The sea in nature

1. Introduction

The sea (seas and oceans; the ocean; the sea) is the ocean. In fact, there are some differences between sea and ocean. The difference between sea and ocean:

The vast ocean, from blue to turquoise, is beautiful and spectacular. Ocean, ocean. People always say this, but many people don't know that the sea and the ocean are not exactly the same thing, they are different from each other. So, how are they different, and how do they relate?

The ocean is the central part of the ocean and the main body of the ocean. The total area of ??the world's oceans accounts for approximately 89% of the ocean area. The water depth of the ocean is generally more than 3,000 meters, and the deepest can reach more than 10,000 meters. The ocean is far away from the land and is not affected by the land. Its moisture and salinity vary little. Each ocean has its own unique system of currents and tides. The water color of the ocean is blue, very transparent, and there are very few impurities in the water. There are four oceans in the world, namely the Pacific Ocean, the Indian Ocean, the Atlantic Ocean, and the Arctic Ocean.

The sea is at the edge of the ocean and is a subsidiary part of the ocean. The area of ??the sea accounts for about 11% of the ocean. The water depth of the sea is relatively shallow, with the average depth ranging from a few meters to two or three thousand meters. The sea is close to the continent and is affected by the continent, rivers, climate and seasons. The temperature, salinity, color and transparency of the sea water are all affected by the land and have obvious changes. In summer, the sea water warms and in winter the water temperature drops; in some sea areas, the sea water even freezes. Where large rivers enter the sea, or during rainy seasons, the sea water becomes fresher. Due to the influence of the land, rivers carry sediment into the sea, making the nearshore seawater turbid and unclear, and the transparency of the seawater is poor. The sea does not have its own independent tides and currents. The sea can be divided into marginal sea, inland sea and Mediterranean Sea. The marginal sea is both the edge of the ocean and the frontier of the continent; this type of sea is widely connected with the ocean and is generally separated from the ocean by a group of islands. my country's East China Sea and South China Sea are the marginal seas of the Pacific Ocean. Inland seas are seas located inside continents, such as the Baltic Sea in Europe. The Mediterranean Sea is a sea between several continents, and the water depth is generally deeper than that of inland seas. There are nearly 50 major seas in the world. The Pacific Ocean has the most, followed by the Atlantic Ocean, and the Indian Ocean and the Arctic Ocean are about the same.

2. The formation of the ocean

How was the ocean formed? Where does seawater come from?

Science is currently unable to provide a final answer to this question. This is because they are connected with another universal and equally unresolved issue of the origin of the solar system.

Current research proves that about 5 billion years ago, some large and small nebula clumps were separated from the solar nebula. They revolve around the sun and spin on their own. During the movement, they collided with each other, and some lumps combined with each other, growing from small to large, and gradually became the primitive earth. During the collision of nebula clumps, they contracted sharply under the action of gravity, and the internal radioactive elements decomposed, causing the primitive earth to be continuously heated. When the internal temperature reached a high enough level, the materials in the earth, including iron, nickel, etc., began to melt. Under the action of gravity, the heavy ones sink and concentrate towards the center of the earth, forming the core; the light ones float up, forming the crust and mantle. At high temperatures, the moisture inside vaporizes and rushes out together with the gas, flying into the air. However, due to the gravity of the earth's center, they will not run away and will only form a circle of air and water around the earth.

The layer of crust located on the surface of the earth is constantly impacted and squeezed by the violent movements inside the earth during the cooling and condensation process. As a result, it becomes wrinkled and uneven, and sometimes it is squeezed, causing earthquakes and volcanoes. Exploded, spewing out magma and hot gas. At first, this happened frequently, then gradually became less frequent and gradually stabilized. This process of differentiation of light and heavy materials, resulting in great turbulence and reorganization, was probably completed 4.5 billion years ago.

After the crust is cooled and shaped, the earth is like a long-dried apple, with densely wrinkled and uneven surfaces. Mountains, plains, river beds, ocean basins, all kinds of terrain are available.

For a long period of time, water vapor and the atmosphere in the sky coexisted together; there were dense clouds. The sky is dark and the earth is dark. As the earth's crust gradually cools, the temperature of the atmosphere also slowly decreases. Water vapor uses dust and volcanic ash as condensation nuclei and turns into water droplets, accumulating more and more. Due to uneven cooling and violent air convection, thunder and lightning winds were formed, and heavy rain and turbid currents were formed. The rain became heavier and heavier, and it continued to rain for a long time. The torrential floods passed through thousands of rivers and ravines and gathered into a huge body of water. This is the primitive ocean.

In the primitive ocean, seawater is not salty, but acidic and anoxic. The water continues to evaporate, causing rain due to repeated topography, and then falls back to the ground, dissolving the salt in the land and seabed rocks, and continuously collecting it in the sea water. After hundreds of millions of years of accumulation and fusion, it turned into generally uniform salt water. At the same time, because there was no oxygen and no ozone layer in the atmosphere at that time, ultraviolet rays could reach the ground directly. With the protection of sea water, life was first born in the ocean. About 3.8 billion years ago, organic matter was produced in the ocean, and first there were lower single-celled organisms. In the Paleozoic Era 600 million years ago, seaweeds began to photosynthesize in the sun, producing oxygen, which slowly accumulated to form the ozone layer. At this time, creatures began to land on land.

