Invisible to us terrestrial creatures, an underwater present circles the globe with a pressure 16 instances as sturdy as all of the world’s rivers mixed [source: NOAA: “Ocean”]. This deep-water present is named the international conveyor belt and is pushed by density variations within the water. Water actions pushed by variations in density are also referred to as thermohaline circulation as a result of water density depends upon its temperature (thermo) and salinity (haline).
Density refers to an object’s mass per unit quantity, or how compact it’s. A heavy, compact bowling ball is clearly going to be denser than an air-filled seaside ball. With water, colder and saltier equals denser.
At the earth’s poles, when water freezes, the salt doesn’t necessarily freeze with it, so a large volume of dense cold, salt water is left behind. When this dense water sinks to the ocean floor, more water moves in to replace it, creating a current. The new water also gets cold and sinks, continuing the cycle. Incredibly, this process drives a current of water around the globe.
The global conveyor belt begins with the cold water near the North Pole and heads south between South America and Africa toward Antarctica, partly directed by the landmasses it encounters. In Antarctica, it gets recharged with more cold water and then splits in two directions — one section heads to the Indian Ocean and the other to the Pacific Ocean. As the two sections near the equator, they warm up and rise to the surface in what you may remember as upwelling. When they can’t go any farther, the two sections loop back to the South Atlantic Ocean and finally back to the North Atlantic Ocean, where the cycle starts again.
The global conveyor belt moves much more slowly than surface currents — a few centimeters per second, compared to tens or hundreds of centimeters per second. Scientists estimate that it takes one section of the belt 1,000 years to complete one full circuit of the globe. However slow it is, though, it moves a vast amount of water — more than 100 times the flow of the Amazon River. [source: NOAA: “Currents”].
The worldwide conveyor belt is essential to the bottom of the world’s meals chain. Because it transports water across the globe, it enriches carbon dioxide-poor, nutrient-depleted floor waters by carrying them by means of the ocean’s deeper layers the place these components are ample. The vitamins and carbon dioxide from the underside layers which can be distributed by means of the higher layers allow the expansion of algae and seaweed that finally help all types of life. The belt additionally helps to control temperatures.
Learn on to find out about a present that is not attributable to winds or density variations however by forces which can be out of this world.