Weird. Oil raises when it is in water. Its not as dense as salt water.
:/ we should have giant fields of oil slicks everywhere in the gulf if the numbers are correct...right?
Well it's got a huge area/volume to compare with and the plume could get split into a number of tendrils as is rises toward the surface...I imagine, anyway.
...Not to mention the dispersal efforts whose basic function is to make the stuff seem to disappear by spreading it around. It worked for me as a young lad whenever I wanted to make it seem like I had eaten more of my dinner than I had, and that was a much larger numerator and a much smaller denominator.