In short, through the gradual increase in water volume and salt content, as well as the vicissitudes of geological history, the primitive ocean gradually evolved into today's ocean.

3. Ocean—the medicine storehouse of the 21st century

Theme words or keywords: Marine science

According to relevant medical experts’ predictions, humans will be subdued in the 21st century cancer. So, what kind of panacea do humans rely on? In recent years, scientists have discovered after research that the ocean will become the medicine storehouse of the 21st century.

Sea cucumber is a valuable seafood containing high protein. However, you may not have thought that several species of sea cucumbers release a toxin from the anus that has tumor-inhibiting effects.

Oyster - this small shellfish is very delicious, but its greater value is because it contains an antibiotic. This antibiotic has anti-tumor effects.

Currently, some researchers in the pharmaceutical industry are conducting experiments to extract toxic compounds from seaweed and tiny marine organisms as an effective means of treating certain diseases. Preliminary experiments show that toxic substances extracted from certain sponge-like organisms can inhibit the development of cancer cells. A certain substance extracted from the enema fish can help treat diabetes. An American expert on marine issues vividly said: "Marine life is like a consultation center that can provide solutions to health problems."

In When considering harvesting medicine from the ocean, medical experts attach great importance to the development and utilization of corals. Experiments have shown that toxic substances extracted from coral reefs, like poisons extracted from certain sponge-like organisms, also have the effect of inhibiting the development of cancer cells; other substances extracted from coral reefs can alleviate arthritis and asthma. Inflammatory effect. There is a kind of coral produced in Hawaii. It contains highly toxic substances and can be used to make special medicines for the treatment of leukemia, high blood pressure and some cancers. An extract of soft coral from the South China Sea has the effects of lowering blood pressure, anti-arrhythmia and antispasmodic effects.

Shark is an ancient marine fish, widely distributed around the world, with more than 250 species. Since the mid-1980s, many international scientists have conducted careful research on the pharmacology, chemistry, biochemistry and applications of various parts of the shark's body. In particular, the research on anti-tumor active substances in sharks has attracted more attention. According to relevant reports, American biologists have conducted decades of research on sharks and found that sharks hardly suffer from any disease, and rarely get cancer. They seem to have natural immunity to cancer. Some scientists have inoculated some pathogenic bacteria and cancer cells into sharks, but they cannot make them sick. It seems that sharks have some kind of special protective chemical inside their bodies.

Relevant Chinese experts’ research on sharks is almost in sync with that of the international community. In 1985, experts from the Shanghai Fisheries Institute and the Shanghai Cancer Institute discovered for the first time that shark serum has a killing effect on human erythrocytic leukemia tumor cells in vitro. This scientific research result has opened up a vast world for mankind to search for anti-tumor drugs from marine biological resources.

5. Ocean - the cornucopia of mineral resources

Subject words or keywords: Marine science

The ocean is the cornucopia of mineral resources. After the "International 10-year Ocean Exploration Phase" in the 1970s, mankind has further deepened its understanding of the types, distribution and reserves of marine mineral resources.

(1), Oil and gas fields

With the modernization of human economy and life, the demand for oil is increasing day by day. In modern times, oil plays the first role in energy. However, some large oil fields on land, which are relatively easy to exploit, have been exhausted and some are on the verge of exhaustion. For this reason, in the past 20 to 30 years, many countries in the world are making great efforts to develop the offshore oil industry.

Detection results show that the world’s oil resource reserves are 1,000 billion tons, and the recoverable amount is about 300 billion tons, of which seabed reserves are 130 billion tons.

China has a shallow sea continental shelf of nearly 2 million square kilometers. Through geological surveys of submarine oil fields, seven large basins have been discovered, including the Bohai Sea, the South Yellow Sea, the East China Sea, the Pearl River Estuary, the Beibu Gulf, the Yingge Sea and the Taiwan Shoal. Among them, the East China Sea is rich in seabed reserves, comparable to the North Sea oil fields in Europe.

The Pinghu Oil and Gas Field in the East China Sea is the first medium-sized oil and gas field discovered in the East China Sea, located 420 kilometers southeast of Shanghai. It is a medium-sized oil and gas field mainly composed of natural gas, with a depth of 2,000 to 3,000 meters. According to relevant expert estimates, natural gas reserves are 26 billion cubic meters, condensate oil 4.74 million tons, and light crude oil 8.74 million tons.

(2), Rare manganese nodules

Manganese nodules are a source of rare metal minerals on the seabed. It was first discovered in the Atlantic Ocean in 1973 by a British marine survey ship. But the world's formal organized investigation of manganese nodules began in 1958. Investigations show that manganese nodules are widely distributed at the bottom of the deep sea at 4,000 to 5,000 meters. They are the largest metal mineral resources available in the future. Interestingly, manganese nodules are a variety of raw minerals. It is growing at a rate of about 10 million tons every year and is an inexhaustible mineral.

