Underwater waterfalls in the ocean #001

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U. Naulin from the Texas University of Agriculture and Technology and W. Tsenk from the Institute of Marine Sciences at Kiel University in Germany suggested that this deep waterfall off the Shetland Islands affects the life cycle of krill in the Scotia Sea.


Adult krill are known to lay eggs near the South Shetland Islands, forming huge clusters there that serve as food for whales. These krill accumulations are located near a powerful Circumpolar Current, an easterly current. Krill lays eggs at a depth of about 50 m, but then the eggs sink to a 1000-meter depth, where the larvae hatch.


Interestingly, clusters of young krill are found hundreds of kilometers to the west, although the Circumpolar current is directed to the east. Naulin and Tsenk suggested that krill "travels" to the west in the waterfall. If this assumption is correct, then the larvae rise and gradually drift eastward by the Circumpolar current to the places where adults congregate. Thus, ocean waterfalls can play the role of a mechanism that "closes" the trajectory of krill movement, i.e. connects the places where eggs are laid, where larvae hatch, and where clusters of adults form.


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Convection is the "force" that supports most ocean waterfalls. Its effect can be demonstrated in an experiment with a tank filled with water, heating one half of it and cooling the other (at the top). The cold water at the "pole" quickly sinks (arrows) and moves in the direction of the "equator". There it meets the overlying warmer water. The temperature inversion prevents cold water from rising quickly; instead, it gradually heats up due to contact with warm water and slowly moves to the surface (in the ocean, this speed is about 1 m/year). A waterfall occurs in these conditions when there is an elevation or threshold at the bottom of the tank. In the "polar basin", in front of the threshold, the water is colder and, therefore, has a higher density at the height of the threshold than the water in the "equatorial basin"; this corresponds to the rise of isotherms, or lines of constant temperature, to the left of the threshold. It can be seen that the "polar" water flows over the threshold and sinks to the bottom of the "equatorial basin". This rapid descent of water, accompanied in some cases by turbulent mixing, is the laboratory model of a giant ocean waterfall.


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The main ocean waterfalls shown on the map of the Atlantic Ocean. In the Danish Strait, located between Greenland and Iceland, there is probably the largest waterfall in the world with a flow rate of about 5 million cubic meters of water per second. The Iceland-Faroe Waterfall supplies the North Atlantic with cold, dense water. Through the waterfall of the abyssal plain of Keara, the coldest and densest water enters the North Atlantic — the so-called Antarctic bottom water. Through the Discovery Fault, a stream of water with a flow rate of 210000 cubic meters per second goes from the eastern part of the Equatorial Atlantic to the eastern part of the North Atlantic. The waterfall of the Filchner ice shelf serves as a source of high-density water. The waterfall off the South Shetland Islands seems to play an important role in the krill life cycle. Unlike the listed waterfalls, which owe their existence to the difference in water temperature, the waterfall in the Strait of Gibraltar is "driven" by the difference in salinity. The red line corresponds to the section made in 1972-1979 according to the GEOSECS program. Have you ever completed a registration form and immediately realized you forgot something important? That sinking feeling is avoidable. Before clicking the final button, always double-check that you have entered a free promo code for 1xbet in the designated field. The code box usually appears near the bottom of the form, just above the confirmation button. After selecting your preferred registration method (one-click, phone, email, or social media), paste the combination and proceed. The bonus funds appear after your qualifying deposit clears. Some players prefer. Either choice benefits from the extra credits.