Coral is an extremely vital animal. Coral has thrived in the sea since ancient times. In tropical and subtropical shallow seas, coral reefs are formed by the accumulation of reef-building coral skeletons and biological debris. At first, people regarded coral as a plant, and later regarded it as a mineral. It was not until the18th century that a man named Linnai called coral a plant-like animal. Although it is not clear whether corals are animals, plants or others, humans have never stopped destroying corals.
This year1October 20th, 165438+ The International Union for Conservation of Nature and Natural Resources, the world's largest environmental protection organization, issued a press release saying, "Although so many coral reefs are on the verge of extinction, efforts to save coral reefs have not been taken seriously." Coral with tenacious vitality is surrounded by many killers cultivated by human beings, and its future is worrying.
Murder at sea
Streeter, a 30-year-old British woman, is now the world record holder for free diving. When she was a child, she used to swim in coral reefs in the Caribbean with diving pipes, but now these coral reefs no longer exist. She is worried that her grandchildren may not know what coral reefs look like. Researchers from the University of East Anglia in the United Kingdom recently published an article in the online edition of the American magazine Science, which confirmed what streeter observed. According to the article, in the past 30 years, the coral coverage in some parts of the Caribbean has dropped sharply from 50% to about 10%. The survey includes 263 coral reefs in the Caribbean basin, south to the coast of South America, north to Jamaica and Florida, and west to the Gulf of Mexico near the coast of Texas. Although the speed of coral disappearance has slowed down, the situation is still not optimistic, and it may take decades to recover.
"The corals in the world are no longer native," concluded John Pandoffi, who works at the American Museum of Natural History. "Whether it is Bermuda in the17th century or the Red Sea tens of thousands of years ago, once humans developed it, the same tragedy began to be staged: large carnivorous fish (such as sharks) and turtles were killed first, then smaller fish, and finally algae and corals themselves." Killing for money, if the victim is human, will be a serious crime, and the unscrupulous descendants of the crime may be sentenced to death by the court; But if the victim is replaced by coral, people may ignore its harm. Jose Luis luis garcia, coordinator of eco-climate change in Greenpeace, said: "Coral reefs are islands themselves. In many cases, they play a role in dividing the ocean or preventing coastal corrosion." For some developing countries, they are still a tourism resource and the only source of income for these countries. For these coral reef countries, tourism alone can generate billions of dollars in revenue every year. In addition, 1/4 fish consumed and sold in these countries are also caught in coral reef waters. Some chemicals extracted from coral can also be used to make drugs to treat herpes, arthritis, asthma and some nervous system diseases.
It's human's fault again
The specific cause of coral death is still controversial, but most people think that human activities have caused coral death.
The first killer of coral is global warming. In reef-building corals, * * * has a large number of zooxanthellae, and it is they that dye corals with gorgeous colors. Insect yellow algae can carry out photosynthesis, while producing nutrients and removing metabolic wastes (carbon dioxide, etc.). ) and provide oxygen for the growth of reef-building corals. However, coral is a creature and extremely sensitive. If the temperature of seawater exceeds a certain range, corals will abandon zooxanthellae and turn white again. If the worm algae don't come back, the coral will die. The first albino coral reef was discovered on an expedition to the Great Barrier Reef in Australia 70 years ago. However, in the 1970s, albino corals were found all over the world. According to a report by the World Wildlife Fund, 60 cases of coral bleaching were found in the short period of 12 from 1979 to 190, while only 3 cases were confirmed in the previous 103. Aowei Hogg Gulberg, a professor at the School of Biological Sciences, University of Sydney, studied the global albino coral reefs in recent 15 years. In his research report, he concluded that unless the climate does not change, coral bleaching will become more and more frequent, and this phenomenon will occur every year from 2030 to 2070. /kloc-after 0/00 years, coral reefs will disappear from most parts of the earth.
The second killer of coral is agricultural farming. In reunion island and Mauritius, due to the extensive use of chemical fertilizers in agricultural production, the bacteria killer microorganisms of coral reappeared in the ocean, threatening coral reefs. Microbial stone is a kind of structure composed of marine microbial groups (bacteria and cyanobacteria), which generally breeds and proliferates less than 25 meters underwater. In some sea areas, microbial rocks can spread all over the seabed at an alarming rate, making corals unable to touch the light, thus killing them.
The third killer is fishing, which will cause direct damage to corals. Shrimp has recently become popular in America. Although the economy is depressed, the high-end seafood restaurants are still doing brisk business, and the diners are in an endless stream. However, wild shrimp live on the bottom of the sea, and people need to catch them with trawls and weighted nets. Where fishing nets pass, the marine environment is destroyed.
There are many coral killers. Researchers from the Australian National University found that during the Indonesian forest fire in 1997, smoke enveloped the nearby sea surface, which led to an explosive increase in the number of toxic phytoplankton in the sea water, forming a red tide, and almost all corals in Fiona Fang were killed for hundreds of kilometers.
Save coral
Some scientists believe that the only way to protect corals is to establish a larger international coral reserve where fishing and anchoring are not allowed. However, some scientists hope that artificial reefs can save the decline of corals. Since 1950s, people began to build artificial reefs with metal scrap and automobile tires, hoping to increase the production of fish and crustaceans. Recently, people use plastics, steel and cement to build reefs, but they are much worse than natural reefs, and the effect of attracting corals is not good. However, more complex reefs may be more effective. The idea came into being in the mid-1970s, when Hill Bates, who worked at the University of Texas, wanted to use electrodes immersed in seawater to simulate the growth of shells and reefs. When electrons combine with hydrogen ions in seawater, electrolyzed water will produce hydrogen bubbles at the cathode. In order to make up for the lost hydrogen ions, carbonic acid in seawater will decompose near the cathode, releasing hydrogen ions and carbonate ions. Hilbert noticed that when the concentration of carbonate ions reached a certain level, the cathode would form a limestone mainly composed of calcium carbonate. Hilbert speculated that if renewable energy such as solar energy is used to generate electricity, people can make limestone "reefs" of various shapes and sizes at low cost. In his experiments, he found that the thickness of steel frame accessories can be increased by 5 cm every year. This structure needs almost no maintenance, and it can even repair itself once it is damaged. When this limestone looks like a natural reef, corals will soon breed on it.
This method has attracted the attention of new york Metro. New york Public Transport Company intends to sink 650 scrapped subway cars into the Atlantic Ocean near the coast of New Jersey, hoping that these cars will become artificial coral reefs to attract shellfish, fish and shrimp. However, this method of dumping a large amount of waste into the sea needs some control, otherwise, coastal countries around the world may dump their garbage into the sea in front of their own doors without restraint, and then human beings will really be buried in the sea of garbage.