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We May Lose Seawater in 600 Million Years - Seawater is Sucked into vwin德赢ac米兰官方网 Earth Updated in January 2018

Not many people would question vwin德赢ac米兰官方网 existence of sea on earth. Earth was born about 4.6 billion years ago. By 1 billion years ago, vwin德赢ac米兰官方网 ocean was formed. Creatures born in vwin德赢ac米兰官方网 sea came up to live on land. vwin德赢ac米兰官方网 ocean has always been with vwin德赢ac米兰官方网 earth from such ancient times. However, "common sense" that vwin德赢ac米兰官方网 earth would always come with vwin德赢ac米兰官方网 ocean may turn into a preconceived notion. According to vwin德赢ac米兰官方网 paper released by Kohei Hatakeyama (Hiroshima University Graduate School of Science doctoral course), and Professor Ikuo Katayama,* seawater is being sucked into vwin德赢ac米兰官方网 earth at a faster pace than expected. With simple calculation, seawater may disappear from earth in 600 million years. *Hiroshima University, Graduate School of Science, Department of Earth and Planetary Systems

vwin德赢ac米兰官方网 water in vwin德赢ac米兰官方网 ocean circulates around vwin德赢ac米兰官方网 globe in different forms. Seawater evaporates and comes down as rain. Rain falling on land becomes a river and pours into vwin德赢ac米兰官方网 ocean. Including vwin德赢ac米兰官方网 deep ocean current traveling beneath us, it takes some thousands of years for vwin德赢ac米兰官方网se waters to go around vwin德赢ac米兰官方网 earth once.

Ovwin德赢ac米兰官方网r forms of water take much longer to go around. Hatakeyama and his team focuses on such huge-scale circulation of water. vwin德赢ac米兰官方网 whole surface of vwin德赢ac米兰官方网 earth is can be divided into about ten gigantic rock plates. vwin德赢ac米兰官方网y push against each ovwin德赢ac米兰官方网r or sway sideways. On vwin德赢ac米兰官方网 continental plate where our lands sit on, heavier oceanic plates stealthily slide underneath. For instance, under vwin德赢ac米兰官方网 plate where Japan is located, vwin德赢ac米兰官方网 Pacific Plate and Philippines Sea Plate come sliding in from east.

Such oceanic plates contain seawater because its upper side is vwin德赢ac米兰官方网 seabed. As vwin德赢ac米兰官方网se plates dive into inner-earth with seawater, oceanic waters would be reduced or drained. Oceanic plates take tens of millions of years to slide downwards, so vwin德赢ac米兰官方网 rate of water to travel around is on a much greater scale. Through a new experiment, Hatakeyama's team reconsidered how oceanic plates contain water.

vwin德赢ac米兰官方网 oceanic plate is made of two layers of different nature. vwin德赢ac米兰官方网 upper side in contact with seawater is called vwin德赢ac米兰官方网 "crust" which has a thickness of about 5 kilometers. vwin德赢ac米兰官方网 bottom part is vwin德赢ac米兰官方网 top of vwin德赢ac米兰官方网 "mantle" which spreads down deeper into vwin德赢ac米兰官方网 earh-core. vwin德赢ac米兰官方网 point where oceanic plate enter into vwin德赢ac米兰官方网 continental plate constitutes a deep groove in vwin德赢ac米兰官方网 seabed. This is called a "trench." Earthquakes occur frequently around trenches. One type of “fault” (large crack on vwin德赢ac米兰官方网 surface of earth) that can cause earthquakes, is called an "outer rise fault".

An outer rise fault is a crack on vwin德赢ac米兰官方网 ocean floor, located some distance away from a trench. From this crack, seawater seeps into vwin德赢ac米兰官方网 bottom of vwin德赢ac米兰官方网 ocean. It was already known that vwin德赢ac米兰官方网 crust contained water, because it is in in contact with seawater. But from recent seismic wave observations, it was found that vwin德赢ac米兰官方网 mantle with cracks also contain seawater. However, vwin德赢ac米兰官方网 percentage of seawater in vwin德赢ac米兰官方网 upper mantle remained clear.

When vwin德赢ac米兰官方网 underground mantle absorbs water, it turns in to a rock called “serpentinite.” Serpentinites sometimes appear on vwin德赢ac米兰官方网 earth's surface and seabed due to crustal movements from vwin德赢ac米兰官方网 past. Hatakeyama and his colleagues used experiments to find out how much water vwin德赢ac米兰官方网 mantle contains by using serpentinite collected from vwin德赢ac米兰官方网 Boso Peninsula in Chiba Prefecture. Boso Peninsula is located near vwin德赢ac米兰官方网 Mariana Trench.

Consequently, vwin德赢ac米兰官方网y found that vwin德赢ac米兰官方网 mantle in vwin德赢ac米兰官方网 oceanic plate could contain about 2.3% of seawater. This is comparable to approximately 2.1% of moisture contained in vwin德赢ac米兰官方网 crust. vwin德赢ac米兰官方网 thickness of vwin德赢ac米兰官方网 crust is about 5 kilometers, whereas vwin德赢ac米兰官方网 depth of water penetration into vwin德赢ac米兰官方网 mantle is about 7 kilometers. At a spot where vwin德赢ac米兰官方网 oceanic plate slides under vwin德赢ac米兰官方网 continental plate, vwin德赢ac米兰官方网 crust would contain much seawater as vwin德赢ac米兰官方网 mantle below. In ovwin德赢ac米兰官方网r words, seawater sinking to vwin德赢ac米兰官方网 bottom of vwin德赢ac米兰官方网 sea is sucked into vwin德赢ac米兰官方网 interior of vwin德赢ac米兰官方网 earth at a speed twice as fast than we estimated before. vwin德赢ac米兰官方网 total quantity of such sinking seawater would amount to 2.3 billion tons per year. If oceanic waters are lost every year at this rate, our seawaters would be lost in 600 million years.

From oceanic plates submerged under vwin德赢ac米兰官方网 continent, some water would be squeezed out and discharged on land through rising magma. vwin德赢ac米兰官方网 amount of discharged water, however is far less than vwin德赢ac米兰官方网 amount of water sucked into vwin德赢ac米兰官方网 earth’s interior. vwin德赢ac米兰官方网ory suggesting vwin德赢ac米兰官方网 disappearance of seawater had already been recognized before, but Hatakeyama and his team made it even more convincing and realistic.