I was just reading an article regarding this somewhere. there is a team of scientists there now trying to evaluate what is actually going on and how the bits of plastic are effecting the phytoplankton. In the article it said that most of the bits of plastic are nearly microscopic in size, and you would be hard pressed to actually see it. Note in the video that a lot of the debris is along the shore, and the gyre is mid-ocean, no land in sight.