By KALANI CHEN-HAYES, age 11
Northwestern University geophysicist Steve Jacobsen and University of New Mexico seismologist Brandon Schmandt recently discovered an underground water reservoir that could contain three times the amount of water in all of Earth’s oceans. The water is stored 400 miles deep in Earth’s mantle rock, and may be a part of how our planet sustains water on its surface.
The water is trapped in a layer of crystal-like minerals called ringwoodite which acts as a giant sponge. Researchers used seismometers to measure the seismic waves created by earthquakes moving through the Earth’s interior. The way the waves moved through the ringwoodite indicated that it held water. Over time and under certain conditions, the water can ooze up onto the Earth’s surface.
The discovery provides new clues in the origins of Earth’s water. Scientists previously theorized that water was formed when comets collided with Earth. It was also thought that water formed when vapor from erupting volcanoes condensed and fell as rain.
“I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet,” said Jacobsen. “Scientists have been looking for this missing deep water for decades.”
Jacobsen’s study is the first to show that ringwoodite can act as a water reservoir deep below the Earth’s surface. “We should be grateful for this deep reservoir,” says Jacobsen. “If it wasn’t there, it would be on the surface of the Earth, and mountaintops would be the only land poking out.”