Science journalist Mark Schrope is aboard the research vessel Pelican, which is spending the week studying the Deepwater Horizon oil spill in the Gulf of Mexico. Check back to The Great Beyond for daily mission updates.
This morning we returned to four sites within the newly mapped plume, and one outside, to get repeat readings and collect additional water samples. The team found some intriguing changes, but explaining them will take some time. “It seems to be a very dynamic plume,” says National Institute for Undersea Science and Technology chief scientist Arne Diercks, “Some of the intensities went down, and at some spots we found the plume at depths we didn’t have it before.”
Earlier today the Environmental Protection Agency approved application of dispersant at the wellhead. During tests of this new technique over the past few days, BP added over 100,000 litres of dispersant at depth. So, it’s not clear whether the NIUST plume, assuming tests confirm it’s oil, is strictly dispersed oil from these tests or whether some portion of it is heavier components of the crude oil that separated as the oil spread and rose to the surface. Or the answer may be somewhere in between.
While the plume work came to dominate the mission, it was far from the only task underway. University of Southern Mississippi graduate student Dong-Joo Joung (right), for instance, has been diligently taking samples that he will analyze for trace metal concentrations. His goals will be to measure the trace metals the oil spill may be adding to the water and to determine if the oil has a trace metal signature that can be used to track the remnants of the oil spill over the long term.
Joung also had the job of taking measurements of how light was reflecting off the ocean at various sites. These data will ultimately be used to ground truth a NASA project underway to use high-altitude infrared imaging to track the oil.
One overarching lesson from the cruise is that oil’s behavior is more complex than the team anticipated. “I expected the oil to simply float to the surface and spread in a big slick,” says NIUST oceanogapher Vernon Asper, “I was really surprised that oil has so many different forms.”
Even though their list of goals evolved and lengthened as the cruise progressed in response to those complexities, and colleagues’ requests, the team was still able to accomplish everything it set out to do. "I think these two weeks were highly successful, says NIUST chief scientist Arne Diercks. “Everybody worked pretty hard on this trip to get this done.” That, I can confirm.
The team has gathered critical sediment samples that can be used as a baseline for future studies of whether oil eventually makes it to the seafloor in substantial quantity and if so what the effects might be. Creating this and other baselines simply wouldn’t have been possible had the team not managed to make it to the accident zone so quickly.
And, of course, they got early information about a plume nobody even knew existed, and water samples that will eventually tell much more of the story about where the oil is going and what effects it might have in the water column.
All of that information will be crucial as this team and others work over the coming months and even years to study the impacts of the spill, but this is just a start. Given the complexity of the oil and the ocean, combined with the sheer volume of oil that’s been released, it’s clear that adequately studying what’s going on out here will be a Herculean task.
Posted on behalf of Mark Schrope
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