Follow up to postings on the Gulf Coast oil spill, news that “scientists at the Woods Hole Oceanographic Institution (WHOI) have detected 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 1.2-mile-wide, 650-foot-high plume of trapped hydrocarbons provides at least a partial answer to recent questions asking where all the oil has gone as surface slicks shrink and disappear. “These results indicate that efforts to book keep where the oil went must now include this plume” in the Gulf, said Christopher Reddy, a WHOI marine geochemist and oil spill expert and one of the authors of the study, which appears in the Aug. 19 issue of the journal Science. The researchers measured distinguishing petroleum hydrocarbons in the plume and, using them as an investigative tool, determined that the source of the plume could not have been natural oil seeps but had to have come from the blown out well. Moreover, they reported that deep-sea microbes were degrading the plume relatively slowly, and that it was possible that the plume had and will persist for some time. 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, which is owned by the National Science Foundation (NSF) and operated by the University of Rhode Island. 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).”