Researchers have recently discovered a gigantic freshwater reservoir hidden beneath the Atlantic Ocean off the northeastern coast of the United States. The details of the study are published in Scientific Reports.
This is not the first time we hear about this aquifer. Already in the 1970s, oil companies operating off Massachusetts and New Jersey had already spotted “pockets” of freshwater here and there. But it was thought at the time that these reserves were scattered, without much interest. Since then, the instruments allowing the detection of these aquifers have been perfected. A few years ago, Kerry Key, from Columbia University in New York, began surveying the seabed identified in the 1970s. The data then revealed a gigantic reservoir of fresh, slightly salty water.
For this study, the researcher relied on an electromagnetic imaging technique. Like X-rays that allow doctors to visualize a person’s bones, electromagnetic imaging uses waves to detect hidden objects underground. Since salt water conducts electromagnetic waves better than fresh water, low conductance can identify an aquifer. After a dozen days at sea, Kerry Key and his team noted that there was indeed fresh water, but that the reservoir was continuous.
Its exact size is not yet known, but initial analyzes suggest that the aquifer could cover an area of 350 km2 and contain up to 2,800 cubic kilometers of water. This huge “pocket” of water would be buried about 182 meters below the ocean floor, and sink up to 1,000 meters deep.
For the researchers, this water could also be quite old, and date from the last ice age. 15,000 years ago, as temperatures melted glaciers, some of the water became trapped beneath the sediment. This fact also highlights the slight salinity of this water. The outer edges of the reservoir appear to be the saltiest (about 15 parts per thousand, compared with 35 parts per thousand for typical seawater). This suggests that this freshwater has been slowly mixing with seawater for thousands of years. There must be a connection. In other words, the aquifer is not stagnant.
This new discovery is therefore excellent news. The fact that it is low in salt suggests that its treatment could be easy (and cheaper) than classic saltwater. Freshwater is an increasingly rare commodity on Earth. For several decades, urbanization and global warming have reduced resources around the globe. A real water stress threatening the survival of millions of people. An additional reservoir will not do harm.