Sub-surface Oil Traces in Gulf
NOAA's independent analysis of water samples provided from the 22nd to 28nd May research mission of the University of South Florida's R/V Weatherbird II confirmed the presence of very low concentrations of sub-surface oil and PAHs (polycyclic aromatic hydrocarbons) at sampling depths ranging from 50 metres to 1,400 metres.
The Weatherbird II samples came from three stations: 40 and 42 nautical miles to the northeast of the well head and 142 nautical miles southeast of the well head (see chart). NOAA's analysis of the presence of subsurface oil determined that the concentration of hydrocarbons is in the range of less than 0.5 parts per million, and PAH levels in range of parts per trillion. NOAA announced its analysis in conjunction with the University of South Florida today.
Along with its analysis for the presence of oil and PAHs, NOAA's tests to "fingerprint" the Weatherbird II oil samples to the BP oil spill source concluded that:
•Hydrocarbons found in surface samples taken at the Slick 1 source, 40 nautical miles northeast from the well head, were consistent with the BP oil spill source;
•Hydrocarbons found in samples from Station 07-42 nautical miles northeast from the well head-at the surface, at 50 metres and at 400 metres are petroleum-derived but in concentrations too low to confirm the source; and
•Hydrocarbons found in samples taken from Station 01, 142 nautical miles southeast of the well head, at 100 metres and 300 metres were not consistent with the BP oil spill source.
An additional analysis of samples taken from waters 1,250 metres deep and 1,000 deep at two stations closer to the well are consistent with the findings of the University of South Florida. Our preliminary results revealed petroleum hydrocarbons so highly fractionated that it was not possible to confirm the source of the oil.
"We have always known there is oil under the surface; the questions we are exploring are where is it, in what concentrations, where is it going, and what are the consequences for the health of the marine environment?" said NOAA Administrator Dr. Jane Lubchenco. "This research from the University of South Florida contributes to this larger, three-dimensional puzzle we are trying to solve, in partnership with academic and NOAA scientists."
Other NOAA research missions that are conducting important research on sub surface impacts include the NOAA Ship Thomas Jefferson, a 208-foot survey vessel, which is currently underway on a mission in the vicinity of the BP Deepwater Horizon oil spill. Researchers are taking water samples and testing advanced methods for detecting submerged oil while gathering oceanographic data in the area's coastal waters. The NOAA Ship Gordon Gunter, a 224-foot research vessel, returned 3rd June from an eight-day oil detection mission in the vicinity of the BP Deepwater Horizon well head. During the effort, researchers collected water samples, conducted plankton tows, and employed echo sounders, autonomous underwater vehicles and other technologies to collect subsurface data. In addition, NOAA's P-3 "Hurricane Hunter" is deploying instruments to better track the movement of the Loop Current, and therefore improve our understanding of where the oil is moving at the surface and below the surface.
"NOAA's analysis of the Weatherbird II samples shows that concentrations of hydrocarbons decrease with depth, with a notable exception of samples at 300 metres from Station 07, which warrants additional research attention," said Dr. Steven Murawski, chief scientists for NOAA Fisheries. "Also, PAH levels are very low in all samples, with only five of 25 having reportable concentrations of the priority pollutant PAHs."
"We are deeply concerned about what this oil spill means for the health of the Gulf of Mexico, and for the millions of people who depend on these waters for their livelihoods and enjoyment," said Dr. Lubchenco. "NOAA is using all the scientific methods at our disposal to assess the damage, from satellites in space, planes in the air, boats on the water, gliders under the sea, scientists in the field, and information online."
