NASA: The Thermohaline Circulation (The Great Ocean Conveyor Belt) [720p]

The oceans are mostly composed of warm salty water near the surface over cold, less salty water in the ocean depths. These two regions don't mix except in certain special areas. The ocean currents, the movement of the ocean in the surface layer, are driven mostly by the wind. In certain areas near the polar oceans, the colder surface water also gets saltier due to evaporation or sea ice formation. In these regions, the surface water becomes dense enough to sink to the ocean depths. This pumping of surface water into the deep ocean forces the deep water to move horizontally until it can find an area on the world where it can rise back to the surface and close the current loop. This usually occurs in the equatorial ocean, mostly in the Pacific and Indian Oceans. This very large, slow current is called the thermohaline circulation because it is caused by temperature and salinity (haline) variations.
This animation shows one of the major regions where this pumping occurs, the North Atlantic Ocean around Greenland, Iceland, and the North Sea. The surface ocean current brings new water to this region from the South Atlantic via the Gulf Stream and the water returns to the South Atlantic via the North Atlantic Deep Water current. The continual influx of warm water into the North Atlantic polar ocean keeps the regions around Iceland and southern Greenland mostly free of sea ice year round.

The animation also shows another feature of the global ocean circulation: the Antarctic Circumpolar Current. The region around latitude 60 south is the the only part of the Earth where the ocean can flow all the way around the world with no land in the way. As a result, both the surface and deep waters flow from west to east around Antarctica. This circumpolar motion links the world's oceans and allows the deep water circulation from the Atlantic to rise in the Indian and Pacific Oceans and the surface circulation to close with the northward flow in the Atlantic.

The color on the world's ocean's at the beginning of this animation represents surface water density, with dark regions being most dense and light regions being least dense (see the animation Sea Surface Temperature, Salinity and Density). The depths of the oceans are highly exaggerated to better illustrate the differences between the surface flows and deep water flows. The actual flows in this model are based on current theories of the thermohaline circulation rather than actual data. The thermohaline circulation is a very slow moving current that can be difficult to distinguish from general ocean circulation. Therefore, it is difficult to measure or simulate.

This animation first depicts thermohaline surface flows over surface density, and illustrates the sinking of water in the dense ocean near Iceland and Greenland. The surface of the ocean then fades away and the animation pulls back to show the global thermohaline circulation.

credit: NASA/Goddard Space Flight Center/UMBC

source: http://svs.gsfc.nasa.gov/goto?3658

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[lilaclila90]

how much time taken by the arrow(flow of water), to reach the same point, after it circulate in this great conveyor belt?

[djxatlanta]

- the answer to your question is in the second-to-last paragraph. =)

[88blockNS]

I've got a question. If you went far enough down into the ocean, would the current be visible? Like in the movie Finding Nemo? If so, is there any video footage?

[djxatlanta]

- I can't recall if I've seen videos of current, but I suggest doing a search on YouTube for something similar -- "brine pools" -- they are ponds of water discovered at the bottom of the ocean with a high salinity content that have their own flat surfaces and waves.

[findlesx]

The description is incorrect

The water in the depths is more salty, due to the arctic sea ice... Thats how the water drops and becomes cold etc etc...

[engelmohr2006]

incredible and this is what manipulates and controls our weather climate system awesome

[ברוך כהן]

8989894712850 שערי עולם

[Llathrum Marine Mechanic]

Actually I saw a video concerning a small puddle of super heavy salt water, that even lapped against some algae like a tiny ocean.

[southwestsearch]

It amaze's me of the diversity of these comments. Maybe true but then maybe not. Scholar's have been wrong before and scientists, well, who knows for sure? Scholar's, " the earth is flat ", " the sun revolves around the earth ". Cold salinity is dense therefore is at the bottom of the ocean. The Titanic looks in pretty good shape with all that salt to corrode it.

[kangphil]

Not entirely, there are many other variables than can manipulate the climate. Though it does explain in large part the long periods of stability in the global climate system.

[kangphil]

None of the circulation is 'visible', and is slower at depth because of friction with the ocean floor. Remember it takes any one water molecule ~1,000 years to go through the entire Thermohaline Circulation.

[jets8029]

I feel like I'm in 5th grade sex ed

[wikieditspam]

I've heard that if a significant amount of arctic ice melts or drifts south into the North Atlantic it could disrupt the current that supplies the right amount of warm water to the American north east and the coast of Europe giving them a temporary but disastrous cooling down. Also disruption of this current supposedly will create more frequent and more devastating storms moving further north with more power ever observed.

[keyshawn dick]

amazing animation of the underwater suface

[Jkizzle4996]

does anyone else think this looks like sperm?