The North Atlantic is a location in DEXTER. After the incident in the Bay Harbor Butcher Investigation where Dexter Morgan's stashing ground for body parts was found by a scuba diving group, Dexter investigates a new possibility for him to dump bodies and he discovers the Gulf Stream. According to him, this powerful current will carry body parts deep within its water all the way up to the North Atlantic and according to Dexter, "it's a pretty big place".
This is the presumed destination of all body parts belonging to victims on their journey through the country from Miami, Florida. Unless caught on something, they will be pushed this far and spill out into the sea to be lost forever or taken care of by wild-sea life. So far none of the body parts have been located and if they were, there is not enough evidence to link them to coming from Miami.