Huge river discovered flowing on Black Sea bed

People walk at the Black Sea coast in the town of Varna east of the Bulgarian capital Sofia. File photo

A massive underwater river flowing along the bottom of the Black Sea has been found by scientists - a discovery that could help explain how life manages to survive in the deep oceans away from the nutrient-rich waters found close to land.

It is estimated that if on land, the undersea river would be the world's sixth largest in terms of the volume of water flowing through it.

Researchers working in the Black Sea have found currents of water 350 times greater than the River Thames flowing along the sea bed, carving out channels much like a river on the land, the Telegraph reports.

The undersea river, which is up to 115 feet deep in places, even has rapids and waterfalls much like its terrestrial equivalents.

The scientists, based at the University of Leeds, used a robotic submarine to study a deep channel that had been found on the sea bed, and found a river of highly salty water flowing along the deep channel at the bottom of the Black Sea, creating river banks and flood plains much like a river found on land.

Dan Parsons, from the university's School of Earth and Environment, said: “The water in the channels is denser than the surrounding seawater because it has higher salinity and is carrying so much sediment. It flows down the sea shelf and out into the abyssal plain much like a river on land. The abyssal plains of our oceans are like the deserts of the marine world, but these channels can deliver nutrients and ingredients needed for life out over these deserts.”

“This means they could be vitally important, like arteries providing life to the deep ocean. The key difference we found from terrestrial rivers was that as the flow goes round the bend, the water spirals in the opposite way to rivers on land,” Dr. Parsons said.

The undersea river discovered by Parsons and his colleagues, which is yet to be named, stems from salty water spilling through the Bosphorus Strait from the Mediterranean into the Black Sea, where the water has a lower salt content.

This causes the dense water from the Mediterranean to flow like a river along the sea bed, carving a channel with banks around 115 feet deep and 0.6 of a mile wide. It is the only active undersea river to have been found so far.