North Atlantic Gyre

The North Atlantic Gyre of the Atlantic Ocean is one of five great oceanic gyres. It is a large circular ocean current that stretches from the Intertropical Convergence Zone, also called the doldrums, to the area south of Iceland. It reaches from the east coasts of North America to the west coasts of Europe and Africa.

The gyre is made up of several smaller currents. The Gulf Stream flows northward along the west, followed by the North Atlantic Current across the north. The Canary Current moves southward along the east, and the North Equatorial Current flows in the south. This system helps move salty water west from the Mediterranean Sea and then north to form the North Atlantic Deep Water.

One important feature of the North Atlantic Gyre is the Sargasso Sea, located at its center. This area is known for its calm waters and large amounts of seaweed.

Unfortunately, the gyre also catches human-made marine debris, creating a natural garbage or flotsam patch, similar to the Great Pacific Garbage Patch found in the North Pacific Gyre. This shows how ocean currents can affect the movement of waste in the sea.

Structure

Cold air at high latitudes makes the ocean lose heat. This makes the water denser and creates deep currents. In winter, when the temperature difference between the sea and air is greatest, this effect is strongest. Much of this dense water flows southward over a ridge called the Greenland-Scotland Ridge. Some goes through the Denmark Strait and others through nearby channels.

This cold, dense water mixes with other water masses as it moves along the ocean floor. It follows a path around the Labrador Sea and can pick up more water from this area. The amount of this deep water depends on how much cold air there is and can change from year to year. Scientists are still learning exactly how these deep currents connect to larger ocean patterns.

Seasonal variability

The North Atlantic Gyre changes with the seasons. During the Northern Hemisphere winter, it stretches more from east to west and becomes thinner from north to south. In summer, the gyre moves a little south.

In the Sargasso Sea, scientists have found that these changes are linked to mixing of water during winter. The surface temperature can change by about 8-10 °C between winter and summer. In winter, mixing brings nutrients from deeper water to the surface, which helps ocean plants grow. This mixing also affects the amount of carbon dioxide in the seawater.

Lead contamination

Scientists looked at tiny bits of air, sea particles, and water from the North Atlantic Gyre between 1990 and 1992. They studied special types of lead to learn where pollution came from. They found pollution came from Europe and the Middle East, carried by winds, and from America. Even though the United States used less lead in fuels, a lot of the pollution in the surface water of the Sargasso Sea still came from American factories and cars. After 1992, the amount of lead in the water started to go down, and scientists think this will keep happening across the Atlantic's surface layers.

Garbage patch

The North Atlantic Gyre is a large circular current in the Atlantic Ocean. It helps move water from near the equator up towards areas south of Iceland. It also moves water from the east coasts of North America to the west coasts of Europe and Africa. This gyre is made up of several smaller currents. These include the Gulf Stream, which flows north along the western side, and the Canary Current, which flows south along the eastern side.