Research continues on massive underwater oil plume
By Summit Voice
SUMMIT COUNTY — Is the oil gone from the Gulf of Mexico?
Hardly, according to the latest update from the unified command center, which reported that 126 miles of shoreline are seeing moderate to heavy oil impacts. That includes 111 miles of shoreline in Louisiana, 10 miles in Mississippi, 3 miles in Alabama, and 2 miles in Florida.
Another 500 miles of shoreline, including 112 miles in Florida, are classified as experiencing light to trace oil impacts—about 229 miles in Louisiana, 94 miles in Mississippi, 64 miles in Alabama, and 112 miles in Florida.
Those figures don’t include vast quantities of oil that’s hovering 3,000 feet deep in the Gulf, according to scientists at the Woods Hole Oceanographic Institution who detected a plume of hydrocarbons that is at least 22 miles long, 1.2 miles wide and 650 feet high.
The researchers said they don’t know of the plume represents a significant environmental threat.
“We don’t know how toxic it is,” said marine geochemist Christopher Reddy, an oil spill expert who co-authored the study. And we don’t know how it formed, or why. But knowing the size, shape, depth, and heading of this plume will be vital for answering many of these questions.”
The researchers detected a class of petroleum hydrocarbons at concentrations of more than 50 micrograms per liter. The water samples collected at these depths had no odor of oil and were clear.
“The plume was not a river of Hershey’s Syrup,” said Reddy. “But that’s not to say it isn’t harmful to the environment. These results indicate that efforts to book-keep where the oil went must now include this plume,” he added.
The article based on the peer-reviewed research appeared in the Aug. 19 issue of the journal Science.
The researchers chemically tracked the source of the oil as BP’s blown-out Macondo well. They reported that deep-sea microbes were degrading the plume relatively slowly, and that it was possible that the plume will persist for some time.
Subsequent research by the federal Lawrence Berkeley National Laboratory suggests that there might be a previously unknown strain of microbe helping to break down the oil at depth. Scientists involved in monitoring the deep sea oil plume said the two reports don’t necessarily conflict with each other. Both provide pieces to the puzzle of understanding what is happening to the millions of gallons of oil that spilled into the Gulf. The lab disclosed in its press release that some of its oil spill-related research was funded by BP.
The WHOI team based its findings on some 57,000 discrete chemical analyses measured in real time during a June 19-28 scientific cruise aboard the R/V Endeavor, which is owned by the National Science Foundation (NSF) and operated by the University of Rhode Island. They accomplished their feat using two highly advanced technologies: the autonomous underwater vehicle (AUV) Sentry and a type of underwater mass spectrometer known as TETHYS (Tethered Yearlong Spectrometer).
“We’ve shown conclusively not only that a plume exists, but also defined its origin and near-field structure,” said Richard Camilli of WHOI’s Applied Ocean Physics and Engineering Department, chief scientist of the cruise and lead author of the paper. “Until now, these have been treated as a theoretical matter in the literature.
“In June, we observed the plume migrating slowly [at about 0.17 miles per hour] southwest of the source of the blowout,” said Camilli. The researchers began tracking it about three miles from the well head and out to about 22 miles (35 kilometers) until the approach of Hurricane Alex forced them away from the study area.
The plume has shown that the oil already “is persisting for longer periods than we would have expected,” Camilli said. “Many people speculated that subsurface oil droplets were being easily biodegraded. Well, we didn’t find that. We found it was still there.”
The study—which was enabled by three NSF RAPID grants to WHOI scientists with additional funding from the U.S. Coast Guard—confirms that a continuous plume exists “at petroleum hydrocarbon levels that are noteworthy and detectable,” Reddy said. The levels and distributions of the petroleum hydrocarbons show that “the plume is not caused by natural [oil] seeps” in the Gulf of Mexico, Camilli added.
Filed under: BP Gulf oil spill, Environment, Summit County Colorado Tagged: | Gulf of Mexico, Lawrence Berkeley National Laboratory, National Science Foundation, Oil spill, Woods Hole Oceanographic Institution