Earlier quoted context omitted.
Isn't this just the tip of the iceberg? Much of it is in a suspend emulsion that doesn't neccessarily match the surface outline.
Maybe. Regular oil floats to the surface. I'm not sure about all this crude however.
Until it forms into little tarballs, and then sinks below the surface of the water. Combined with the "safe" dispersant BP is using to thin the oil, it helps the whole sinking process go faster.
The size of this overlay is more so a depiction of the "core" spill. The slick above and below water extends to a much larger area, and also moves around daily.