A strange, calm sea in the middle of the Atlantic — the only sea on Earth with no coastline, bounded instead by ocean currents.
Area
3,500,000 km²
Ocean basin
Atlantic
Location
The only sea with no land borders
Average depth
about 5,000 m
Maximum depth
about 6,000 m
Salinity
~36 ppt
Temperature
Warm, 18–28°C
Region
Mid North Atlantic
About the Sargasso Sea
The Sargasso Sea sits within the North Atlantic, ringed not by land but by four great ocean currents that circle it. Its still, deep-blue water is famous for floating mats of sargassum seaweed that shelter baby sea turtles, crabs and fish. Mysteriously, European and American eels travel thousands of kilometres to breed here and nowhere else.
Did you know?
It is the only “sea” defined not by land but by currents, and it floats with golden rafts of sargassum seaweed found nowhere else in such amounts.
Highlights
- The only sea with no land borders
- Floating rafts of sargassum seaweed
- The sole breeding ground of Atlantic eels
Photo gallery
Life in the Sargasso Sea
Creatures, seabirds and marine plants — including some of the rarest and strangest — that live in these waters.
Creatures of the deep
Portuguese man o’ war
Not one animal but a drifting colony, trailing venomous tentacles metres below its gas float.
Immortal jellyfish
A jellyfish that can rewind to its youthful stage, in theory cheating death forever.
Leatherback turtle
The largest sea turtle, diving over 1,000 m in pursuit of jellyfish.
Marine plants & algae
Sargassum
Free-floating golden seaweed that forms the living raft of the Sargasso Sea.
Surface & deep in the Sargasso Sea
The sea is warm where the Sun reaches it and cold far below. Flip between the sunlit surface and the deep water to feel the difference — these are typical figures for a sea.
Sunlit surface
22°C
typical surface temperature
Seas warm strongly at the surface in summer, but their deeper water stays cold and still — the sunlight simply never reaches it.
Recorded range for the Sargasso Sea: Warm, 18–28°C