St. Petersburg, Fla.- Researchers at the University of South Florida’s College of Marine Science and the National Oceanic and Atmospheric Administration announced today that layers of degraded oil found in the subsurface of the northern Gulf of Mexico cannot be directly linked to the Deepwater Horizon spill until further research is conducted.
“We have not concluded our comparison of the oils,” said Ernst Peebles, USF’s lead scientific investigator on the R/V Weatherbird II cruise. “Preliminary results show similarities at least at the surface.”
The oil found was in the form of weathered emulsified oil, or “mousse”, and in invisible oil particles, which are not visible to the naked eye. Emulsified oil forms particles that have a brown or orange exterior and a chocolate-colored interior, and have been referred to as “tar balls”.
The emulsified oil encountered at (see graphic) stations DSH07, DSH08, and DSH_slick1, was observed floating at the surface under calm conditions. Large numbers of the smaller-sized emulsified oil was observed to be suspended at least 10 feet below the surface.
The invisible oil particles collected among emulsified oil particles, were determined by the NOAA scientists to have originated from the Deepwater Horizon site.
During a May 22-28 cruise on the R/V Weatherbird II, USF scientists, using sonar and particle-senor data, discovered degraded oil suspended at depths of 400 meters (one-quarter mile) and 1,000-1,400 meters (two-thirds to three-quarters of a mile) beneath the Gulf’s surface in the form of small particles or droplets.
The 400-meter layer was approximately 30 meters (100 feet) thick, and was observed to extend for at least 45 nautical miles northeast of the Deepwater Horizon site.
The deeper 1,000-1,400 meters layer had hydrocarbons that looked identical to the 400 meter samples but were at twice the concentration. According to the USF scientists, the origins of the hydrocarbons are likely from a deep-sea source.
