A freshwater sea under the salty ocean: it seems a paradox but it is reality. A research team has discovered a gigantic aquifer of freshwater trapped in porous sediments that lie beneath the immense expanse of water from Massachusetts to New Jersey. It could be a reserve for the arid regions of the world.
He is about to end up run over, his mother saves him
A freshwater sea under the salty ocean: it seems a paradox but it is reality. A research team from Columbia University has discovered a gigantic aquifer of freshwater trapped in porous sediments that lie beneath the vast expanse from Massachusetts to New Jersey. It could be a reserve for the arid regions of the world.
A lake that covers approx 25 thousand square kilometers if found on the surface, larger than Balkhash, the largest in Central Asia: these are the dimensions of the incredibly huge discovered aquifer.
And it doesn't stop there, because the study suggests such aquifers could be found on many other coasts around the world (searches of this type, on the other hand, had already been carried out), constituting potential water basins for the areas where it is desperately needed. Far from "just" a scientific curiosity, then.
"We knew there was fresh water in isolated places, but we didn't know its extent or geometry - explains Chloe Gustafson, lead author of the research - Could prove to be an important resource for other parts of the world ”.
The first signs of this effect date back to the 70s and, for once, it was there search for oil to be useful: the oil companies, in fact, in their underwater search for hydrocarbons, sometimes found fresh water and scientists have long debated whether the water deposits were only isolated basins or extensions of quite another dimension. The holes made for oil exploration are in fact very limited in diameter.
But 20 years ago Kerry Key, co-author of this study and who had helped oil companies develop research techniques in the seabed, decided to test whether these could also be used to find freshwater deposits, and in 2015 they were made targeted studies in this regard.
Multi-point analyzes have shown that the deposits are not scattered but continuous, starting at the shoreline and extending far into the shallow continental shelf, sometimes up to 120 kilometers. In most cases they start at a depth of about 180 meters and reach 360.
Photo: Columbia University
But why is there fresh water under salt water? According to the most accredited hypotheses, about 15.000-20.000 years ago, towards the end of the last ice age, much of the planet's water was enclosed in an ice 1,5 kilometers deep and sea levels were much lower. But as the ice melted, fresh water was trapped there, even as sea levels rose. Until now, the capture of such "fossil" water has been the most "certain" explanation.
According to the Columbia University research team, however, this particular aquifer could also be fed by the modern underground runoff from the earth, as happens to the rains that percolate through the terrestrial sediments.
However, the aquifer is generally softer near shore and saltier at a distance, suggesting that it gradually mixes with ocean water over time. Therefore, to be used as fresh water, it would still have to be desalinated, albeit with a less demanding process (even economically).
"We probably don't need to do that in this region, but we can show that there are large aquifers in other regions, which could potentially be a resource," says Sure Key, who promises to carry out similar surveys elsewhere. "The water resources of our planet are in fact running out and we terribly need water ".
The work was published on Scientific Reports.
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- Humans are causing the biggest hydrological shift ever, according to NASA
Roberta de carolis
Cover: Rafael Marchante/Reuters via Wordl Economic Forum
