Everyone knows of the El Nino current that affect global climate and is a major cause of extreme climatic conditions. But scientists have recently discovered, in waters south of the Equator, previously unknown features of giant eddies of spinning water that have a huge impact on both climate and marine life.
These massive whirlpools, which can be thousand of kilometers across and go as deep as 500 meters, are called gyres.Because of their swirling motion the water trapped in the gyres is retained within their structure and does not mix with the surrounding water. For this reason they retain the animals, plants, pollution and nutrients within themselves and become a kind of limited eco system that turns into a barrier for the movement of the surrounding water. This barrier can be strong enough to even change to course of major ocean currents.
These fixed barriers are like a kind of skeleton for the oceans of the world. Just as the human skeleton shapes the body, the gyres shape the way the water flows in the ocean, which in turn affects climates. One of the best known gyres is associated with the Gulf Stream in the North Atlantic. This gyre directs the current towards Europe, where it pumps out heat and gives the region its relatively mild climate. To understand the effect it has, compare the climate of Portugal to that of Nova Scotia in Canada which is at the same latitude but has a much colder climate.
After releasing heat into the atmosphere of Europe, the gyre spins the water towards the equator where it again picks up heat and swings back to rejoin the Gulf Stream. Gyres play an important role in pumping heat from the Equatorial regions towards the polar areas and thus ensure the climate change from the Equator to the poles is gradual.
The nutrients trapped in the gyres provide a stable feeding area for marine life, both at the depths and near the surface. The spinning motion of the water in the gyre pushes the nutrients to the surface from where it is easily available to most forms of aquatic life
