The ‘sixth largest river’ on Earth is hidden 115 feet beneath the Black Sea

A remarkable geological feature was discovered beneath the Black Sea- an enormous underwater river complete with waterfalls, rapids, and floodplains. The river flows through the Bosphorus Strait and is fed by very salty and dense Mediterranean water.

According to Professor Daniel Parsons, former Lecturer at the University of Leeds and one of the researchers who made this discovery, if this river existed on land, it would be the sixth-largest river on Earth based on discharge (22,000 cubic meters per second). This ‘river within an ocean’ was found to be at least 115 feet deep and is thought to function as an important nutrient transport system for the deep sea. Advanced robotic mapping techniques verified the features of this underwater river and revealed its extensive and distinct river-like characteristics, as documented by Hydro International and the University of Leeds.

Nature and mechanism of the river that is hidden beneath the Black Sea

The river beneath the Black Sea represents an extraordinary geological occurrence and operates as a ‘river in the sea.’ While oceanic currents differ greatly from terrestrial rivers, this watercourse behaves precisely like one. The undersea river has well-defined banks, floodplains, rapids, and even undersea waterfalls. The University of Leeds' researchers found that if the undersea river were an actual river on land, its impressive 22,000 cubic meters per second flow rate would qualify it as the sixth largest in the world in terms of discharge (volume), right behind the Amazon and Yangtze rivers.

The river is driven by the dense saline current that it is made up of. The high-density saline current results from the Mediterranean Sea's salt & density water that spills through the Bosphorus Strait below the less dense & less saline Black Sea water. The dense saline water from the Mediterranean does not mix with the fresher Black Sea water and instead sinks to the seafloor, creating a channel 115 feet (35 meters) deep and 0.6 (1 kilometer) wide and travels approximately 37 miles (60 km) along the continental shelf.

Technical highlights of this river

The discovery is supported by the detailed findings of the University of Leeds and many technical publications, such as Hydro International.

Scientific importance and discovery

The abyssal plain, which is often referred to as a ‘desert’ of the ocean due to its lack of nutrients, has long been considered to be a nutrient-poor area; however, the researchers suspect that these underwater rivers may be providing the necessary oxygen and nutrients needed to support unique ecosystems that are frozen solid in the top layers of the ocean.Studying this underwater river has also provided a glimpse into the history of the Earth. Researchers believe that this underwater system started to form approximately 7,500 years ago when the Bosphorus Strait was formed and established two flow layers of water. By using the flow patterns and sediment layers, the researchers can now use this information to understand the evolution of the Black Sea basin during a time of great environmental change and rising sea levels.