Which Atlantic sea is defined by ocean currents rather than land boundaries?

The Sargasso Sea is the Atlantic sea defined by ocean currents rather than land boundaries.

It occupies a broad region of the North Atlantic and is bounded by four major currents: the Gulf Stream to the west, the North Atlantic Current to the north, the Canary Current to the east, and the North Atlantic Equatorial Current to the south. Unlike most named seas, it has no coastline.

The sea is named for Sargassum, a floating brown seaweed found in large mats on its surface. Portuguese sailors encountered the weed during early Atlantic voyages and called the region the Sargasso Sea. The floating habitat supports juvenile eels, sea turtles, seabirds, and many small marine organisms.

The Sargasso Sea is often confused with the Bermuda Triangle because both are associated with the western North Atlantic, but they are not the same region. The Bermuda Triangle is an informal geographic label, while the Sargasso Sea is an oceanographic region established by circulating currents.