July 1 2019 08:23 AM

The aquifer spans 15,000 square miles stretching from New Jersey to Massachusetts.

Scientists have identified a huge reservoir of relatively fresh water off the east coast of the United States (marked with yellow hatches). Solid yellow or white lines with triangles show ship tracks.
Photo courtesy of NBC News

A vast reservoir of relatively fresh water has been discovered locked within layers of porous rock beneath the Atlantic Ocean off the east coast of the U.S., according to an article by NBC News.

The newfound aquifer spans about 15,000 square miles, stretching from New Jersey out beyond Martha’s Vineyard, and is thought to hold about 670 cubic miles of brackish water. That’s equivalent to more than half the total volume of Lake Michigan, according to Chloe Gustafson, a doctoral student at Columbia University’s Lamont-Doherty Earth Observatory and the leader of the survey that revealed the aquifer.

Gustafson says it’s important to remember that these aren’t open caverns or lakes underneath the seafloor. This water is trapped within the pores of rocks similar to a water-soaked sponge. She says scientists had known since the 1970s that a vast formation like the one the researchers found could exist off the east coast after companies drilling for offshore oil found evidence of freshwater deposits nearby. But the new survey is the first to establish the aquifer’s size and map it in detail.

The newfound aquifer and others like it could represent an important resource, especially for water-starved regions, says Andrew Fisher, a professor of physical and biological sciences at the University of California, Santa Cruz. Extracting the water locked in the rock layers and treating it to make it potable would likely be costly and possibly impractical, Fisher says. But he adds that it might be a reasonable option in parts of the world facing crippling water shortages.

Others doubt the long-term feasibility of tapping subsea reservoirs. According to Graham Fogg, a professor of hydrogeology at the University of California, Davis, there’s a limit to how much you can pump sustainably. He says that while it would take a long time to empty these aquifers, it would be possible to pump too much and exhaust the supply.