Thousands of years ago, glaciers covered much of the planet. Oceans receded as water froze into massive sheets of ice blanketing the North American continent. As the ice age ends, glaciers melted. Massive river deltas flowed out across the continental shelf. The oceans rose, and fresh water was trapped in sediments below the waves. Discovered while drilling for oil offshore in the 1970s, scientists thought the "isolated" pockets of fresh water were a curiosity.
As reported in the latest issue (paywall) of the peer-reviewed journal Scientific Reports, scientists from Columbia University and the Woods Hole Oceanographic Institution spent 1
It turns out to be the subterranean pools stretch for at least 50 miles off the US Atlantic coast, containing vast stores of water low-salinity groundwater, about twice the volume of Lake Ontario. The deposit begins about 600 ft (183 m) below the seafloor and stretch for hundreds of miles. That rivals the size of even the largest terrestrial aquifers.
"We knew there was fresh water down there in isolated places, but we did not know the extent or geometry," said lead author Chloe Gustafson, a PhD candidate at Columbia University's Lamont-Doherty Earth Observatory, according to Phys.org. Modern-day runoff from land-and-may exist elsewhere with similar topography "
The size and extent of the freshwater deposit suggest that they are"
The water is not fresh terrestrial fresh water, which contains more than one part per thousand. Near land, the undersea aquifer has a close view to pure fresh water. Toward its edges, it may reach 15 parts per thousand (about half that of seawater). That's still valuable. Desalination plants could easily turn that into drinkable water.