A vast body of low salinity water is hiding beneath the Atlantic seafloor off the United States, a relic of ancient ice age landscapes that now sits under salt water. Scientists say this “secret” aquifer may be around 20,000 years old and so voluminous that, if tapped carefully, it could meet the needs of a metropolis the size of New York City for centuries.
What sounds like science fiction is instead the product of painstaking geophysics, offshore drilling and chemical analysis, revealing a freshwater system that stretches from New Jersey toward New England and potentially far beyond. I see it as one of the most striking examples of how rethinking where we look for water could reshape the politics and engineering of life along the East Coast.
How a hidden aquifer off the East Coast came into focus
The basic picture is deceptively simple: beneath the Atlantic seabed off the East Coast, scientists have mapped a giant lens of low salinity groundwater trapped in the sediments that fringe the continental shelf. Earlier work along the U.S. Northeast used a marine electromagnetic survey to show that this body of water extends for tens of miles offshore and covers roughly 15,000 square miles, a footprint comparable to a small inland sea. More recent drilling has confirmed that the water is fresh to slightly brackish, not the full strength seawater that surrounds it, and that it is stored in porous sands and gravels laid down when sea level was far lower.
The scale of the discovery became clearer when researchers quantified the volume. One detailed analysis of the aquifer off the Jersey Shore estimated that it holds about 2,800 cubic kilometers of water, or roughly 670 cubic miles, and that the freshwater zone stretches about 56 miles offshore. That work tied the origin of the aquifer to the Last Glacial Maximum, when sea level was lower and rivers flowed across what is now the continental shelf, recharging sediments with fresh water that later became sealed beneath rising seas.
From Liftboat Robert to Expedition 501: drilling into “secret” water
Turning a geophysical anomaly into a confirmed freshwater resource required drilling through the seabed, a task that has unfolded in stages. In one high profile campaign, scientists spent months working from Liftboat Robert, a specialized vessel that can jack itself above the waves to provide a stable drilling platform in the North Atlantic. That offshore push, summed up by the tongue in cheek mantra “Drill, baby, drill. For water,” produced cores and fluid samples that showed the undersea aquifer was not only extensive but also fresh enough to be treated for drinking, with scientists confirming that the water was safe to drink and use after appropriate processing…