Our Planet Is Eating its Own Oceans

Earth’s Hidden Water: Tectonic Plates Swallow More Ocean Than Previously Thought

The Mysterious Disappearance of Seawater

According to recent research, Earth’s crust is absorbing more ocean water than previously believed. Seawater appears to be “disappearing” into trenches created by the movement of interlocking tectonic plates. As these plates shift, they pull more water into the Earth than previously estimated, says a new study from specialists at Washington University, published in the journal Nature.

Underwater Seismic Sensors Reveal New Findings

Scientists led by Chen Cai used data collected by various seismic sensors installed 11,000 meters beneath the sea in the Mariana Trench, the deepest part of Earth’s oceans. “Before we did this study, every researcher knew that water must be carried down by the subducting slab,” Cai told Live Science. “But they just didn’t know how much water.”

In the Western Pacific, these devices detected earthquakes and their echoes, which travel along the Earth’s crust. Cai and his team measured the speed of these tremors, with deceleration indicating the presence of water in rock fractures and water-containing mineral crystals.

Unprecedented Amounts of Water Absorbed by Earth’s Crust

After recording echo deceleration and considering factors like temperature and pressure, scientists calculated that 3,000 million teragrams of water are lost in the crust and mantle every year. Seawater is heavy; a cubic meter of water weighs 1,024 kilograms (2,250 lbs.). However, the amount pulled down by subduction zones is staggering, three times more than previous estimates, according to Cai.

Imbalance in Earth’s Water Cycle

Water absorbed by the Earth’s crust should reappear on the surface, typically through volcanic eruptions. However, recent estimates from the Washington University study reveal a significant imbalance between the amount of water taken in and the amount released. Cai notes that this disparity implies that “scientists still do not understand the way water moves inside the Earth.” Further research is needed to unravel the mysteries of Earth’s water cycle and the movement of water within our planet’s crust and mantle.