g These images, created using microwave data from NASA’s Aqua satellite in 2007, show clearly the Gulf Stream’s effect on temperatures in the Atlantic throughout the year. Notice the dramatically cooler temperatures in the lee of Cape Hatteras, sheltered from the Stream’s northwesterly flow, especially in the autumn (bottom image).
g By June, warm seas have spread into the Gulf, and the Gulf Stream brings temperatures (dark blue) up to 10°C (50°F) in the farthest north of the Atlantic. g In January, surface temperatures (orange) reach 30°C (86°F) in the Caribbean. The Gulf Stream still takes the chill off the sea as it flows on past Cape Hatteras.
comfortable climates in the world. Without the Gulf Stream, Florida, which basks in almost tropical warmth, would be quite cool, and Britain would have a climate as chilly as Alaska, which is on the same latitude. And the Gulf Stream is even more important for marine life in the North Atlantic.
river out of africa
The origins of the current lie in central and north Africa, where the equatorial sun beats down all year. As the air warms, it plumes up, drawing in streams of air beneath it from far to the north and south as Trade Winds, which are deflected to the west by the spinning of the Earth. As the Trade Winds blow westward across the Atlantic, they drag the surface waters with them to generate a westward flow along the Equator – the North and South Equatorial Currents. It is the North Equatorial Current that drives the Gulf Stream, hitting South America and then, forced around in a great loop by the land masses around the Gulf of Mexico and the Caribbean, curling back round the southern tip of Florida to run out into the Atlantic again.
From here, the Gulf Stream flows like a giant warm river up the East Coast of the USA, sweeping along an estimated 80 million cu. m (2,800 million cu. ft) of water per second. Various eddies and counter currents split off as it drives on north to pass near the Grand Banks of Newfoundland, where it is deflected northeast across the Atlantic towards the British Isles. Where it begins off Florida, the Gulf Stream water is a balmy 23°C (73°F), and even as far north as Newfoundland it is still more than 17°C (63°F). When viewed on heat-sensitive infrared satellite pictures it shows up as a great red ribbon streaming northeastward. It is the largest and fastest warm current in the world, and a very special habitat for wildlife, delivering both warmth and nutrients.
the SuStaiNiNG Stream
Many species, such as sea turtles, use the Gulf Stream as a travelator to carry them swiftly along migration routes. Many, too, use it because of the way it generates food, as its eddies and collisions with cold water stir up the nutrients that stimulate plankton growth. That is why the summer waters off Carolina, that project right into the Gulf Stream at Cape Hatteras, are famous for their ‘sport’ fish, such as yellowfin tuna, grouper, rockfish, snapper, mahi mahi, and especially blue marlin, which all come to feed on the fish, such as baitfish, that in turn feed on the plankton. Where the northern edge of the Gulf Stream washes into the cold Labrador Current south of Newfoundland, the mixing of the waters creates what was once the world’s greatest fishery on the Grand Banks. The coastal waters of the British Isles are similarly enriched by the intermingling of the warm Gulf Stream and the colder Arctic waters, and species such as loggerhead and leatherback turtles journey here in the summer to take advantage of the bounty, hitching a ride on the Gulf Stream.
The atlantic
155 h The Gulf Stream keeps the British Isles unusually mild for their latitude. Any change in the current could make rare snow coverings like this on the famous Seven Sisters cliffs on the southeastern coast of England, in January 2010, much more common.
f Fragile and beautiful seahorses, like this short-snouted seahorse, are particularly vulnerable to habitat degradation, and they are now only seen rarely on the coasts of Europe.
\h Mutton snappers that live on the tropical Atlantic coast of the Americas are popular fish for the dinner table. Sold as ‘red snappers’, they are too popular for their own good and numbers have declined dramatically.
oceans as its importance would suggest. About 13,000 years ago, for instance, it suddenly changed direction for a while, plunging northwestern Europe into an Ice Age, and dramatically altering the distribution of ocean life. There are increasing concerns among scientists that global warming could trigger another change. If global warming heats the Arctic quickly enough to melt a substantial amount of the ice cap all year round, it could flood the North Atlantic with cold fresh water and stall the flow of the Gulf Stream in a matter of months. If so, the northeastern
USA and northwestern Europe could be snapped into an icy time lasting decades or even longer. Some scientists believe they have already detected a slight slowdown in the Gulf Stream, though others dispute their findings. The change, though, could come suddenly and without warning.