Wuzhizhou Island, located off the coast of China's tropical province, Hainan, attracts tourists from all over the country. One of the many reasons behind the island's popularity is scuba diving, which gives the adventurous a chance to see the beauty of coral up close.

However, the coral ecosystem has become severely affected due to environmental degradation and human activity, threatening the diversity of ocean life.

"I came to the company in the early 2000s. Back then, coral reefs under the sea were abundant, though I can't say they were all over the seabed. But because of the deterioration of the natural environment, such as typhoons and heavy rainfalls, the coral reefs were damaged severely," said Wang Fengguo, manager of the Marine Department on Wuzhizhou Island, who is also a coral planter.

Home to 25 percent of marine life, corals are essential for the biological balance of the ocean. The geological formation of coral reefs protects our land from wind and wave erosion. Also, it has the function of carbon sequestration and regulates the global climate to some extent.

"The coral reef ecosystem is unique due to its high biodiversity and productivity. It's called the rainforest of the sea and very much acts like one. About one-fourth of fish live in coral reefs. Now, they are being severely depleted," said Huang Hui, director of Hainan's Tropical Marine Biological Research Station.

"The survival rate for corals in south China is around one in 10,000. This is quite low. Unlike mammals, whose survival rates are higher, these lower-level organisms rely on large numbers. Only a few manage to survive out of millions of births," she explained.

Chinese scientists are now working to plant corals in the sea to restore the ecosystem. However, while coral planting is a restoration method, it's less efficient. Scientists emphasize the need for greater public awareness about coral reef protection and a balance between tourism and environmental preservation.

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