A Chinese scientific expedition team discovered that the illegally grounded Philippine military vessel near China's Ren'ai Reef in the South China Sea has rusted, with peeling paint and the leaching of heavy metals severely affecting the quality of surrounding waters, according to a report.

The "Report of the Illegally Grounded Military Vessel Destroying the Coral Reef Ecosystem at Ren'ai Reef", released on Monday by the Ministry of Natural Resources' South China Sea Ecological Center and the South China Sea Development Research Institute, said that personnel on the vessel are suspected of fishing, and fishing nets and garbage have led to extensive coral death.

The Philippine military vessel has been illegally grounded since 1999 near Ren'ai Reef, an uninhabited reef that is an integral part of China's Nansha Islands in the South China Sea. This not only seriously violates China's sovereignty but also causes continuous damage to the coral reef ecosystem, according to the report.

Xiong Xiaofei, chief scientist of the scientific expedition, said: "When I saw large areas of dead coral and fragmented coral reef pieces, I felt deeply saddened. Philippine fishing nets are entangled in the coral, and there is a large amount of garbage scattered around." The Philippine military vessel was run aground in the northern part of Ren'ai Reef, he added.

In April, a team of scientists conducted a comprehensive ecological environment survey at the reef.

"As a Chinese witnessing the destruction of our precious marine environment by the Philippines, my immediate reaction is that we must stop them. Such illegal grounding, illegal fishing and environmental pollution behavior are absolutely intolerable," said Xiong, who is also director of the South China Sea Ecological Center's National Field Scientific Observation Station for Nansha Coral Reefs.

Coral reefs, dubbed "underwater oases", are habitats for a large number of marine organisms and an essential component of marine ecosystems. Lyu Yihua, a researcher at the center, said that coral reefs grow slowly, and once damaged, recovery is difficult, affecting surrounding marine life.

"Many marine animals live on the coral reefs, with small fish taking the algae on its surface as food and attracting bigger fish, which add up to one of the most complicated ecosystems on Earth," Lyu said.