The most dangerous area in the ocean absorbs 3 billion tons of water every year. Why does the sea level rise instead of falling?

The outermost layer of the Earth is a crust composed of silicate minerals, ranging in thickness from 6 kilometers on the ocean floor to 30 to 50 kilometers on land. Below the crust is the mantle, and the boundary between the mantle and the crust is the Moho discontinuity. The thickness of the mantle is about 2850 kilometers, and it is divided into the upper mantle and the lower mantle, of which there is an asthenosphere at the top of the upper mantle. Below the mantle is the core, and the boundary between the core and the mantle is the Gutenberg discontinuity. The Earth's core is divided into an outer core and an inner core. The outer core is a liquid with very low viscosity, and the inner core is a solid.

The crust and the cooler, harder upper layers of the mantle are collectively called the lithosphere, which lies above the asthenosphere.

The earth's surface (that is, the lithosphere) is composed of huge plates with a thickness of about 100-150 kilometers. The entire earth's surface can be divided into six major plates, namely the Pacific plate, the Indian Ocean plate, the Eurasian plate, the African plate, and the American plate. and the Antarctic plate.

Among them, the continental plate is relatively thick due to its low density, but relatively light. The oceanic plate is just the opposite. Due to its high density, although it is relatively thin, it is relatively heavy.

Under the action of thermal convection, the mantle composed of viscous liquid will flow, and the flow of the mantle will drive the movement of the crustal plates. The plates may squeeze and collide with each other, and may also move away from each other.

At the junction of the Eurasian plate and the Pacific plate, the flow of the mantle will cause the two to squeeze and collide with each other, but because the density of the Pacific plate is higher than that of the European plate, under the collision pressure, the edge of the Pacific plate will be downward. Subduction, so that a huge arc-shaped trench with a width of about 70 kilometers and a length of about 2550 kilometers is formed at the junction of the two, which is named the Mariana Trench.

As we all know, Mount Everest with an altitude of 8848.86 meters is the highest place on earth, known as the roof of the world. If Mount Everest is placed at the bottom of the Mariana Trench, its peak will not be above the water. In fact, the deepest point of the Mariana Trench is over 11,000 meters.

In the ocean, every 10 meters of water depth increases the pressure in the sea water by about 1 atmosphere, so the pressure at the deepest part of the Mariana Trench can reach 1,100 atmospheres. At this atmospheric pressure, each square centimeter of the area will carry a weight of 1.1 tons. In addition to the super high pressure, the bottom of the Mariana Trench is dark and there is no light at all. The average temperature here is as low as 2°C, close to freezing.

Due to the harsh environment, scientists' scientific investigation of the Mariana Trench is difficult. It was not until January 1960 that scientists successfully dived to the bottom of the Mariana Trench for the first time to conduct a field survey.

Under such harsh natural conditions, are there any creatures that survive in the Mariana Trench?

Scientists have found that within about 2,000 meters below sea level, this area is home to a variety of marine life, including common fish, shrimp, octopuses, sharks and cetaceans. Dive to a range of 2,000 to 3,000 meters, and large-mouthed anglerfish appear in this area.

From a depth of 4,000 meters, the sea water in the Mariana Trench began to become darker and darker, the pressure increased, the types of marine life began to decrease significantly, and the bones of animals began to become more and more transparent.

At the area below 8,000 meters, scientists speculate that this area should have long since become a "forbidden zone for life". However, in 2004, scientists discovered lionfish in this area, setting a new record for the depth of water inhabited by animals in the Mariana Trench. The lionfish is 25-40 cm long, with a yellow body and 13 venomous spines on its back. Its active depth is usually within 300 meters.

In 2019, the expedition team members of the China COSCO comprehensive scientific research ship "Science" discovered nearly 10 colorful coral forests on the seamounts on the south side of the Mariana Trench. In the forest, all kinds of corals and pilasters grow together, like a "undersea garden", which is really rare.

Scientists have also discovered large amounts of carbon in the Mariana Trench, which means the trench plays a far more important role in regulating the Earth's environment than previously thought. Scientists believe that the Mariana Trench is like a huge carbon dioxide collector that can continuously absorb carbon dioxide. Scientists estimate that the amount of carbon transformed by bacteria in the Mariana Trench is greater than that in the 6,000-meter-deep seafloor plain.

In 2012, Wiens, a professor of Earth and Planetary Sciences at Washington University in St. Louis, and his research team published a paper in which they studied the underwater conditions of the Mariana Trench through seafloor seismometers and hydrophones, and found that Mali. The Yana Trench is frantically swallowing seawater.

Wiens' team further estimates that the Mariana Trench swallows more than 3 billion tons of seawater each year. This means that the Mariana Trench has swallowed 3,000 trillion tons of seawater in nearly 1 million years.

Why does the Mariana Trench devour seawater like crazy?

The reason is to start with plate tectonics. When the Pacific plate is subducted and inserted into the asthenosphere, a crack or "wound" will be formed at the joint of the Eurasian plate and the Pacific plate, and seawater will flow into the ground continuously along this crack.

The Mariana Trench swallowed 3,000 trillion tons of seawater in nearly 1 million years. Why did the sea level not only not fall, but rise instead?

We've all heard of the concept of the surface water cycle, but there's actually a water cycle deep underground. Although a huge amount of seawater is sucked into the interior of the earth, this seawater is also released as water vapor by the eruption of the volcano, and then enters the atmosphere and returns to the ocean through rainfall. In addition, the seawater pouring into the earth's interior will flow back into the ocean through the outlet of hydrothermal vents. Therefore, in this continuous cycle, the sea water does not actually decrease much, and the sea level will naturally not drop.

Sea level rise is the result of climate warming. In recent decades, due to well-known reasons, global warming has intensified, and the average surface temperature has continued to rise, causing the ice sheets in the Antarctic and Arctic to gradually melt, thereby causing sea levels to rise. Scientists estimate that if all the glaciers on the earth melt, the global sea level will rise by 60-70 meters.