An expedition off the coast of Massachusetts confirmed the existence of a freshwater reservoir beneath the seafloor. It could be 20,000 years old and big enough to power New York for 800 years.
A giant “secret” freshwater reservoir was discovered at the bottom of the sea, off the East Coast of the USA, which was formed during the last ice age, when the region was covered by glaciers.
The news was advanced by , who spoke with the researchers responsible for the discovery.
“It was a great project and a kind of lifelong dream,” he told the magazine. Brandon Duganexpedition leader and professor of geophysics at the Colorado School of Mines, told Live Science.
Last summer, researchers undertook an expedition to follow up on reports from the late 1960s and early 1970s that fresh water existed beneath the seafloor off the East Coast.
The research trip lasted three months and removed 50,000 liters) of water from beneath the seabed at three locations off the islands of Nantucket and Martha’s Vineyard. The results are not yet finalized, but so far it appears that the reservoir may extend further underground than early reports suggested, meaning that could be even bigger than previously thought.
Fresh water in the region was first reported 60 years ago by the United States Geological Survey (USGS) during assessments of mineral and energy resources offshore between Florida and Maine.
In 2003, Dugan and Mark Person, a professor of hydrology at the New Mexico Institute of Mining and Technology, rediscovered these records and came up with three ideas about how freshwater might end up beneath the ocean.
Dugan’s three possibilities
One way an underwater freshwater reservoir can form is if sea levels are very low for a long time and precipitation seeps into the ground. Then, when sea levels rise again over hundreds of thousands of years, this fresh water becomes trapped in the underlying sediment.
A second possibility is that high mountains close to the ocean channel rainwater directly to the seabed from their high altitude point.
Thirdly — related to the first hypothesis — a freshwater reservoir could form beneath the ocean if ice sheets expand, lowering sea levels. Meltwater accumulates at the base of ice sheets because they rub against the rocky substrate, producing heat. The enormous weight of the ice sheet then pushes this water into the ground, trapping it beneath layers of sediment.
More than two decades later, researchers are finally close to getting an answer, with preliminary data indicating that most freshwater came from glaciers sometime during the last ice age (between 2.6 million and 11,700 years ago).
“The important part of the expedition was that we collected all the samples we needed to answer our main questions”, praised Dugan.
Scientists are now studying the reservoir in greater detail, including the presence of microorganisms, rare earth elements, the pore space and the age of the sediments, which will help determine more precisely when it formed.
