Rivers in the ocean

It is known that there are giant jet streams in the ocean, which determine the climate of many countries. For example, the Gulf Stream and Oyashio spread over thousands of kilometers, the Gulf Stream pumps huge masses of warm water from tropical latitudes to the polar regions every year. Oyashio, on the other hand, drives chilled waters in high latitudes along the ridge of the Kuril and Japanese islands to the south. Not so long ago, other currents, no less powerful, were discovered in the ocean. These are the so-called rivers in the ocean. They flow near the bottom surface above the foot of the continental slopes from high latitudes to low latitudes. Since these currents carry their waters along the contour of the continents, they are called contour geostrophic.

Not so long ago, other currents, no less powerful, were discovered in the ocean. These are the so-called rivers in the ocean

The first evidence of the existence of these rivers in the ocean was photographs of areas of the bottom at depths of 3000–5000 m, taken in the southern regions of the Atlantic outskirts of the United States. They clearly show various signs of ripples on the surface of the sediment. Ripple marks are a system of sub-parallel underwater shafts and troughs separating them, which resembles a wind ripple that occurs on the surface of the water. Its appearance at the bottom is associated with the redistribution of sediment particles under the influence of the jets of the bottom current. Ripple marks are known in river beds, in deltas, on tidal plains, on open shelf areas - in a word, wherever water masses move. Small ripples, mega-ripples and underwater dunes are distinguished depending on the height of the crests of the underwater shafts and the distances between them. Mega-ripples, for example, are characterized by the excess of its crests over the bed of troughs not exceeding 60 cm and the distance between adjacent ripple waves up to 12 m. Similar "waves", but of lesser height and length, are referred to simply as ripple signs. Finally, large accumulative bodies on the bottom surface, in association with coastal fill forms, are called underwater dunes.

In deep-water environments, rivers in the ocean formed dunes with a height of 91 m. Often they line up in chains with a distance of 9,6 km between adjacent embankments. Within the continental foothills, whole fields of ripples were discovered that formed on the surface of the sediment. It became clear that this was a new phenomenon. Further investigations confirmed that traces of global-scale processes were found that play a primary role in the "ventilation" (ventilation) of the ocean depths. Current velocity sensors installed at the bottom recorded steady movements of water masses over some of its sections at a speed of up to 50 cm/s. These bottom currents rushed to the equator and, as it turned out soon, even crossed it, penetrating into the other hemisphere. First, the Arctic contour current was discovered, formed by the cold waters of the high latitudes of the northern hemisphere. Then, over the continental foot of South America in the Atlantic Ocean, another contour current was discovered, carrying cold waters of Antarctic origin to the equator. Over the outskirts of southern Brazil, both currents meet and flow one under the other in opposite directions: the arctic water masses over the Antarctic, colder and heavier.

Like rivers on land, rivers in the ocean move not only huge bodies of water, but also significant amounts of sedimentary material. At a speed of 40-50 cm/s, water is capable of dragging rather large particles, up to coarse sand. Strictly speaking, the ripple marks are direct evidence of the movement of precipitation. After all, ripple waves constantly migrate, moving along the course of the current with a small, but fairly constant speed. The efficiency of this process is evidenced by the fact that sedimentary material, picked up in high arctic latitudes, eventually ends up near the equator and even to the south of it. Moreover, contour currents, or rivers in the ocean, whose energy is largely consumed on the way to the equator, are no longer able to move a significant number of particles over a certain segment. They settle to form fields of underwater dunes or gigantic embankments. One of the most studied formations of this kind is the Blake Wall. The length of the other wall, the Newfoundland one, exceeds 500 km, and the height is more than 1 km.