Oceans account for 70.8% of the entire Earth's surface area and reach an average depth of 3,800 meters. The ocean is not only the birthplace of many creatures, but also the ideal place for them to grow and inhabit. Among the various marine animals, in addition to the common fish, crustaceans and cephalopods, corals also occupy a very important position in marine life species, biological fossils, ecosystems and marine productivity.
Huge family
Studies have shown that corals began to survive from the Cambrian Period,
It has a history of more than 600 million years. According to incomplete statistics, in the Paleozoic, they had about 1400 genera and more than 10000 species; since the Mesozoic Era, the number of their genera has increased significantly; there are about 6500 species of corals. From ancient times to the present, corals have been a large family of marine animals.
Corals are not only diverse, but also widely distributed, and they can be found in all oceans and even continents of the world. Living corals are found in large numbers in the ocean, mainly in shallow tropical and subtropical seas. In the shallow waters of temperate and cold zones, there are also many coral species. They have also been found in the deep-sea waters of the cold zone, such as scientists who have found a black horn coral at a depth of 8800 meters in the ocean.
Corals can be described as diverse in shape, including twigs, antlers, hives, mushrooms, reishi, human brains, bamboo knots and mountain stones. Corals are more colorful, showing red, orange, yellow, green, cyan, blue, purple, brown, as well as peach, orange, white and black. It can be said that corals combine strange forms and beautiful colors, which can be called the magical creation of nature.
However, when people view corals on land, they can only see the mineralized bones of corals, not the thin layer of polyps (hydra bodies) covered on the surface of their bones when they live in seawater.
Living corals belong to the order Polyps and are generally divided into two suborders: the suborder 8-amphib coral and the suborder Hexacarp coral. The pinnate branches of the former have 8 tentacles and 8 diaphragms, while the tentacles of the latter are not branched, and the diaphragms are usually paired, mostly in multiples of 6.
Most of the six-placed corals have hard calcareous exoskeletons, individuals are very small but grow in groups, several of which are reef-building corals, which grow along the edge of continents or islands and can form atolls, with a diameter of up to 65 to 80 km. Barrier reefs can also be formed, such as the famous Australian Great Barrier Reef,
Up to 2000 km. The black corals in the six corals are named after the black color of all the animals of this order. The height of their groups is only a few centimeters, and the largest can reach 2 to 3 meters, which can be called the "giant" in coral.
Both eight and six corals belong to shallow sea corals. Deep in the ocean on the eastern side of the Atlantic Ocean, there is also a wide variety of deep-water corals that are not well known. This cold coral belt is 4500 kilometers long.
Great contribution
Corals are a group of organisms that grow together with many polyps (hydra bodies), a few of which are made up of a single hydra. Individual hydra bodies produce many new hydra bodies in a split or budding manner, which then aggregate into groups. As they continue to grow, the fertilized eggs in the hydra develop into larvae, float with the current and expand to other sea areas, and once they encounter the hard seabed, they attach, fix, grow, and gradually develop into another new coral group.
Polyps continue to grow and divide throughout their lives. This unique way corals grow makes them almost never die or have no end in life. Therefore, corals are like "perpetual motion machines". If the marine environmental conditions are suitable for coral growth and habitat, the calcareous or bone basal disc formed by the hydra body group will grow endlessly, and the coral reef will grow day by day. After millions of years, the small polyps have finally created a coral reef with a total area of 600,000 square kilometers in the world, becoming a "big garden under the sea" that will never fade, making tourists linger.
In the water layer of tens of meters in the coral reef waters of various parts of the world, coral reefs and other organisms, such as algae, sponges, polychaetes, bivalves, starworms, copepods, barnacles and spinosaurs, form a symbiotic relationship, they are both interdependent and compete with each other, forming today's countless large-scale coral reef ecosystems, making outstanding contributions to improving the productivity of the entire ocean.
Around the reef, there are also many fish, crustaceans and molluscs. For example, in the Philippines, there are 2177 species of reef fish; in the Great Barrier Reef, there are 1500 species of reef fish; in Taiwan Province, China, there are more than 1500 species of reef-dwelling ornamental fish, such as the brocade echinoflora, the tentacled catfish, the white-tailed starfish, the spotted skin peeler and the large-leaf sea dragon, etc., all of which are strange in shape, bright in color and highly valuable in ornamental value.
Fish swim in the waters surrounding coral reefs, creating a unique landscape that is lively and colorful. Many peoples have gradually established their states based on large coral reefs, such as Kiribati, Tuvalu, Samoa and maldives. Coral reefs lay the foundation for the lives and economic development of the people of these countries.
