Waters
Animals follow water, and water in the Atlantic is far from uniform. Four places explain a good deal of who lives where.
The Sargasso Sea
A sea with no coast. It is bounded by currents instead of land, and named for the floating sargassum weed that gathers in its calm centre. The weed mats shelter young turtles and fish, and European and American eels travel thousands of kilometres to spawn here.
The Grand Banks
Shallow underwater plateaus off Newfoundland where the cold Labrador Current meets the warm Gulf Stream. The mixing brings nutrients up into sunlit water and makes thick fog above it. For five centuries this was one of the richest cod fisheries in the world.
The Mid-Atlantic Ridge
An underwater mountain chain along the seam where two plates pull apart. In places hot, mineral-rich water vents from the seabed and supports shrimp, mussels and microbes that live on chemical energy instead of sunlight.
The Gulf Stream
A fast, warm current that leaves the Gulf of Mexico, follows the North American coast and turns east across the ocean. Its extension carries heat towards north-west Europe, and its edges are a highway for tuna, turtles and drifting larvae.