Diving deep into the Gulf Stream

PHOTO: PER EIDE/SAMFOTO/THE INTERNATIONAL POLAR YEAR

Hooded seals, named for the strange inflatable "hood" on the male's head, are found throughout the North Atlantic. Their favourite food is octopus, and they often dive over one kilometre down into the icy cold waters to find these tasty morsels. Because Simon can dive so deep, he is the perfect assistant for climate researchers.

Engine made of ice

The Gulf Stream is a powerful sea current that flows off the coast of northern Europe, carrying warm seawater northward in the Atlantic Ocean. The Gulf Stream helps to make the climate this far north more comfortable.

But where does all the water go? When the Gulf Stream approaches the North Pole, the ice there cools down the salt water flowing from the south. Because of all the salt, the water becomes heavier and sinks to the bottom of the Atlantic Ocean. Then the cooled water begins to flow back toward the southern latitudes.

In this way, warm seawater is drawn northward along the ocean’s surface, while the cold water flows in the opposite direction deep down in the ocean. Put simply, the Gulf Stream is a circuit of water whose "engine" is the Arctic ice.

Satellite surveillance

But the Arctic ice is showing signs of melting, and researchers are wondering what effect this is having on the Gulf Stream. To find out, they have attached a small measuring device to Simon and about ten other seals. As Simon swims around the North Atlantic and dives for octopus, the measuring device sends information to the researchers via satellite. Researchers can then track how Simon is doing and what is happening to the Gulf Stream.

Published in 'Nysgjerrigper' no. 1/08

Translated by Connie Stultz