The history of corals shows us their tenacious vitality. However, corals also have a fragile side. For example, reef-making corals in shallow tropical seas are quite sensitive to changes in marine environmental conditions. In the process of global industrialization, the ocean dissolves excess carbon dioxide, causing the ocean to acidify,
Put corals to a severe test. Coral growth usually requires an average annual water temperature of more than 20 °C, the optimal water temperature is 25 °C ~ 26 °C, the lower water temperature limit is 21 °C ~ 22 °C, and the upper limit is 31 °C ~ 32 °C. At the same time, salinity, turbidity, dissolved oxygen, flow rate, bait and predators all have a greater or lesser impact on the growth and reproduction of corals. When these factors change drastically, they endanger the lives of corals.
In addition, the growth rate of corals varies greatly depending on their species, age and environment. In general, shallow tropical or subtropical corals with young, sparsely boned corals grow faster, while temperate or boreal deep-sea, older, and more skeletal corals grow more slowly. Scientists have observed that dendritic corals grow 38 centimeters in 344 days, some horned corals can even grow several centimeters per week, and some bulk corals only grow a few millimeters per year.
Precious
Although there are many kinds of corals, there are very few people with strong bones and natural beauty, and these corals are rare in number and grow in the depths of the ocean, so it is quite difficult to collect, so it has become a treasure in corals. The precious and rare coral species are almost all red corals in the suborder Eight-Ampers and Black Corals in the Suborder Hexacarp Corals.
Japanese red coral
There are 7 species of red coral, but not all of them are precious. Japanese red coral is the most famous and precious species of red coral. Its groups are dendritic, with short twigs in front of or on the sides of the branches. The bones are hard and beautiful, dark red or orange-red, the central axis or lower branches are white, and the radial white flowers on the branches are water hydras, reaching a height of more than 30 cm. Japanese red corals are distributed in the sea off Tosa Bay in Japan, off the Goto Islands, Kagoshima and Ogasawara Islands, as well as in the sea off Taiwan Island and the diaoyu Islands of China, and most of them are fixed on the rocks on the seabed at a depth of 100 to 200 meters.
There is also a type of pink coral, which is the most precious species of red coral. Its bones are peach-red, with a white center and a height of about 1 meter, growing deeper than Japanese red corals.
The history of the use of red coral dates back to the early Common Era. In some parts of Africa, red coral skewers have been given special religious meanings and are regarded as the most precious gifts given to rulers. In 18th-century France, a red coral necklace called "blood rosary beads" was popular. In Tibet, China, red coral is given a deep religious meaning, it is said that red is the symbol of the incarnation of the Buddha, so the red coral has become a deity in Buddhist temples and an ornament for devout Buddhists.
Ancient and modern, Chinese and foreign, the royal family and the upper class have a fondness for precious red corals. Queen Elizabeth I and II of the United Kingdom wore red coral jewelry; the Qianlong Emperor and his empress of the Qing Dynasty in China wore red coral necklaces on major occasions; in the Yangxin Hall of the Forbidden City in Beijing, and the Chuxiu Palace, which was once the residence of Empress Dowager Cixi, in its extremely luxurious and luxurious furnishings, red coral was placed in a prominent position.
According to historical records, Spanish red corals were once so popular that their prices became quite expensive. In 1822, Spanish red coral raw material sold for as much as $100 per pound. In the early 1980s, the price of raw materials for red coral in Taiwan was as expensive as gold, and the price of whole red corals with good quality, shape and color was many times that of gold. In recent years, the market for precious red corals has increased day by day.
The preciousness of red coral also lies in its certain health care function. Li Shizhen recorded in the "Compendium of Materia Medica" that red coral has the function of removing the eyes and calming the gods. Abroad, it was believed for centuries that red corals would change hue depending on the health of the wearer.
At present, the global production of red coral is very small, and the price is increasing day by day. In order to allow the precious red coral resources to recuperate and gradually recover, Japan has begun to implement effective conservation of coral fisheries. At the same time, Japan has also carried out experiments on the proliferation of red corals, but because red corals are growing quite slowly, they have not yet entered the practical stage.
Deep-sea blackhorn corals
On the tropical and subtropical deep seabed (below 100 m water depth), black horn corals are widely distributed. Some of the bones of black horn corals are very strong and suitable for processing into ornaments. In addition, in the Kuril-Kamchatka Trench in the northwest Pacific Ocean, scientists discovered a deep-sea black horn coral at a depth of 8175 to 8840 meters in 1971.
Since ancient times, black horn coral has been regarded as a treasure in coral, it not only has a natural magical form and excellent texture, but also is often used to treat eye diseases and as a raw material for formulating sex hormones. In modern society, it is an international fashion to use black horn coral as an ornament, and the Japanese especially like to use it to make super kimonos when decorating the belt buckle.
In and around the Caribbean Sea and hawaii in the United States, black horn corals are relatively rich in resources and still have certain potential for development and utilization. However, black horn corals are particularly sensitive to irrational harvesting, and because of this ecological characteristic, the countries concerned have taken some rational development measures aimed at protecting this precious marine animal resource.