Among the salty waters of the North Atlantic, geologists have discovered a huge freshwater aquifer hidden from the US coast.
The enormous size of this huge cache is surprising, but not completely unexpected. Signals of water first appeared in the 1970s, but until now no one suspected that this huge reservoir, encased in porous rock, could cover nearly the entire length of the northeastern US.
"We knew there were fresh water down there in places, but we did not know the scale or the geometry," says marine geologist Chloe Gustafson of Columbia University.
In 2015, several colleagues from Gustafson conducted a pilot study off the coast of New Jersey and the Massachusetts Island Martha's Vineyard.
Using an electromagnetic receiver deployed by the research vessel Marcus G. Langseth the team investigated groundwater deposits offshore that were buried in sediments beneath the continental shelf.
Above: Giant aquifer in yellow hatched areas with triangles representing surveying expeditions.
Oil companies had occasionally discovered freshwater as early as the 1970s when they were drilling for fossil fuels. Scientists knew there was something down there; However, data about the resource – and the size of the cache – was scarce.
To correct this, the research teams of Marcus G. Langseth studied the two locations on the northeast coast for ten days. Looking for signs of electrical conductivity in the waters below the ship.
Saltwater conducts electromagnetic waves (EM) more effectively than fresh water. Therefore, researchers with offshore EM receivers were able to grasp the scale of the puzzle of aquifers.
The results, published in a study detailing the first comprehensive attempt to map this huge reservoir, show that a largely end-by-end submarine groundwater system is at least 350 km [217 miles] The US Atlantic coast spans over and contains approximately 2,800 cubic kilometers of deep-salinity groundwater. "
However, the results are not yet clear because of the nature of EM mapping, but the team concludes that the freshwater cache of groundwater is likely to be New Jersey, New York, Connecticut, Rhode Island, and all the way to Massachusetts extend to Delaware.
As crazy as it sounds, the groundwater reservoir could expand even further, the researchers say.
"If we take the potential into account The expansion to the northeast and southwest beyond our profiles may cause the groundwater below the northeastern T of the US Atlantic continental shelf multiply and represent a freshwater resource that competes with the largest coastal aquifers, "the authors explain.
When the aquifer arrived there, researchers have probably found that large amounts of fresh meltwater from the last ice age were trapped in rocky sediments.
To use the water for drinking – if we someday decided to tap it – it would first have to be desalted, as parts of it would be brackish (especially salty), especially the parts closest to it lie The seawater periphery.
For the moment, nobody suggests that we have to do that, but the existence of the giant aquifer suggests that similar groundwater systems could easily be concealed in other hotter and drier parts of the world such as California, Australia or the US Middle East.
"It could turn out to be an important resource in other parts of the world," says Gustafson.
The results are reported in Scientific Reports .