How did the ocean form?

The earth's surface is divided into vast waters that communicate with each other by the mainland, which is called the ocean. The total area of the earth is about 360 mill

The earth's surface is divided into vast waters that communicate with each other by the mainland, which is called the ocean. The total area of the earth is about 360 million square kilometers, accounting for 765,438+0% of the earth's surface area. But how did the ocean form? Here's what I did for you. I hope it works for you.

? Basic introduction to the ocean:

Because the ocean area of the earth is about 360 million square kilometers, which is much larger than the land area, some people call the earth a "big water polo". Traditionally, the Antarctic Sea has also been divided into three parts, belonging to three oceans. Including the corresponding part of the Antarctic Sea, the Pacific Ocean, the Atlantic Ocean and the Indian Ocean account for 46%, 24% and 20% of the total ocean area of the earth respectively. Most of the important marginal seas are distributed in the northern hemisphere, and some are surrounded by continents or islands. The largest is the Arctic Ocean and its offshore waters, the European Mediterranean Sea is between Australia and Southeast Asia, the Caribbean Sea and its adjacent waters, Mediterranean Europe, the Bering Sea, the Sea of Okhotsk, the Yellow Sea, the East China Sea and the Sea of Japan.

ocean temperature

Seawater temperature is a physical quantity reflecting the thermal state of seawater. The water temperature of the world's oceans generally varies between -2℃ and 30℃, and the area with annual average water temperature exceeding 20℃ accounts for more than half of the whole ocean area. The sea water temperature varies periodically and irregularly with the day, month, year and year, which mainly depends on the ocean heat budget and its time change. Generally speaking, the factors affecting the surface water temperature of the ocean are tides, solar radiation, coastal topography, meteorology, ocean currents and so on. Direct observation shows that the daily variation of seawater temperature is very small, and the water depth ranges from 0 to 30 meters, while the annual variation can reach about 350 meters. There is a constant temperature layer at a water depth of about 350 meters. However, with the increase of depth, the water temperature gradually decreases 1000m, which is about 1℃-2℃, and the water temperature reaches 2℃- 1℃ at the depth of 3000m-4000m. Sea water temperature is one of the most important factors in marine water literature, and it is often used as a basic index to study the properties and describe the movement of water masses. Studying the temporal distribution and variation of seawater temperature is not only an important content of oceanography, but also of great significance to meteorology, navigation, fisheries and underwater acoustics.

According to the marine ecological survey report released by NOAA on April 26th, 20 13, local time, the SST on the continental shelf in the northeastern United States reached a new high in 20 150. It is higher than the average temperature in the spring and summer of last year, and it tends to increase gradually, reaching 14 degrees Celsius, exceeding the data of 195 1 year, while the sea temperature in recent 30 years is usually lower than 12.4 degrees Celsius.

saltness

The salt content of seawater in the world's major oceans varies from place to place, with an average of about 3.5%. The most common inorganic salt dissolved in seawater is sodium chloride, which is used daily. Some salt comes from volcanoes under the sea, but most of it comes from rocks in the earth's crust. Rock is decomposed by weathering, releasing salt, which is carried to the sea by river water. In the circulation process of seawater evaporation and condensation into water, after seawater evaporation, salt remains and gradually accumulates to the existing concentration. The ocean contains so much salt that it can spread a salt layer about 500 feet thick on the global land.

Affect the climate

The ocean is one of the main factors that determine the development of the earth's climate. The ocean itself is the largest heat storage body on the earth's surface. Ocean current is the largest heat energy conveyor belt on the earth's surface. The gas exchange between the ocean and the air, the most important of which is water vapor, carbon dioxide and methane, has great influence on climate change and development.

The difference between ocean and ocean

The ocean is the central part of the ocean and the main body of the ocean. The total ocean area in the world accounts for about 89% of the ocean area. The water depth of the ocean is generally above 3000 meters, and the deepest point can reach 10000 meters. The ocean is far from the land and is not affected by the land. Its water temperature and salinity have not changed much. Every ocean has its own unique ocean current and tidal system. The water in the ocean is blue and transparent, and there are few impurities in the water. There are five worlds, namely Pacific Ocean, Indian Ocean, Atlantic Ocean, Arctic Ocean and Southern Ocean.

