The earth’s oceans are always in motion, and while tides and currents crash against the
coasts, huge cataracts fall for miles within the deep waterfalls on the surface. Seven
major cataracts have been found deep below the ocean surface. Most are caused by
temperature differences between separate ocean basins. For instance, heavy, cold water
at the North and South Poles sinks to the seafloor, where it sweeps along the undersea
terrain. It flows downhill, deeper and deeper, until the river finally plunges over into
an adjacent ocean basin.
The largest cataract exists beneath the Denmark Strait between Greenland and Iceland.
This underwater waterfall drops nearly 11,500 feet, more than three times Venezuela’s
Angel Falls, the earth’s highest waterfall at 3,212 feet. The submarine waterfall carries
at least 175 million cubic feet of water per second, making it 350 times as voluminous as
Guaira Falls on the border of Brazil and Paraguay which was once considered to carry more
water than any other waterfall on the earth’s surface.