When it comes to sharks, many people think of their pointy fins（鱼鳍）and cruel nature. But there is more to sharks than their sharp teeth: The creature appeared on earth 410 million years ago, earlier than dinosaurs.

However, sharks are now at the edge of extinction. Numbers of oceanic sharks have declined by an alarming 71 percent over the past 50 years, according to a research published in Nature on Jan 27. “Such steep declines are shocking even to experts, especially when compared to land animal statistics,” said Sonja Fordham at Shark Advocates International. This alarming data may be an underestimate of reality due to unreported fish catches, Nathan Pacoureau, the study researcher, noted.

The study analyzed 31 species; 24 now risk extinction, and three shark species are now classified as critically endangered, including the oceanic whitetip shark and great hammerhead. The study found the decline hit the largest species first before impacting smaller ones over time, according to the International Union for Conservation of Nature （IUCN）. It also revealed shark finning and fishing worldwide have driven the decline. “The Indian Ocean is the worst. There is almost no fisheries management at all,” said Pacoureau.

“Overfishing of sharks endangers the health of entire ocean ecosystems as well as food safety for some countries,” said Nicholas Dulvy, professor from Canada. The researchers are calling on immediate action to make a brighter future for these “extraordinary, irreplaceable animals”, according to the BBC.

Although the situation looks disappointing, the future of sharks is still promising. Twenty-five species have returned to normal, due to long-term conservation campaigns in the past decades. A couple of shark species, including the great white, have started to recuperate through science-based fishing limits, Fordham said.

These examples “provide living proof that the world can set, and meet, ambitious biodiversity targets”, Jane Smart, global director of IUCN, said in a statement.

Photosynthesis (光合作用) is a unique skill of green plants—they turn water and carbon dioxide into oxygen and food via sunlight. A group of Chinese scientists, however, have “copied” the process on animals.

To understand the new breakthrough, it is important to know how photosynthesis works. Plants take in carbon dioxide and water from the air and soil. Within the plant cell, the water is oxidized. This transforms the water into oxygen and the carbon dioxide into glucose (葡萄糖). The plant then releases the oxygen back into the air and stores energy within the glucose molecules.

In the study, the researchers from Zhejiang University developed an independent and controllable photosynthetic system, according to the study published in Nature in early December, 2022. They separated thylakoids (内囊体), a part of the cell where light reactions take place in plants, from young spinach (菠菜) leaves. The scientists then wrapped the thylakoids with the cover of animal cells, which made the implanted thylakoids more acceptable to foreign bodies. The mice used in the study were suffering from arthritis (骨关节炎), meaning cells in their cartilage (软骨) had degenerated and could not be repaired by themselves. With the thylakoids implanted into the mice and exposed to light, the mice recovered. Their metabolism (新陈代谢) returned to normal. In arthritis, patients usually have energy loss since fewer energy-carrying molecules are generated. The implant, however, can correct the imbalance by storing more energy via photosynthesis. The researchers also claimed that their tests would have medical usage. It can be used as part of the solution for degenerative diseases because the natural photosynthesis system may repair cells. It may also delay the aging process in cells.

The study showed “an exciting achievement that opens up possibilities of metabolism engineering,” commented one of the paper’s reviewers Francisco Cejudo, from the University of Seville in Spain, reported Xinhua.