【#第一文档网# 导语】以下是®第一文档网的小编为您整理的《鲸鱼为什么会灭绝英文作文》，欢迎阅读！
鲸鱼为什么会灭绝英文作文 Whales have been the targets of human hunting since ancient times because of their great economic value. However, in the past, due to the backward means of hunting, the hunting volume was small, which was not enough to affect the number of whales. In modern times, people used ships and artillery to hunt whales, which greatly increased their lethality, sharply reduced the number of whales, and many species were on the verge of extinction. The results of modern scientific research show that the ocean is a huge container for storing waste gas carbon dioxide, and the cold and hot ocean current system has a great impact on the earth's climate. In the deep sea, where little research has been carried out, there are many unknown animals and plants that are beneficial to human beings, including many potential sources of food and drugs, which are of great value. The increasing degree of marine pollution will destroy these valuable resources. Due to the destruction of the ozone layer, the population density of krill living in the waters around Antarctica has decreased sharply. The number of krill per 1000 cubic meters of seawater has decreased sharply from 177.8 before 1982 to 1984 to 41.2 from 1984 to 1985. Krill is a kind of crustacean in the ocean. It is an important bait for marine fish, whales and other marine mammals. It plays an extremely important role in the marine biological chain. As the largest protein resource preserved on the earth, krill has also attracted great attention. Because whales and other marine mammals are located at the end of the food chain, marine pollution, especially heavy metal pollution and other turbulence inducing substances, has seriously weakened their immune system, making them extremely vulnerable to viruses and bacteria. Pollution also prevents females from being pregnant or causing abortion, thus greatly reducing their reproductive rate. So it is gradually going extinct. 本文来源：https://www.dywdw.cn/079a65c407a1b0717fd5360cba1aa81144318fe0.html
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2023-03-18
