(AG / 23-08-10)  “The spill of the BP broken oil well released a column of hydrocarbon of over 35 km. long and 200 m. high, located at 1,100 meters depth”, according to a study published in magazine “Science” says agency Efe.

The study, carried out by the prestigious Oceanographic Institution Woods Hole (WHOI), says that the explosion and sinking of the dig Deepwater Horizon last April caused a column of waste whose natural degradation is very slow.

The WHOI team based its findings on some 57,000 chemical analyses measured in June during an expedition aboard a submarine able to explore the ocean until 4,500 m. deep.

“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. “Until now, these have been treated as a theoretical matter in the literature.”

Camilli, chief scientist of the cruise and lead author of the paper, added that the hydrocarbon levels are “noteworthy and detectable”.

The team crisscrossed plume boundaries continuously 19 times to help determine the trapped plume’s size, shape, and composition. During the tour, they sampled through a ocean tool that measures conductivity, temperature and water depth.

Once in the laboratory, they checked that the samples, although colourless and odourless, contained concentrations of hydrocarbons, including benzene, toluene, etibenzene and xylene of over 50 micrograms per litre.

THE GOVERNMENT SAYS THAT THE 74% HAS DISSAPEARED

This conclusion contrasts with that obtained by the U.S. government, which last August 4 presented a scientific report according to which 74% of the 4.9 million barrels of oil that spilled into the ocean since April has been collected, burned, evaporated or decomposed by natural processes.

“Many people speculated that subsurface oil droplets were being easily biodegraded. Well, we didn’t find that. We found it was still there,” said Camilli.

However, the scientists found no “dead zones,” regions of significant oxygen depletion within the plume where almost no fish or other marine animals could survive. WHOI geochemist Benjamin Van Mooy, also a principal investigator of the research team, said this finding could have significant implications.

“If the oxygen data from the plume layer are telling us it isn’t being rapidly consumed by microbes near the well,” he said, “the hydrocarbons could persist for some time. So it is possible that oil could be transported considerable distances from the well before being degraded.”