By now, we've all seen pictures of oil from the Deepwater Horizon disaster [3] washing up on the shore, we've seen photos of the slick from the air and the video of the pipe gushing oil on the ocean floor. We've even seen the spread of the oil in the Gulf as time progresses, thanks to Google's Crisis Response [4] site for the spill. But what we haven't seen, until now, is the underwater impact of the oil geyser, and the effect of the chemical dispersants [5] BP [3] is using on the oil. ABC news went underwater with Philippe Cousteau, Jr., the grandson of the famous ocean explorer Jacques Cousteau, to film what the spill looks like underwater. After witnessing what looks like huge, dark brown-colored clouds of oil-and-water emulsion floating under the surface, Cousteau observed, "This is a nightmare ... one of the most horrible things I've seen under water." Click to view the video and see what's happening under the surface of the Gulf -- something BP [3] would rather you not see, particularly since BP CEO Tony Hayward [6] is disputing [7] claims that plumes of oil exist in the water column.