The oceans live by their own rules, which are in harmony with the laws of the universe. For a long time, people have noticed that water masses are actively moving, but they could not understand what these fluctuations in sea level are connected with. Let's find out what is high tide, low tide?
Ebb and flow: mysteries of the ocean
Sailors knew very well that the tides were ebbs and flows every day. But neither ordinary inhabitants nor learned minds could understand the nature of these changes. As early as the fifth century BC, philosophers tried to describe and characterize how the oceans move. The ebb and flow of the tides seemed to be something fantastic and unusual. Even reputable scientists considered the tides to be the breath of the planet. This version has existed for several millennia. Only at the end of the seventeenth century, the meaning of the word "tide" was associated with the movement of the moon. But it has not been possible to explain this process from a scientific point of view. Hundreds of years later, scientists figured out this mystery and gave an exact definition of the daily change in water level. The science of oceanology, which emerged in the twentieth century, established thattide is the rise and fall of the water level of the oceans due to the gravitational influence of the moon.
Are the tides the same everywhere?
The influence of the moon on the earth's crust is not the same, so it cannot be said that the tides are identical all over the world. In some parts of the world, daily sea level drops reach up to sixteen meters. And the inhabitants of the Black Sea coast almost do not notice the ebb and flow, as they are the most insignificant in the world.
Usually the water level changes twice a day - in the morning and in the evening. But in the South China Sea, the tide is the movement of water masses, which occurs only once every twenty-four hours. Most of all, changes in sea level are noticeable in straits or other bottlenecks. If you observe, then with the naked eye it will be noticeable how quickly the water leaves or comes. Sometimes in a few minutes she rises to five meters.
What causes the tides to ebb and flow?
As we have already found out, the change in sea level is caused by the impact on the earth's crust of its invariable satellite of the Moon. But how does this process take place? To understand what a tide is, it is necessary to understand in detail the interaction of all the planets in the solar system.
Moon and Earth are in constant dependence on each other. The Earth attracts its satellite, and that, in turn, tends to attract our planet. This endless rivalry allows you to maintain the required distance between the two cosmic bodies. The moon and earth move in their orbitsmoving away, then approaching each other.
At the moment when the Moon comes closer to our planet, the earth's crust arches towards it. This causes a wave of water on the surface of the earth's crust, as if it tends to rise higher. The separation of the earth's satellite causes a drop in the level of the World Ocean.
Tide interval on Earth
Since the tide is a regular phenomenon, it must have its own specific interval of movement. Oceanologists have been able to calculate the exact time of the lunar day. This term is usually called the revolution of the moon around our planet, it is slightly longer than our usual twenty-four hours. Every day the tides shift by fifty minutes. This time period is necessary for the wave to "catch up" with the Moon, which moves thirteen degrees per Earth day.
Influence of ocean tides on rivers
What is the tide, we have already figured out, but few people know about the impact of these ocean fluctuations on our planet. Surprisingly, even rivers are affected by ocean tides, and sometimes the result of this intervention is incredibly frightening.
During high tides, a wave that enters the mouth of a river meets a stream of fresh water. As a result of the mixing of water masses of different densities, a powerful shaft is formed, which begins to move at great speed against the flow of the river. This stream is called boron, and it is capable of destroying almost all living things in its path. A similar phenomenon in a few minuteswashes away coastal settlements and erodes coastlines. Bor stops as suddenly as it started.
Scientists have recorded cases when a powerful boron turned rivers back or completely stopped them. It is not hard to imagine how catastrophic these phenomenal tidal events have become for all the inhabitants of the river.
How do tides affect marine life?
No wonder the tides have a huge impact on all organisms that live in the depths of the ocean. The hardest part is for small animals that live in coastal zones. They have to constantly adapt to changing water levels. For many of them, tides are a way to change habitat. During high tides, small crustaceans move closer to the shore and find food for themselves, the ebb wave pulls them deeper into the ocean.
Oceanologists have proven that many marine life is closely related to tidal waves. For example, in some species of whales, metabolism slows down during low tides. In other deep-sea inhabitants, reproductive activity depends on the height of the wave and its amplitude.
Most scientists believe that the disappearance of phenomena such as fluctuations in the level of the oceans will lead to the extinction of many living beings. Indeed, in this case, they will lose their source of nutrition and will not be able to adjust their biological clock to a certain rhythm.
The speed of the Earth's rotation: is the influence of the tides great?
For many decades, scientists have been studying everything related to the term "tide". This is the onea process that every year brings more and more mysteries. Many experts attribute the speed of the Earth's rotation to the action of tidal waves. According to this theory, sea currents are formed under the influence of tides. On their way, they constantly overcome the resistance of the earth's crust. As a result, almost imperceptibly for humans, the speed of the planet's rotation slows down.
Studying sea corals, oceanologists found out that a few billion years ago, the earth's day was twenty-two hours. In the future, the rotation of the Earth will slow down even more, and at some point it will simply equal the amplitude of the lunar day. In this case, as scientists predict, the ebbs and flows will simply disappear.
Human activity and the amplitude of fluctuations in the World Ocean
It's not surprising that humans are also affected by the tides. After all, it is 80% liquid and cannot but respond to the influence of the moon. But man would not be the crowning achievement of nature if he had not learned to use almost all natural phenomena to his advantage.
The energy of the tidal wave is incredibly high, so for many years various projects have been created to build power plants in areas with a large amplitude of water movement. There are already several such power plants in Russia. The first was built in the White Sea and was an experimental version. The power of this station did not exceed eight hundred kilowatts. Now that figure seems ridiculous, and new tidal wave power plants are generating power to power many cities.
Scientists see these projects as the future of Russian energy, because tidal power plants make it possible to take care of nature and cooperate with it.
Ebb and flow are natural phenomena that were not studied at all not so long ago. Each new discovery by oceanologists leads to even greater questions in this area. But perhaps someday scientists will be able to unravel all the mysteries that the ocean tide presents to mankind every day.
