I would imagine if they live at the deepest depths of the ocean it wouldn't even phase them. I feel like the analogy of us and space is pretty accurate. Satellites and space trash don't bother us much as they are so far above.
Nah there is trash tons of trash at the bottom of the ocean. When James Cameron went to challenger deep they found plastic bags at the bottom.
Not all of our debris floats. Trash has been found on the ocean floor.