The ocean is full of plastic. Not big pieces of plastic, as you've probably heard, but tiny bits of plastic. Microplastic. Plastic that hasn't decomposed, but broken down into small pieces that are incredibly durable. We've found this stuff throughout the world's oceans, at every depth. What kind of environmental impact does it have?
Citations of George Carlin on the subject of plastics aside, if and when the critters figure out how to eat this stuff, that might some disasters in the packaging industry when ketchup, salsa and sriracha bottles start disintegrating on supermarket shelves.