With the sharp increase of man-made carbon dioxide in the atmosphere, more carbon dioxide enters the ocean. About 30% of carbon dioxide in the atmosphere is absorbed by the ocean, which leads to the decrease of pH value and the increase of acidity of seawater, which is called ocean acidification. The pH value has only dropped by 0.05 since 1990, and it is estimated that it will only drop by 0.3 to 0.5 in the future. But recalling high school chemistry, pH value is the logarithm of hydrogen ion concentration. Every time the pH value of 0. 1 increases, the hydrogen ion concentration changes by about 29%, so it seems to change quite a lot. ? Biological requirements for pH are very strict, and coral reefs and their ecosystems are the first to be affected. ? Coral polyps gather into rich coral reefs by forming calcium carbonate bones, which provide living environment for fish and other animals. The solubility of calcium carbonate will gradually increase with the increase of acidity, that is to say, ocean acidification will make coral reefs white or even dissolve "calcium deficiency". Coral reef ecosystem is the most productive ecosystem in the ocean and is called "tropical rain forest in the ocean". Although it only accounts for 0. 1% of the ocean area, about 2 1% of marine species depend on coral reefs for survival. The economic loss caused by ocean acidification of coral reefs is estimated to be 30-375 billion yuan per year, even as high as 1 trillion. As for the hard-to-quantify ornamental value, ecological value and scientific research value, and other affected organisms (such as starfish, scallops and crustaceans), if they develop according to the trend of "high emission", it can be called the biggest ecological disaster in the history of human civilization. That's what oceanographers said from the beginning. Of course, it is too early to say that acidification will destroy coral reefs. At least, we still have a chance to save these beautiful and fragile things. The public's understanding of the ocean is the basis of rescue and protection.