July 18, 2019

Fresh Water Under The Sea

2 minutes

A new survey of the sub-seafloor off the U.S. Northeast coast has revealed the existence of a gigantic aquifer of relatively fresh water trapped in porous sediments lying beneath the salty ocean. This appears to be the largest such formation ever found.

The newly-discovered aquifer stretches from the shore at least from

Massachusetts to New Jersey and extends more-or-less continuously out about 50

miles to the edge of the continental shelf.

The deposits begin at around 600 feet below the ocean floor and bottom

out at about 1,200 feet. If all that

water was found on the surface, it could create a lake some 15,000 miles in

area. The researchers estimate that the

region holds at least 670 cubic miles of fresh water.

Researchers made use of innovative measurements of electromagnetic

waves to map the water, which had not been detected by other technologies. It was already known that fresh water

existed in places under the sea bottom as a result of oil drilling as far back

as the 1970s. But there was previously no

hint of the extent of the undersea aquifer.

The water probably was trapped by sediments deposited during the last

ice age when sea levels were much lower.

But modern subterranean runoff from land sources might also be a

contributor.

If water from the aquifer was to be withdrawn, it would still have to be desalinated for most uses, but the cost would be much less than processing ordinary seawater. There is probably no need to do this in the Northeastern US, but the discovery suggests that such aquifers probably lie off many other coasts worldwide and could provide desperately needed water in places like southern California, Australia, the Mideast or Saharan Africa.

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Scientists Map Huge Undersea Fresh-Water Aquifer Off U.S. Northeast

Photo, courtesy of August 1, 2015, courtesy of Michael Vadon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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