Well... the bit about this not being news is certainly true (many species of bacteria eat oil and (especially) natural gas, so one more is nothing spectacular), but as to the rest... that's kinda true, kinda not. First off, the bacteria only eat certain components of the oil readily, while the more difficult to digest components sit around for a long time until something gets desperate enough to eat them. Second, oil on the surface is eaten much faster than oil that's floating deep under the water at ~4 degrees C. So surface oil disappears quite quickly, while underwater oil can take quite a while. Thirdly, those bacteria only live in the water for the most part. Once the oil hits the shores, it can sit for very, very, very long periods of time (10's of thousands of years in the worst conditions, decades in good conditions).

Gopher65talk16:52, 5 October 2010