The total reserves of manganese nodules in the world's oceans are about 3 trillion tons, including 400 billion tons of manganese, 8.8 billion tons of copper, 16.4 billion tons of nickel, and 4.8 billion tons of cobalt, respectively. Dozens or even thousands of times the amount.

Based on current consumption levels, these manganese can be used by the world for 33,000 years, nickel for 253,000 years, cobalt for 21,500 years, and copper for 980 years.

At present, with the in-depth exploration and investigation of manganese nodules and the relatively mature technology, it is expected that by the 21st century, it can enter the commercial development stage and formally form the deep-sea mining industry.

(3) Undersea hydrothermal mineral deposits

In the mid-1960s, a U.S. oceanographic survey ship first discovered deep-sea hydrothermal mineral deposits in the Red Sea. Later, some countries successively discovered more than 30 such mineral deposits in other oceans.

Hydrothermal mineral deposits, also known as "heavy metal mud", are formed by high-temperature lava ejected from cracks in sea ridges (seamounts), washed, precipitated, and accumulated by sea water. They can, like plants, Growing rapidly at a rate of several centimeters per week. It contains dozens of rare and precious metals such as gold, copper, and zinc, and the grades of gold, zinc, and other metals are very high, so it is also known as the "Undersea Gold and Silver Treasury." Interestingly, heavy metals are colorful, including black, white, yellow, blue, red and other colors.

Under current technical conditions, although seafloor hydrothermal mineral deposits cannot be mined immediately, it is a potential treasure trove of seafloor resources. Once industrial mining can be carried out, it will become one of the four major seabed minerals in the 21st century, along with seabed oil, deep-sea manganese nodules and seabed sand deposits.

6. Ocean - the granary of the future

Theme words or keywords: Marine science

Some readers may think that food cannot grow in the ocean. How can it become the granary of the future?

Yes, rice and wheat cannot be grown in the ocean, but the fish and shellfish in the ocean can provide humans with delicious and nutritious protein food.

As we all know, protein is the most important substance that constitutes living organisms, and it is the basis of life. Currently, only 5% to 10% of the protein consumed by humans is provided by the ocean. What is worrying is that since the 1970s, marine fisheries have been stagnant, and many species have been depleted. To use a folk saying, now humans have eaten almost all the grandchildren of the yellow croaker. For the ocean to become a veritable granary, fish production will need to increase at least ten times compared to today. Experiments at a marine farm in the United States show that it is entirely possible to significantly increase fish production.

In nature, there are countless food chains. In the ocean, where there are seaweeds there are shellfish, and where there are shellfish there are small fish and even big fish... The total area of ??the ocean is more than double that of land, and most of the few fishing grounds in the world are located offshore. This is because algae growth requires sunlight and compounds such as silicon and phosphorus, and these conditions are only available in offshore areas close to land. Marine surveys show that silicon and phosphorus are very abundant in deep seawater below 1,000 meters, but they cannot float to the warm surface layer. Therefore, there are only a few small sea areas, where due to the action of natural forces, deep water automatically rises to the surface layer, causing these sea areas to grow densely with algae and dense fish, making them rare fishing grounds.

Oceanographers were inspired by these sea areas. They used the principle of upwelling currents to artificially pump deep seawater to the surface layer in sea areas with strong sunlight, and then cultivated seaweed there. Seaweed is used to raise shellfish, and the processed shellfish is used to raise lobsters. Surprisingly, this series of experiments were successful.

Relevant experts optimistically pointed out that the potential of ocean granaries is great. Currently, the annual yield per hectare of land crops with the highest yield is only 0.71 tons when converted into protein. In scientific experiments, the output of seawater breeding in the same area can reach up to 27.8 tons, and the output with commercial competitiveness is also 16.7 tons.

Of course, there will be many difficulties in moving from scientific experiments to actual production. Chief among them is the considerable amount of electricity required to pump water from depths below 1,000 meters. Where does such a huge amount of electricity come from? Obviously, under today's conditions, these energy requirements cannot be met.

However, scientists have found a trick: they are preparing to use the temperature difference between the surface layer and the deep ocean in tropical and subtropical seas to generate electricity. This is the so-called seawater temperature difference power generation. That is to say, the designed marine breeding farm will be combined with the seawater temperature difference power station.

According to calculations by relevant scientists, due to the strong sunlight in tropical and subtropical sea areas, there are as many as 6,250 trillion cubic meters of warm water available for power generation in this sea area. If people use 1% of warm water to generate electricity each time, pump the same amount of deep sea water for cooling, and use this electricity for breeding, 750 million tons of various types of seafood can be obtained every year. It is equivalent to four times the total amount of fish and meat consumed by humans in the mid-1970s.

Through these simple calculations, it is not difficult to see that it is completely feasible for the ocean to become the future breadbasket of mankind