To be precise, this mass is not really an island. The garbage itself floats just beneath the surface in a decaying soup that extends many feet below the surface in places. The mass is held together by oceanic currents called gyres. Also known as a trash vortex, this mass of mostly plastic doesn't discriminate. Large pieces mingle in a muck of tiny plastic bits broken down by the sun in a process called photo-degeneration. the main problem to why they cant get the garbage out o fhte ocean is because it would be a a problem to seperate the trash from the animals without harming or bothering them during the process.