Captain Da Shanzhaowan's Notes | Deep Sea Part 1

Big Sea

The earth is the mother of mankind. She nurtures life with water, so seven-tenths of the earth's surface is sea.

Although this planet that gave birth to us is called "Earth", it is actually a water ball.

The land is like the younger brother of the ocean, trapped in the embrace of 361 million square kilometers.

The land of the past was a land, and the ocean of the past was also an ocean. However, everything is moving and will not stay in the past.

In the movement of the earth's crust, the land split and the oceans separated, and there were inner oceans and outer oceans. The outer ocean is the Pacific Ocean, which is a descendant of the former super ocean; the Atlantic Ocean, Indian Ocean, Southern Ocean, Arctic Ocean, these oceans that appeared due to the movement of the earth's crust are called inner oceans.

How deep is the ocean? How deep is the ocean? This is a question that humans have been pursuing.

When Magellan sailed around the world, he tied a 731-meter-long rope to a cannon shell and threw it into the sea. When it did not touch the bottom, he felt that the deep sea had no bottom.

In the 19th century, people still used ropes with weights hanging on them to measure depth, but the ropes were upgraded to piano wire, which could touch the bottom, sink faster, and be more accurate.

By the beginning of the 20th century, acoustic wave detection technology had truly improved the time and accuracy of depth detection, making it possible to measure data at a depth of 10,000 meters in just a dozen seconds.

Today, we are able to use satellite remote sensing technology to measure the seabed topography, and depth is no longer a problem.

The secret of undercurrents In the vast water world, there are not only surface currents that move with the wind, but also deep currents that change secretly. The so-called ocean conveyor belt originates from the power of these undercurrents. The center of power is in the Southern Ocean, where there is the Antarctic westerly belt, where the wind is strong and can stir up the water in the deep ocean.

Cold water flows up and warm water flows down. This inversion starts from the Southern Ocean and affects the changes in global ocean currents. It not only controls the global carbon cycle, but also affects climate change. Therefore, oceanography regards the Southern Ocean as the center of the world's oceans.

The ocean conveyor belt is the overturning flow path formed by the entire energy transfer process, which rises from the Southern Ocean and descends to the northern Atlantic Ocean.

The British warship, a salvage science vessel, was temporarily ordered to transform into the Challenger research vessel, which crossed the three oceans in a thousand days and brought back unprecedented research materials.

This was a remarkable scientific expedition of the 19th century, with a route length equivalent to three times around the earth. Its research materials were analyzed over twenty-three years and brought countless important scientific knowledge: it confirmed that the water in the deep oceans is cold, that animals exist in the deepest seas, and that the Mid-Atlantic Ridge and the Mariana Trench were discovered. However, the meaning of these landforms had not yet been deciphered at the time.

Moreover, the facts brought back by the Challenger were not all correct. It also deepened people's misconception that there is no light, no life, and no movement in the deep sea. Later, scientific research found that there are storms and landslides in the deep sea, which can cut submarine cables and trigger tsunamis. This should not be underestimated.

The legend of the black chimneys on the seabed At first, people only found traces of abnormal temperature and salinity on the seabed, and boldly speculated that there were hydrothermal fluids on the seabed. Later, the discovery of metallic mud greatly excited people, and scientific research personnel became more certain about the existence of hydrothermal fluids. Submersibles from various countries began to search for needles in a haystack from the Atlantic to the Pacific.

In the vast ocean, the deep sea is vast. The solitary submersible has repeatedly searched, but only found mineral mud mounds as big as mineral water bottles in the Pacific Ocean. Fortunately, people never give up, and technology is always improving. Scientists followed the clues and used manned deep-sea diving technology to find tube worms along the shells. They followed the trail all the way and finally found dense biota. The water temperature there was as high as 17℃, and the collected water also smelled of hydrogen sulfide.

Hydrothermal fluids were discovered! At least that’s what the expeditioners thought at the time.

In the subsequent investigation, the people on the Alvin knew they were wrong. What they had discovered before was only a hydrothermal biota, because they witnessed real hydrothermal fluids at 21 degrees north latitude - two-meter-high black chimneys rising on the seabed! There, the sea water dropped and the magma surged, and the contact between the two produced metal-rich hydrothermal fluids that spewed upwards, just like black chimneys. Finally, the true face of hydrothermal fluids was finally revealed!

Attention! White chimneys and black chimneys are not the only form of hydrothermal fluids. White chimneys are equally warm and lovely. Because not only magma activity can form hydrothermal fluids, but there are other mechanisms that can also trigger hydrothermal fluid movement. At the mid-ocean ridge, residual geothermal heat can also cause chemical reactions between seawater and rocks, producing hydrothermal fluids of different temperatures.

There is a white chimney rising proudly in the Lost City. Different from the black color of metal sulfide, this is a white color made of carbonate minerals, similar to calcite, firm and not easy to collapse. It can even be as high as 10 to 20 meters, which is very magical. It is worth mentioning that the composition of the black chimney is not necessarily sulfide, but can also be minerals derived from peridotite. The deep sea is so vast that there are many possibilities worth exploring.

The fire seeds frozen on the seabed that flow out from the seabed may not necessarily be hydrothermal fluids, but may also be cold springs. The temperature of cold springs is not high and they are mainly composed of methane.

Moreover, the deep sea provides methane with the opportunity to transform into combustible ice. When it gathers, it can form both minerals and disasters.

Methane hydrate is extremely unstable. It will release gas as long as the temperature and pressure change slightly. If it releases slowly, it will become a pit on the seabed, which is called a "pit". If it erupts suddenly, it will pile up into a mountain, which is called a "mud volcano". However, no matter how fickle methane hydrate is, it is always a very popular energy source for us humans.

Cold springs are like underwater temples that preserve fire and hide incredible treasures.

The seabed is actually a door. Once upon a time, we could not touch the abyss of the ocean, so we thought it was an endless devil's land. When we entered the deep sea, we felt that it was a tangible existence after all, a resource that could be slowly mastered. But the more we study, the more we understand that the deep sea is just a barrier connecting two worlds.

Just as we may not realize, there are two water reservoirs on the earth, one is the liquid seawater on the surface, and the other is the hidden water source in the mantle. In the natural cycle, the unknown reservoir will slowly transform into visible water resources, and the deep sea is the boundary, where we can see the movement from top to bottom and also encounter the activities from bottom to top. If there is a door between the inside and outside of the earth, it may be the bottom of the deep sea.

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