Two large warm water eddies are swirling to the north of the Gulf Stream current in this satellite image. Blue colors show cooler water, while yellow and orange colors show warmer water.
Click on image for full size
Courtesy of the Ocean Remote Sensing Group, Johns Hopkins University Applied Physics Laboratory
The Swirling Water of Ocean Eddies
Sometimes water spins away from a surface ocean current. This makes an eddy.
The center of some eddies is cooler water while the center of others is warmer water. There isn’t as much marine life or as many nutrients in warm water eddies as there is in cold water eddies.
Eddies are made when a bend in a surface ocean current makes a loop that breaks away from the current. The Coriolis effect makes eddies to rotate in different directions in the different hemispheres. Cold water eddies to rotate counterclockwise and warm water eddies to rotate clockwise in the Northern Hemisphere. In the Southern Hemisphere it is just the opposite. Once an eddy forms, the swirling waters last for at least a few months.
The image at the left, taken from a satellite high in the sky, shows two large circles above the Gulf Stream current in the Atlantic Ocean. These are eddies. In this image, surface water is colored depending on its temperature. Cooler water is shown with blue and purple and orange and yellow show warmer water. The orange color of these eddies means that they are warm water eddies. The Gulf Stream can have some of the largest and most well defined eddies in the world.
Shop Windows to the Universe Science Store!
The Summer 2010 issue of The Earth Scientist
, available in our online store
, includes articles on rivers and snow, classroom planetariums, satellites and oceanography, hands-on astronomy, and global warming.
You might also be interested in:
The water at the ocean surface is moved by powerful wind. The wind is able to move the top 400 meters of the ocean. This moving water is called surface ocean currents. Surface ocean currents form large...more
The winds in the Southeast Pacific mainly blow from south to north. They affect the weather and climate in the region. They also affect the climate in other places around the world. Air near the equator...more
There are many connections between the ocean and the atmosphere in the Southeast Pacific Ocean. Strong winds blow north along the coast of South America. These winds stir up the ocean. That brings cold...more
An aquifer is the name for a layer of rock which is capable of holding a large amount of water. Some layers are better at holding water than others, for example a layer of sandstone can hold a good deal...more
Limestone is an example of a carbonate. Other examples of carbonates include calcite, dolomite, and marble. Limestone dissolves easily in rainwater, especially rainwater which is loaded with carbonic acid....more
The deep ocean waters are under pressure and are much colder than layers of the ocean which are closer to the surface. Dissolved carbon dioxide seems to be absent from the deep ocean water and as a result...more
Have you ever left a glass of water out for a long time? Did you notice that the water disappears after a few days? That's because it evaporated! Evaporation is when water passes from a liquid to a gas....more