Sargasso Sea without a coastline

The Sargasso Sea is in the middle of the Atlantic Ocean, between the West Indies and the Azores, covering some 2 million square miles (3 million sq km). Jules Verne wrote about it in “Twenty Thousand Leagues Under the Sea”.

The Sargasso Sea is encircled by the The Gulf Stream and the North Equatorial Current, causing the oval-shaped sea to move in a slow, clockwise drift. The water is exceptionally blue, with a high salt content.

Its warm waters are exceptionally clear and blue, and filled with seaweed. Early navigators becalmed in the sea’s still waters mistakenly believed their ships were tangled in the seaweed. They named the sea “sargaco”, the Portuguese word for grape, after the seaweed’s bulbous floats.

The Sargasso Sea is also known as “the floating desert”. Although about one-third of the Atlantic’s plankton is produced here, the Sargassum lacks the nutrients to attract commercially valuable fish. But many small marine animals, including tiny crabs, shrimp and octopuses, live on and among the sargassum, the rootless weed. Deeply connected to the weeds, many would sink and perish if they lost their grip. The Sargasso Sea is 5km (3 miles) deep, thus the sargassum grow by budding.

The Sargasso also is an international meeting place for eels. Drawn by unknown forces, the snakelike fish come from Europe, the Mediterranean and the United States to mate, spawn and die. From there, their larvae make the long journey back to continental waters.

Video : Genomics pioneer Craig Venter on the ocean’s biodiversity, including the 2,000 photoreceptor genes found in the Sargasso Sea

Book: A Sea within a Sea