It’s easy to imagine our seas and oceans as one big pool of water, just standing there. However, this couldn’t be further from the truth. The waters of our oceans are in constant motion, driven by a whole multitude of forces. The air currents, fueled by our sun, propel the surface currents, which move warm water from the tropics towards the polar areas and are of huge importance to our delicate climate. The tides, as well as the Earth’s rotation, also play a role in their movement. But if we were to dive a little bit deeper, there are a whole different set of currents – the deep ocean currents.
These deep ocean currents are formed when waters of varying density, caused by their temperature and saltiness, meet. Because of this difference, the two bodies cannot mix, and one has to make way for the other. This process is known as thermohaline circulation and is exactly what happens at the border between Greenland and Iceland. As two seas meet, they create the biggest waterfall on Earth – the Denmark Strait cataract. 160 kilometers wide, it plunges 3.5 km straight down, carrying around 5 million cubic meters of water per second. Because a slight difference in temperature, the colder, denser and so heavier water of the Greenland Sea sinks to the bottom of the Irminger Sea, at a rate more than 2000 times larger than that of the Niagara Falls.
The subject of which land-based waterfall is the largest Is often debated, as nobody can really agree on an exact definition of what largest means. If we consider the height of the drop, then it is the Salto Ángel (Angels Falls) in Venezuela, with a total of 978 meters, falling from the summit of the Auyán-tepui. According to flow rate, it is the Inga Falls on the Kongo with 910 cu meters per second. The widest are the Khone Falls, on the border between Laos and Cambodia, spanning almost 11 kilometers.