[D-fendr]

The oil on the surface, and the oil under the surface have to add up to the total flow out of the well, which is known.

Ok, how much is it and according to whom?

If the oil "fractionates" and breaks up into smaller particles, this is a GOOD THING

Oh? What chemicals does fractionation result in?

[Wonder Warthog]

"Ok, how much is it and according to whom?"

A consensus opinion seems to be 10,000 bpd. I put no credence in the "estimates" by NPR and others. They have no data to work from. BP and the Coast Guard do.

"Oh? What chemicals does fractionation result in?"

Uh, the same ones that came out of the well. All "fractionation" does is more or less separate them somewhat by density. However, the more fractionation and dispersion that happens, the less toxic the oil is, and the easier it is for the naturally-occurring bacteria who can metabolize it to do so.