New Water Source: Under the Sea?

Under trillions of tons of water might not be the most obvious place to look for ... more water, but that's where scientists have found vast reserves of freshwater that could sustain future generations as aquifers run dry. Water resources under seabeds were once thought to be rare, but researchers now believe around 500,000 cubic kilometers of fresh or brackish water can be found off the coasts of Australia, China, North America, and South Africa, enough to greatly reduce the impact of future droughts and water shortages, ScienceAlert reports.

The deposits were formed hundreds of thousands of years ago, when rain filled up water tables under areas that became ocean as sea levels rose. "The volume of this water resource is a hundred times greater than the amount we’ve extracted from the Earth’s sub-surface in the past century since 1900," the lead researcher of a study published in Nature says. "Knowing about these reserves is great news because this volume of water could sustain some regions for decades." He warns, however, that activities like drilling for oil can contaminate the reserves—and when they're gone, they "won’t be replenished until the sea level drops again, which is not likely to happen for a very long time." (A similarly fascinating recent find: an ancient ocean underneath the Chesapeake Bay.)