only goes so far, according to scientist David Hollander at the University of South Florida. He found one plume that “is clear, with the oil entirely dissolved. ” From the Post:
“Here is a situation where, unless you’re looking at the chemical fingerprints, [the oil] is absolutely not visible,” Hollander said. “It’s not some Italian vinaigrette or anything like that. It’s absolutely, perfectly clear.”
Plumes would have a unique role in devastating marine life. The low levels of dissolved oxygen in and around the plumes could literally choke fish and other life. Dissolved oil could also accumulate in fish larvae and filter feeding creatures — which would then pass the toxin up the food chain to fish that include commercially important species like red snapper.
Underwater plumes could also be yet another reason BP and the government have underestimated volume of the spill.
According to the New York Times:
The undersea plumes may go a long way toward explaining the discrepancy between the flow estimates, suggesting that much of the oil emerging from the well could be lingering far below the sea surface.