Sat, Aug 21, 2010 page7

• Study shows oil plume lingers

  SILVER LINING The slow breakdown of the oil from the BP spill means that oil-eating bacteria have not consumed excessive amounts of oxygen

  • NEW YORK TIMES NEWS SERVICE
  • • 
    • 
    • 

  New research confirms the existence of a huge plume of dispersed oil deep in the Gulf of Mexico and suggests that it has not broken down rapidly, raising the possibility that it might pose a threat to wildlife for months or even years.

  The study, the most ambitious scientific paper to emerge so far from the Deepwater Horizon spill, casts some doubt on recent statements by the US federal government that oil in the gulf appears to be dissipating at a brisk clip.

  However, the lead scientist in the research, Richard Camilli, cautioned that the samples were taken in June and circumstances could have changed in the past two months.

  

  This sequence of handout images shows remotely operated vehicle still images taken during descent through the water column from a location less than 500m southwest of the Deepwater Horizon oil well site on June 1. The images were recorded from a forward-looking video camera. A highly turbid oil-emulsion layer was evident in the depth region between 1,065m and 1,300m, with small oil droplets temporarily collecting on the camera lens within this depth interval.

  PHOTO: AFP/ R. CAMILLI, WOODS HOLE OCEANOGRAPHIC INSTITUTION

  The paper, which was to appear in yesterday’s issue of Science, adds to a welter of recent, and to some extent conflicting, scientific claims about the status of the Gulf of Mexico. While scientists generally agree that the risk of additional harm at the surface and near the shore has diminished since the well was capped a month ago, a sharp debate has arisen about the continuing risk from oil in the deep waters.

  So far, scientific information about the Gulf of Mexico has emerged largely from government reports and statements issued by scientists. Many additional research papers are in the works, and it could be months before a clear scientific picture emerges.

  The slow breakdown of deep oil that Camilli’s group found had a silver lining: It meant that the bacteria trying to eat the oil did not appear to have consumed an excessive amount of oxygen in the vicinity of the spill, alleviating concerns that the oxygen might have declined so much that it threatened sea life. On this point, Camilli’s research backs statements that the government has been making for weeks.

  Camilli, of the Woods Hole Oceanographic Institution in Woods Hole, Massachusetts, said the plume, at the time he studied it, was dissipating so slowly that it could still be in the Gulf of Mexico many months from now.

  Assuming that the physics of the plume are still similar to what his team saw in June, “it’s going to persist for quite a while before it finally dissipates or dilutes away,” he said.

  Concentrations of hydrocarbons in the plume were generally low and declined gradually as the plume traveled through the Gulf of Mexico, although Camilli’s team has not yet completed tests on how toxic the chemicals might be to sea life.

  In an Aug. 4 report, a team of government and independent scientists organized by the US National Oceanic and Atmospheric Administration (NOAA) estimated that 74 percent of the oil from the leak had been captured directly from the wellhead; skimmed, burned, dispersed chemically or by natural ­processes; evaporated from the ocean surface; or dissolved into the water in microscopic droplets.

  The report found that the remaining 26 percent of the oil had mostly washed ashore or collected there, was buried in sand and sediment or was still on or below the surface as sheen or tar balls.

  While the government report expressed concern about the continuing impact of the spill, it was widely viewed as evidence that the risk of additional harm in the Gulf of Mexico was declining.

  For weeks, BP disputed claims from scientists that a huge plume of dispersed oil droplets had formed in the Gulf of Mexico, with its then chief executive Tony Hayward declaring at one point: “There aren’t any plumes.”

  NOAA, while initially skeptical, ultimately confirmed the existence of such plumes in two reports. The new paper appears to dispel any lingering doubt, providing detailed evidence that one major plume and at least one minor plume existed and that they contained large quantities of hydrocarbons, albeit dispersed into tiny droplets.
• Most Popular

  • 1

    Referendum, 26 recall votes could cost NT$1.62 billion

  • 2

    Conference on rebuilding Ukraine opens in Italy

  • 3

    Dispute between US, Brazil escalates

  • 4

    MOFA welcomes remarks by NATO’s Rutte

  • 5

    TSMC’s materials executive quits