Here’s a news item that illustrates how truly little we know about the world’s oceans. British scientists, using deep-water submersible robots in the Black Sea, have discovered what is, in essence, the world’s sixth-largest river – at the bottom of the sea.
From this story in the (UK) Telegraph:
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 undersea river, which is up to 115ft deep in places, even has rapids and waterfalls much like its terrestrial equivalents.
If found on land, scientists estimate it would be the world’s sixth largest river in terms of the amount of water flowing through it. The discovery could help explain how life manages to survive in the deep ocean far out to sea away from the nutrient rich waters that are found close to land, as the rivers carry sediment and nutrients with them.
The scientists, based at the University of Leeds, used a robotic submarine to study for the first time a deep channel that had been found on the sea bed. They 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. Dr 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.”