An explosion on the BP-operated Deepwater Horizon oilrig in the Gulf of Mexico on April 20. 2010 and the subsequent oil spill for nine months has become one of the second-most presented, discussed and publicized environmental catastrophe in the last decades (the first would be Chernobyl).
Politicians, authorities and experts referred to the accident as "unprecedented" and were insecure of the amount of oil spilled, the area affected and the effects of the oil on the marine environment. One of the surprising consequences of an oil leak in 1.200m depth were large subsurface oil plumes, whose existence were first doubted or even denied.
Fig.1. The oil slick as seen from space by NASA's Terra satellite on May 2. 2010 (image from Wikipedia).
This posed a major problem in the estimation by traditional methods - areal or satellite images - of the oil amount released into the gulf.
The oil on the surface was more visible and BP tried to deny it, entrap it, burn it or disperse it with chemicals, however despite the efforts on April 29. first oil traces were spotted on the US-coast, which caused an immediate and immense media response.
The Deepwater Horizon accident is however not completely unprecedented, in 1979 a blowout from the Ixtoc I platform in the Bay of Campeche released for nine months in sum 454.000-480.000 tons of oil into the water - the world's largest peacetime oil spill until the Deepwater Horizon accident with estimated 500.000-627.000 tons.
Many of the effects and problems observed at the Ixtoc I accident however were seemingly forgotten, as it seems that today the consequences of the Deepwater Horizon accident are already forgotten.
JERNELÖV, A. (2010): The Threats from Oil Spills: Now, Then, and in the Future. AMBIO 39:353-366
SAFINA, C. (2011): The 2010 Gulf of Mexico Oil Well Blowout: A Little Hindsight. PLoS Biology 9(4): 1-5