This illustration shows a plume of hydrocarbons emanating from the Deepwater Horizon oil spill. The plume was identified using the autonomous underwater vehicle (AUV) Sentry, instrumented with a TETHYS mass spectrometer. The vehicle made numerous criss-cross penetrations to map the parameters of the 1,100-meter-deep plume. Woods Hole Oceanographic Institution (WHOI) scientists, who conducted the NSF-funded work in June 2010, report the plume they measured was 1.2 miles wide and 650 feet high. WHOI developed and operates Sentry.