Graphic from WHOI Website
Scientists at the Woods Hole Oceanographic Institution (WHOI) detected and characterized a plume of hydrocarbons that is at least 22 miles long and more than 3,000 feet below the surface of the Gulf of Mexico, a residue of the BP Deepwater Horizon oil spill.
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. . . 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).
Recently, tests conducted by scientists at the University of South Florida show one of the plumes found that not only has oil settled to the ocean bottom further east than originally thought, but is at levels toxic to marine life. Sediment samples from DeSoto Canyon, a nutrient rich spawning ground for several important fish species off the western coast of Florida, showed oil present at deadly levels.
As I understand it, the plumes were caused due to the depth of well and the use of dispersants. As the crude oil gushed from the damaged well, the dispersants blasted the oil into its components parts. Some components rose to the surface and were taken landward by wave action. Other, perhaps heavier, components stayed under the thermocline, a transition layer between the mixed layer at the surface and the deeper water. These plumes never reached the surface. Yet, they are the most troublesome to coral, whales and other mammals of the deep.
We must track these plumes and remediate their destructive influences on dissolved oxygen levels, coral life, breeding grounds for fish and other sensitive areas. Stay tuned, I'll keep you posted.