UCSB geography professor David Valentine and colleagues have received a grant from the National Science Foundation to measure and manage the damage caused by the Gulf Oil Spill during a 10-day cruise.
Oil has been spilling into the Gulf of Mexico since the Deepwater Horizon oil rig sank last month. After questionable reports projected that 5000 or more barrels were leaking per day, Valentine discovered an innovative method for more accurate measurement by assessing methane concentration.
Methane is easier to track than oil and comprises 40 percent of the material spilling into the Gulf. When methane bubbles rise to the water’s surface, they dissolve and form an easily measured plume.
Valentine said, because of its consistency, methane can be measured empirically and potentially provide a more stable estimate of the damage than a measurement of oil.
“The natural gas dissolves. The oil doesn’t, so it’s impossible to round up,” Valentine said. “Because the methane is dissolved in the water, it has much nicer behavior and we merely need to sample the water. The measurements are fairly simple for methane and we can pick out a signal very easily.”
Compared to other methods currently in use for determining the damage caused by the oil, Valentine said he thinks his approach can adapt to the shifting nature of the spill.
“I think this one has an advantage because it tells you a total amount that has been emitted,” he said.
“Other methods give an instantaneous flow rate — which is not a constant figure — that could have been different a day or a month ago. What [our method] will provide is a reasonable minimum value for the total emission.”
However, environmental science professor Josh Schimel noted that a number of measuring styles will be necessary to ensure an accurate assessment.
“It wouldn’t surprise me if [Valentine] could get a number that’s plus or minus a factor of two,” Schimel said. “But we need to use several different approaches to see if they converge on some common estimate … Normally, we deal with tanker spills and we know exactly how much oil was in the tanker so it’s interesting because with this one, we don’t know.”
Valentine’s work will be published in the weekly science journal Nature tomorrow.