{Antarctic Ocean (Southern Ocean), also known as "Antarctic Sea" and "Southern Ocean", is the fifth confirmed ocean in the world and the only ocean in the world that completely surrounds the earth but is not divided by the mainland. The Antarctic Ocean is the ocean around Antarctica, and it is the sea area of the Pacific Ocean, the Atlantic Ocean and the southern Indian Ocean. It has always been thought that the Pacific Ocean, the Atlantic Ocean and the Indian Ocean extend to Antarctica, and the waters of the Antarctic Ocean are regarded as the Antarctic Sea. However, because oceanography found that there are important different ocean currents in the Antarctic Ocean, the International Hydrographic Organization identified it as an independent ocean in 2000 and became the fourth ocean among the five oceans. However, there are still people in the academic circles who think that the ocean should have its corresponding mid-ocean ridge. }

The ocean at the edge of the ocean is an accessory part of the ocean. The area of the sea accounts for about 1 1% of the ocean, and the water depth of the sea is relatively shallow, with an average depth of several meters to 2~3 kilometers. The sea is close to the mainland and is influenced by the mainland, rivers, climate and seasons. The temperature, salinity, color and transparency of seawater are all affected by land and have obvious changes. In summer, the sea gets warmer and the water temperature drops in winter. In some sea areas, seawater will freeze. Where the river flows into the sea, or in the rainy season, the sea water will weaken. Due to the influence of land, rivers carry sediment into the sea, and the offshore seawater is turbid and the transparency of seawater is poor. The sea has no independent tides and currents. The ocean can be divided into marginal sea, inland sea and Mediterranean sea. The marginal sea is not only the edge of the ocean, but also close to the continental front; This kind of sea is widely connected with the ocean and is generally separated from the ocean by a group of islands. China's East China Sea and South China Sea are marginal seas of the Pacific Ocean. The inland sea is a sea located on the mainland, such as the Baltic Sea in Europe. The Mediterranean Sea is a sea between several continents, and its water depth is generally deeper than that of the inland sea. There are nearly 50 major oceans in the world. The Pacific Ocean is the largest, followed by the Atlantic Ocean, the Indian Ocean is similar to the Arctic Ocean, and the Antarctic Ocean is the least.

? The cause of the formation of the ocean:

Current research proves that some large and small nebulae were separated from the solar nebula about 5 billion years ago. They revolve around the sun while rotating. In the process of movement, they collided with each other, and some lumps combined with each other, from small to large, and gradually became the original earth. During the collision of nebula clusters, they shrink sharply under the action of gravity, and the radioactive elements in them degenerate, which makes the primitive earth heat up continuously. When the internal temperature reaches high enough, underground substances, including iron and nickel, begin to melt. Under the action of gravity, the weight sinks and tends to concentrate in the center of the earth, forming the core; Lighter ones float to form the crust and mantle. At high temperature, the water inside evaporates, rushes out with the gas and rises into the air. But because of gravity, they will not run away, but will only turn around the earth and become a circle of air and water.

In the process of cooling and condensation, the crust on the earth's surface is constantly impacted and squeezed by the violent movement inside the earth, so it becomes uneven and sometimes crushed, forming earthquakes and volcanic eruptions, spewing magma and hot gas. At first, this kind of situation often happens, and then it gradually decreases and tends to be stable. This division of light and heavy substances led to great turmoil and reorganization, which was completed about 4.5 billion years ago.

After the crust is cooled and shaped, the earth is like an apple that has been dried for a long time, and its surface is wrinkled and uneven. There are mountains, plains, river beds and basins.

For a long time, the water vapor in the sky coexisted with the atmosphere. Thick clouds are gathering. It's dark. With the gradual cooling of the earth's crust, the temperature of the atmosphere is also slowly decreasing. Water vapor takes dust and volcanic ash as condensation nuclei and becomes water droplets, which accumulate more and more. Due to uneven cooling and strong air convection, thunderstorms and turbidity currents were formed, and it rained harder and harder for a long time. Surging floods, through thousands of rivers and valleys, converge into a huge water body, which is the primitive ocean.

In the primitive ocean, seawater is not salty, but acidic and anoxic. Water is constantly evaporating, and clouds repeatedly cause rainfall, and then fall back to the ground, dissolving the salt in the rocks on the land and under the sea, and continuously collecting it into the seawater. After hundreds of millions of years of accumulation and integration, it has become a generally uniform salt water. At the same time, because there was no oxygen and ozone layer in the atmosphere at that time, ultraviolet rays could reach the ground directly. With the protection of seawater, life was first born in the ocean. About 3.8 billion years ago, organic matter was produced in the ocean, and lower single-celled organisms first appeared. In the Paleozoic era 600 million years ago, there were algae that photosynthesized in the sun to produce oxygen, which gradually accumulated and formed the ozone layer. At this time, creatures began to land.