A quote from BP as taken from CNN refuting the rumor that some oil is just hanging in the middle of the ocean column in a “plume”, not sinking or floating immediately:
Now, crude oil is made up of lots of different hydrocarbons, some of which will float and some will sink. Are there any hydrocarbons, or mix of hydrocarbons, that can come from oil that will not sink or float right away? Could they be theoretical separated from the leak through natural processes and form a plume that way?
BP has been injecting dispersants into the oil as it escapes from the well, so that changes the specific gravity of the emulsion of dispersant, oil and water, so it no longer all floats to the surface.
yes the dispersant creates an emulsion. emulsions if left undisturbed might separate, though agitation will put the materials in suspension again.
vigorous agitation can be enough to create an emulsion without dispersant as an emulsifier.
Ever seen a lava lamp? What about a cloud? There are many things with different densities that easily form stable or metastable regions through convection or heating. Small enough particles have enough kinetic energy on there own to simply stay suspended indefinitely. Ever seen a glass of milk?
Like everything else coming out of BP, the comment is a bold lie.